sn00p

Well i took the plunge today and walked out the shop a very pleased punter with a hobao hyper st rtr...... set the truggy up to my liking but have NO info on running the motor in. Hope 1 of you guys has some suggestions for me its a mach 28.

just going to pivk up glo starter from mates house now so a quick answer would be great

UG0TB4NN3D

My Feedback: (1)

This is taken directly from the [link=http://www.rcuniverse.com/forum/m_5517128/tm.htm]Nitro Guide and FAQs[/link].

I did this with mine.

revopqrs

wrap a sock around the head to retain heat, then start it up and run it as rich as possible for at least 5 tanks keeping the temps around 200ish... let it cool at bdc between tanks. im talkin rich! so that it can barely move itself.. dont turn high rpms until you get 10 tanks or so on it. at this point change plugs and turn the motor over by hand with the plug out, feel for the metal pinch, its kinda squeaky feeling. once you cant feel that squeak the motor is pretty much broken in.
the whole goal is to be nice to the motor until the pinch is gone, if you dont it stresses the cod rod and causes slop in the ends. thats bad...

keep the temps under 250ish when broken in. it can peak higher than that without probs, but in general shoot for 240ish. all motors like to run a lil different, not sure about the stock mill in a hyper, but itll be happy within those parameters.

good luck, and enjoy! the hyper is a great truck!

sn00p

so you guys are not running a couple of tanks in on the bench then??? just drive slowly

revopqrs

na... thats oldschool. its been updated, idling isnt needed. dont get me wrong tho, when you first start it up youll idle it untill its adjusted close enough to start putting around. but 2 tanks arent needed. just dont turn high rpms until the metal pinch is gone.... also i prefer to vary the rpms when putting around, i try not to just hold the trigger in 1 position... after 5 tanks or so you can start getting into a little power, just dont sustain high rpms.

madmax22

I did what revopqrs did but i put aluminum foil around the head. Have fun and enjoy!

rican25

first thing you want to do is toss that Mac-Star .28 in the garbage!!! you will probably never get it to hold a tune, it will always run very very hot, and it has zero bottom end!!! likes to rev and goes well when it does but very shortly thereafter it will be too hot to pull itself out of a wet paper bag. I have that same engine and just swapped it out for an Axial. best thing I ever did to the Hyper. I have to go get prestige mode so I will weigh in on this piece of junk motor more later. cya and good luck

sn00p

Well i ended up running 1/4 tank on the bench idling until it reached 200'ish and then took it out for 3 full tanks of driving slowly in figures of 8 changing the RPMS NO wot 1/2 throttle max for very short bursts on the 3rd tank.

Next day i ran another 2.5 tanks through it around a neat tarmac track slowly. On the final 1/2 tank i was gassing it wot but merely a secound or 2 on the straight so not enough to even reach high rpms or clear out. This has all been done on 20% nitro with 16% oil i.e running in fuel. When i bring the truck in i seem to be getting 250' on bog standard settings and like i say not really gassing it. Should i make the slow jet richer or just keep plugging away??? and finally at what point can i start using 25% race fuel and tune???

Sorry i cant find my instructionc anywhere. If anyone has a pdf or web link to the running in on these motors it would be great.

slayerphonics

First of all, this Nitro Guide and FAQs has been worked on by I (Sean Coots) and rccardude (Eric Brown) for the past 2 months. It is not complete and will be constantly updated and altered. If someone feels that our information is incorrect, please PM Eric or I about the problem and we can come to a resolution. The FAQ guide will be changed fairly frequently with new questions sent in by anyone to I (apollo) or Eric (rccardude). More guides should be available soon too. We hope that this guide is beneficial to many, and we urge you to post a link to this guide whenever necessary. Thank you.

Nitro Engine Break In Guide:

Okay, so you just got your brand new nitro R/C, you are psyched and ready to tear up the streets, but first you must perform a proper break in procedure for your engine unless you want to be buying a new one very soon.

So to start off, you will need to correctly adjust your linkages to work properly (see Linkage Setup below) and make sure your fuel tubing is routed properly (tank pickup to carburetor nipple, pipe pressure nipple to tank pressure fitting.

First, you will need to preheat the engine by taking a hairdryer or heat gun and heating the top of the engines cooling head for about a minute or a little more. Heating the engine up relieves cylinder pinch; therefore the engine will be much easier to crank over.

Side note: Pinch will make your engine hard to turn over. This is why your engine always seems to get stuck, the reason it happens is the cylinder is smaller at the top than it is at the bottom; therefore it’s harder to push the piston through at the top. The reason for pinch is compression, since nitro’s don’t have piston rings, we have to use pinch.

Now you just need to fill the fuel tank up with proper fuel and prime the engine.

Priming Techniques:
-Tank primer: Some fuel tanks are equipped with a built in tank primer; in this case, all you have to do is press down on the priming rod and watch the fuel go to the carburetor.
-Stinger priming: If your fuel tank is not equipped with a built in primer, then just put your finger over the pipe’s stinger (most people just call it the opening in the pipe) and then turn the engine over by means of pull start or whatever. This will push the fuel to the carburetor.
-Mouth priming: While it does sound discouraging, all you have to do is remove the fuel tubing from the exhaust pipe pressure fitting and blow into it (remember not to suck in or you will be drinking hazardous fuel), this will cause the fuel to be forced through the tubing and to the carburetor.

When priming an engine, there is no need to shove excess fuel into it in hopes of it starting easier (actually the opposite of what you think), all that is required is to bring the fuel to the carburetor, no more, once you see it just barely go in then stop and that is enough. If you get good enough at priming, then your engine can start easily on the 1st pull.


Once you have these steps completed, turn on the radio transmitter (TX) and the receiver (RX) and do a quick run through, testing brakes, linkages, carburetor opening, and steering. Now place your fully charged glow igniter on the glow plug and crank the engine by pull start, roto-start, or whatever is used.

Once the engine starts, leave the glow plug igniter in place and begin to slowly drive the car around while varying the engines rpm. Now remove the igniter, if the engine immediately dies then it is running too rich. (Now is the perfect time to read the tuning article below) It is critical at this point to get your engine to a minimal operating temperature, I recommend this to be anywhere from 200*-240* for break in. At this point, it is okay to do 1 second WOT (wide open throttle, aka 100% throttle) bursts. After driving the vehicle around for 2-3 minutes, shut the engine down (read “Engine Stopping Methods� below�) Now you will need to set the engine at BDC (Bottom Dead Center, when the piston is all the way down in the cylinder), to do this, turn the flywheel (or pull starter) until you feel the least amount of resistance and then stop there. This ensures that the piston will not be stuck in the top of the cylinder while it cools. Note: during engine break in, small metal fragments can melt themselves to the glow plug therefore fouling it, so it is wise to have at least 1 spare glow plug for break in.

Let the engine sit and cool down to room temperature, you can lessen the cooling time by blowing compressed air over the head or a hairdryer set to cool. DO NOT SHOCK IT COOL WITH ANY LIQUID AT ALL. Now, repeat the process, adding about 1 minute of run time to each cycle completed. Do this until the engine has run about 15-20 minutes total. Now you are ready to finish properly tuning the engine and then rip it up wherever you want.





Nitro Engine Tuning Basics:

NOTE: ALL TUNING MUST BE DONE AT OPERATING TEMPERATURE

Rich: An excessive amount of fuel entering the engine, more fuel means more oil, which
typically lowers the operating temperature. Rich=counterclockwise

Lean: An insufficient amount of fuel entering the engine, less fuel means less oil, this
causes more friction, higher temperatures, and engine damage. Lean=clockwise

High Speed Needle:

The High Speed Needle (HSN) valve is the tall valve that sticks out from the top of your carburetor. Its job is to control the main flow of fuel to the carburetor. If you lean out the HSN, the LSN (Low Speed Needle) will be automatically leaned too (think of it this way, the HSN is the garden hose faucet which controls all of what goes in, the LSN is the nozzle which controls the exact amount that comes out). The HSN mainly effects the top speed of the car. If your HSN is set too rich, the engine will typically not reach its full RPM potential. If the HSN is too lean, you can experience hesitation, overheating and flameouts (engine instantly shutting off at random or at higher RPM’s). WARNING!!!! The HSN IS NOT to be used as a thermostat. Yes tuning effects running temperature, but only half of it. In the cold, you will typically have to set your needles richer because cold air carries more oxygen, therefore with the previous settings you will be running too lean.

Low Speed Needle:

The Low Speed Needle (LSN) is used for fine adjusting the rate of fuel flowing into the engine from the HSN. If your LSN is too lean then you will have erratic idling, it might want to drive off without you, and it can suddenly shut off (flame out). A characteristic of an overly lean LSN will be a random surging and sound “angry� so to speak. It also will have sporadic RPM increases. Too rich of a LSN will make the idle sound deep and rough, at idle the RPM will slowly decrease and then shut off due to the excess fuel building up, it will also cause consistent sluggish acceleration all the way up the RPM range, and this is what makes it different from a lean bog.

The best way to test your LSN is to get your engine running at normal operating temperature, drive it around, and then let it sit and idle for 30 seconds. Once 30 seconds is over, apply a lot of throttle, if it is rich you will notice slow, gurgly acceleration, if this happens, lean the LSN out by 1/8th of a turn and then test it again, if it is lean, chances are it will flame out or have random surges. In this case you would richen the LSN up by 1/8th of a turn at a time. Your LSN will be set near optimum position when you have little to no hesitation after 30 seconds of idling.

Keep in mind that an engines tune changes day by day, every time you get our your engine and run it, you should tweak the needles a little bit (typically). One day your engine can run fine, the next day it can be running extremely lean.
NOTE: Tune the HSN first because it controls the full amount of fuel entering the carburetor, and then tune the LSN because it is a fine adjustment screw.

As a side note, if you do a lot of wide open running at WOT (Wide Open Throttle, a.k.a. full throttle) your engine will need extra lubrication and it could need to be set 1/4th turn rich to ensure proper lubrication to your engine at high RPM’s.

Here is a good little graphic that for the record I did not make, I simply found it very helpful.



Vapor Lock:

If you have ever shut off your engine or had it flame out while you are using it, and you find that it’s nearly impossible to restart, you are most likely experiencing something called “vapor lock�. Vapor lock is caused by the heat from the engine transferring to the carburetor. In turn it makes the carburetor so hot that whatever fuel that enters it boils off instantly into vapor. Hence the name “vapor lock�. A common giveaway to vapor lock is when you prime your engine; you’ll see that the fuel in your fuel line is pushed away from the carburetor. The only way to run the engine again is to cool the carburetor off enough so that it does not boil the fuel. The most common way is to let your engine sit for five minutes and then try again. Another way is to use cans of compressed CO2 or compressed air cans used for airbrushing and spray the carburetor. Or you can pull off your air filter and dump a little bit of fuel over the carburetor which will rapidly cool it. Just be careful not to get fuel on your brakes or electronics.

Air Leaks:

An air leak is when your engine has unregulated air being sucked in. By unregulated I mean it doesn’t come in through the carburetor. This causes a problem because it can suck in air causing your engine which could be tuned perfectly, to run extremely lean and cause engine damage. It could also cause your extremely rich engine to run lean and well over 300 degrees. If you have an air leak you can look forward to inconsistent tuning and idling, it will seem impossible to find a good tune. Keep in mind that even brand new engines can have air leaks. Here is a good link on How To Seal Your Engine. For the record I did not write that, I am simply posting a link to a helpful guide so moderators, please don’t delete this. Oh and a good place to get RTV silicone sealant and your local auto parts store. You can also use the stuff to seal side exhaust headers and make a gasket so you will never rip another paper gasket again.





Glow Plug Guide:

Without a glow plug, your engine won’t run, simple enough. Now without the right glow plug, your engine just won’t run properly, simple concept. But you are saying to yourself, “Well, how do I know what the proper glow plug is for me?� Well this is a fairly simple question to answer. Glow plugs work by adding compression, heat, and a catalytic reaction between the methanol in the fuel and the platinum in the coil.

Companies rate and sell their glow plugs by their “heat range�. The different general heat ranges are cold, medium, and hot. The heat range of the glow plug is what determines the exact time that the fuel/air mixture being compressed in the cylinder ignites and pushes the piston down. While this sounds like a simple thing, it is absolutely vital to your engines performance. So let’s go on to the function of each type of glow plug and their proper applications.

Hot Glow Plugs:

When you run an engine with a hot glow plug, the compressed fuel/air mixture in the cylinder ignites earlier (more advanced ignition) than a medium or a cold plug would. Hot glow plugs are normally used with low-nitro content (5-20%) fuels to advance the timing and igniter the fuel earlier. Lower nitro fuels burn slower, therefore the mixture must be ignited sooner for the engine to run properly. To hot of a glow plug for your certain nitro percentage can cause pre-detonation and permanent engine damage. An example of a hot glow plug would be the O.S. A3.

Medium Glow Plugs:

Medium glow plugs work the same way that hot glow plugs do, but the do not ignite the fuel as early (more retarded or delayed ignition). Medium glow plugs are often used in medium-nitro fuels (20-30%). An example of a medium glow plug would be the HPI R3.

Cold Glow Plugs:

Cold glow plugs are just like the other glow plugs, but instead, they are meant to be used in engines running high-nitro fuels (30%+). An example of a cold glow plug would be the HPI R5. Cold glow plugs typically have a thicker element in them than a medium or hot glow plug.

Turbo vs. Non-Turbo glow plugs:

Glow plugs come in 2 different styles, Turbo and Non-Turbo. Now before you start thinking “Oh turbo must mean fast, I need that� lets discuss the difference in them.

Turbo Glow Plugs:

Turbo glow plugs differ from standard, non-turbo plugs because they use a tapered edge to make a tight seal between the head button and the cylinder. This lets them to run without a copper washer for a gasket, and also allows them to have a smoother head button which adds a tiny bit of power. An example of a turbo glow plug would be the O.S. P3. Note that you can clearly see the tapered edge.

Non-turbo glow plugs do not have a tapered edge to form a seal between the cylinder and the head button, Instead the use a copper washer. Non-turbo glow plugs (commonly called standard glow plugs) use a different head button than a turbo plug would. The head button is not as smooth; this in turn takes away a tiny bit of power. A good example of a standard plug would be the O.S. 8

How To Read Glow Plugs:

If you know much about 1:1 scale car racing, you will know that teams examine the spark plugs that have been used in the engine while racing, then they use a method called “spark plug reading� to determine how the engine is tuned. Well for scale model cars running 2-stroke nitro engines, there is a method of doing this. It is called “glow plug reading�. Here is a general how-to guide on reading glow plugs. (Note: this is meant for new glow plugs, it cannot be accurately done on glow plugs that have been run for a while)

1. Wire and surrounding bottom of plug wet, with like new shiny wire = rich side of optimum power
2. Wire and surrounding bottom of plug starting to dry and wire starting to gray = very close to optimum power
3. Wire and surrounding bottom of plug dry, wire totally gray but not distorted optimum power
4. Wire and surrounding bottom of pug dry, wire distorted = slightly lean "DANGER!"
5. Wire and surrounding bottom of plug dry, wire broken and distorted or burnt up = extremely lean possible engine damage!

Note: For the record I did not write this “How To Read Glow Plugs� guide and I am using it merely as a helpful guide.





Complete Nitro Fuel Guide:

Most 2-stroke glow fuel engines (with the exception of a few) run on what is commonly called “glow fuel� or “nitro fuel�. Basic glow fuel is comprised of 3 main ingredients: nitromethane, methanol, and oil. Sometimes fuel manufacturers will add friction modifiers (a.k.a. additives) to help improve the overall performance of the fuel. But I will not be going into details on additives.

Fuel Can Go Bad:

You might be asking yourself right now, “What makes my fuel go bad?� Well there are a few things that can cause this. Most of the glow fuel that you use is comprised mainly of methanol (alcohol). One of the characteristics of methanol is that it is �hygroscopic� , this means that it will freely pull moisture from the air and absorb it since water is soluble in methanol.

Contamination with water is the main reason that fuel goes bad. Contaminated fuel often makes an engine hard to start, tune, or keep running consistently. Another enemy of glow fuel is the sun’s UV rays. These UV rays in sunlight can slowly break down the nitromethane in the fuel, especially if it is stored in sunlight for extended periods of time.


Proper Fuel Storage:

Yes, there is a proper way to do everything, even storing your own glow fuel. Ever noticed when you are almost finished off with a jug of fuel, that there is a lot of empty space in the jug? This is the perfect opportunity for condensation to form in your fuel jug and contaminate it. Below is a picture of how to store your fuel. All fuel should be kept in a cool, dark, dry area if possible.

Try to squeeze as much air out of the jug as possible, but be careful, squeezing the jug too hard can puncture an edge (like I have done) and therefore ruin the jug.

Remember these little things?

Whenever you open up a fresh gallon of fuel, make sure to put this back in the top to provide a moisture barrier.

Oil Content:

All internal combustion engines require oil to operate, if there were no oil in the fuel, our engines would just seize up and never work again. Although this is true for 2-strokes and 4-strokes alike, different methods are employed to accomplish this.

Our 2-stroke glow fuel already has it oil mixed into it. This is what makes it simple; one of the not so simple parts is the actual oil content in the fuel. Though there is not much to say about this, anywhere from 8-18% are acceptable for glow engines used in land vehicles. Fuels ranging from 8-10% in oil content are considered low-oil fuels, and are primarily intended for the experienced tuners who are trying to get the most power out of their engines while racing. For normal bashing, anywhere from 11-16% oil content is acceptable; any more than 16% oil content does little to provide extra protection.

Oil Types:

In our glow fuels, there are 2 main types of lubricants (a.k.a. oils) primarily used in them; these are castor oils and synthetic oils. The general rule of thumb is to buy a castor/synthetic blend fuel, so you get the best of both worlds.

Castor Oils:

Castor oil is derived from the bean of a castor plant (originally used as a natural laxative) and is the best lubricant you can have in a fuel. It provides the best over-lean protection that you can get, and it only keeps breaking down into a better and better lubricant as it is heated (combusted) in an engine. Finally at around 800*F if memory serves me correct, it burns, which is much higher than synthetic oils. After running fuels with high castor oil content you might notice a brown “varnish� on the engine’s internals, this “varnish� is an anti-scuff layer left behind from the castor oil, most people believe this is bad and remove it, however, this helps protect the engine (to a certain extent) in the case of an over-lean run.

Castor oil is mainly used as an EP (Extreme Pressure) additive in nitro engines because they create an excess amount of friction due to the RPM’s that they crank out. If you have ever tried to purchase pure castor oil, especially AA grade, then you have learned that it isn’t a cheap product, this is why companies use less castor oil (if any at all) in their fuel blends. It is highly encouraged that when choosing a fuel, that there be at least some castor oil content in it. I myself have run on fuel that used nothing but castor oil in it, and I can say from experience that it drastically lowers the temperatures and allows you to run leaner (which helps efficiency) without any detrimental effects. This is how some fuel brands like White Lightning are able to run such low oil content in their fuels.

Synthetic oils are typically derived from refined petroleum extracts, and are often chemically altered to be a custom friction modifier. Synthetic oils are cheaper to manufacture, therefore most fuel companies make this a majority of their oil content in a gallon of fuel. Synthetic oils are just as “slippery� as castor oil, but the main difference is that castor oil does not typically burn in the combustion process, while the synthetic oil is often completely consumed. Synthetic oils provide very little over-lean protection when being used.

Some fuel blends from Blue Thunder run full-synthetic oils in them. I have had personal experience with these and do not like them because they are not very forgiving if you run lean. However, many have had success with them; with the right needle setting you will get great protection from them as well. Just as an example, here is a picture of an O.S. 12TZ that was ran a little too lean on Blue Thunder.


Nitromethane Content:

Although our fuels are mainly methanol, we love to call them “nitro� fuels because it simply sounds better. But what is this “nitro� referring to? Well if you read this whole article, you will know that nitro is short for “nitromethane�. But why do our fuels use nitromethane?

Well for starters, nitromethane allows our engines to gain more power because it is basically liquid oxygen, so to speak. It is an oxidizer, which means that during a chemical reaction, it releases oxygen. Oxygen is what reacts with the fuel, therefore more oxygen = more fuel able to be burned. The more fuel that is able to be burned, the more power that can be made. So in a nutshell, more nitro = more power, less nitro = less power, simple enough.

The second reason that nitromethane is used in our glow fuels is that is makes tuning A LOT easier (and starting for that matter). If you have ever tried to tune an engine on zero-nitro fuel, you will realize that makes less power for starters, and that the tuning needles are a lot more sensitive to input.

Higher Nitro Content:

Raising the nitro content is a simple way to add more power, but there are also other things you must do. When you raise the nitro content in your fuel, you are capable of burning more fuel. This creates a larger “bang� in the cylinder, therefore raising the pressure. If your pressure gets too high, you will encounter pre-detonation which can cause serious damage to your engine.

When changing to high-nitro fuels, it is usually advised to add a head shim which lowers compression, and to run a slightly cooler glow plug which also helps prevent pre-detonation.

Lower Nitro Content:

Lowering the nitro content in your fuel can reduce the power output of your engine. When you lower the nitro content in your fuel, usually you should just run a hotter plug. Whenever this is not sufficient, you must also raise the compression in the engine by removing a head shim if possible.


The FAQ section should be up shortly. Both Eric and I ask that you please only link to this post and not just copy and paste our work that has taken us months to compile. Thank you





This is from a post in the engine part of the forum not my writing but good info

rican25

greatb post Slayer, snoop you still have this engine huh? well good luck with it but I am telling you and I have read here as well that it is probably the worst RTR engine ever!! I dont want to just slam your engine but I wouldnt do it if I havent been through of all of the pains and headaches myself. I had 2 or 3 very experienced nitro guys try and tune the engine and none of them could get it to run cool for very long and when we did it ran like crap because it was so rich. I hope you have better luck and maybe its just mine who knows? but for now the .32 in the Hyper just screams and I am enjoying that to the fullest well until my JP pipe gets here! Good luck let us know how you made out.

sn00p

hmmmn. I gotta say im fairly happy with the engine all though its isnt screaming and has a slight bog off the line. Temps yep they are up there in the 260+. Not too bothered as i'll just replace the engine as and when.

Now ive been reading up on tuning and there seems to be a wealth of both neg and pos feedback... More to the point i see many variations in settings too.

Now my truggy came with pretty much the same stock as stated on CML and NOT what is stated in the instructions of which i have now found.

CML stock

HSN 4.5
LSN 6.5

Instructions say and GET this......

2.5 for the LSN ?????? as stock (geesh)

If you read on here http://www.cmldistribution.co.uk/pro...view_May07.pdf they then state after tuning HSN 2.75 and LSN 4

Why the hell does the instructions mention 2.5 stock for the LSN. Please correct me if im wrong but isnt 2.5 seriously lean on the LSN??? im pressuming leaning the LSN is turning it clockwise or screwing it in?

At the moment i have mine set at HSN 2.25 and the LSN at 6.8. Have good top end still with plenty of smoke (20% nitro 16% oil) however i do have bog off the bottom unless i gradually feather the throttle on... i.e 0-100% instantly i get a stammer of bog then it picks up??? i reckon to rich on the LSN but i have no idea???

I tried the CML HSN 2.75 and dont get clear out and lack speed generally. If i then go to leaner or richer on the LSN i get MORE bog no matter what way i try it??? If i try the exact settings CML state (LSN 4)the car just concks out.

adam-69

hmm, close, but you have clearly never had any experience with a cen nx-26 haha.

sn00p

Geesh

I decided to run 25% race fuel over the weekend and see what this truck will do... Now im even more confused with the needle settings. Truggy wont even start on anything less than 6 rich (out/counter clockwise)on the LSN..... im now running something like 3 out on the HSN and 7.25 on the LSN[sm=71_71.gif].... NO bog off the bottom although still a little slow on the pickup. Mid to Top end is VERY powerful and consistently smooth. I can now whack the throttle from 0-100% and get a very reasonable pull away but it isnt lightning off the start line until it reaches the mid and then it takes off The weather was REALLY cold and fresh Saturday and had to call it a day so a little more fidling required... Im just concerned at just how far im having to run the LSN??? its almost out of the socket. I think im going to rip the needles out and check i have NO blockage as this MAY be reason.... At 7.25 i only have a thin smoke trail at low rev range but good smoke there onwards (especially where the engine is really racing and nice and revvy) so i think i need to be a bit richer on the LSN than i am already. It just doesnt make sense.

Thinking outside the box as someone put it i did kinda think that maybe i was to lean on the HSN and making up for it by richening the LSN so i tried 4 out on the HSN and and leaned the LSN right off but found the engine wouldnt run at all at 4 or under..... bogged like a ***** until i got the LSN up to 6+.... started backing the HSN down to around the 3 mark to get good top end then finished with the LSN around 7.25

Anyone has any thoughts on this??? im using a mcoy MC59 plug with Byron 25% nitro (11% oil) as per recommended

sn00p

Well no replies so i will add what i know for anyone else who may be interested or in a similar predicament. Back out again yesterday afternoon, very crisp cold weather again so i dont doubt ive had to richen it up a little more than i would when the weather gets better.

With the settings left from the weekend the truggy fired in to life with 1 tug after getting fuel to the carb Not the usual ritual of getting my knuckles busted up and blisters on my inner fingers.... So i set about getting the truggy up to temperature and then tried tried the "think outside of the box" theory and richened the HSN up and then tried to lean off the LSN. NOT a good idea..... Run like a sack

Fiddled with the settings for an hr or so doing 3 laps of the track before tempting to read temp and or change the tunning. It deffinately runs the best at 7.25 LSN and 2.25 - 2.5 on the HSN. Anymore on the HSN and it doesnt clear out at top end. LSN didnt really make much difference 1/4 turn either way either so im hopefull its now set about right. I left the truggy idling for 30 secs and whack the throttle from 0-100% and get NO bog or hesitation just constant smooth pulling. Should mean the LSN is just about spot on. It really seems to be the HSN thats fussy. Anymore or less than 2.25-2.5 and it really doesnt like it. ANyways with these settings when i got home i check the plug to see what state the engine had been running and it all looked good. A tad richer than leaner as the base of the plug had brownish tarnish with a wet area. Slightly blackened and the wire was just ever so slightly greyed so running at a good temp. BTW that .25 (2.25-2.5) difference on the HSN makes a 20-40' difference on the temps FYI.

Overall im pretty happy with the performance but this is NO race engine. It'll just about beat my mates WELL tuned savage 4.6 off the line,well maybe comfortably but not like a ferrari and and mini if you know what i mean. But the real gift is the cornering I just back off the gas and let the truggy roll the corners at such a high speed its crazy. Leaves the savage standing. Im mean really, within 3 laps its catching back up to the savvy yet they have similar accelration and top end...

DId you notice i mentioned backing off the gas all the way round the corners thats because when you put the power on the back end is NOT loose enough for my style driving as it ends up pushing the front end out round the corners and results in far less tighter turns. Its prolly due to diff oil so i'll post back with results soon. I like to back end steer for hard sharp turns.

qaiz

Good to hear its all sorted out.

How you likeing the Hyper so far.?

I really need to get mine in tune.!

Chopped02

I feel your pain on the NX 26. I had one in my Matrix and never got it to run right. CEN tried helping by sending me a new one and that one never ran more than about a quart through it. I gave up and bought an OS. Best thing I ever did. Sorry, a little off topic. [&:]

sn00p

Quaiz its all MacDonalds mate. REALLY im loving it. In the past ive had a few pimped out rides inc hyper 7 pro, revo and savage.I was 1 of the first to own the revo here in the uk back in the day, after getting lucky and getting 1 of the first shipped out of the USA. I reckon i spent close to £1200 on my savage with radio gear and just about every hop up available to man and beast, it was a real tool, all setup for hardcore bashing. But i reckon im loving the stock RTR Hyper St a little more. I took it down to a local BMX dirtjump area this weekend just gone to get it going on a bit of loose dirt and try the jumping out on it. I gotta say outta the box i was not very pleased when i dropped the truggy from waiste height to see what it was like and i got chassis slap and a few scratches on my brand new fresh out the box chassis plate My mates face who still owns a savage just said it all.... I thought i was in real trouble so i jacked the thing up with the spring pre-loaders.... little did i realise this just made it totally unstable for regular driving so i removed them before going to the dirtjumps and left them at home forgetting them. Now I was a little worried(no preloaders with us) but none the less i started hitting the jumps like 1/4 throttle and managing to clear them without a problem. This truggy stays planted and lands soooo sweet. Anyways after a short period of time i decided to see exactly what it could do and to my surprise as well as my friend with the blinged savage i was hitting the jumps at full throttle with a pretty much full run up (so 90% top end speed) The truggy Flies through the air like a real aircraft, with precision landings with just a smidgen of throttle/brake control. The look on my mates face was just amazing.... soaked the jumps up nicley and balanced. I was landing on the downside of a hip jump but getting serious length and height. Played the rest of the afternoon on the jumps and have only 1 small problem so far. I managed to snap the head off of 1 of the engine mount bolts (underside ones). Going to upgrade to a stainless screw set so no big deal its just a stupid idea having them 4 bolts in the recess yet they put dome bolts in that stick out proud of the chassis??? This was most prolly when i got 1 of the jumps slightly wrong and managed to case the top of a hip jump thats prolly 30ft long and getting 10' air so quite a slap on the way down lol... My friend commented on not daring to jump so far with his savage which kinda made me chuckle. Roll on the weekend.

sn00p

I posted a reply yesterday to 2 threads and now they have gone missing...

Anyways, A lot more tuning was carried out last week in the evenings and tested again at the weekend when the weather warmed up considerably and it held its tune no problem and runs like a cheetah. This is coming up on par to be a good mediocre engine. Some VERY strange settings of which im guessing why no one else has managed to get their engines singing without heat problems...

MCCoy 9 plug
Byrons 25% race fuel
HSN 1.8
LSN 7.25

1/3 turn leaner on the mid needle. (BE VERY carefull playing with this baby and remeber whatever adjustments you make as there is NO set from factory other than roughly flush with body)

The engine now has a breath of new life and has legs like ive not seen for a while... still runs in at around the 240' mark. I now have a complete set of bald tires from just 2 tanks of fuel running it on the tarmac tuning lol.... Really mad me angry at first but after thinking i was happy to bald the tires just to have the truggy singing and reaaly going for it. Leaves a savage 4.6 standing like its out of fuel lol......

It got to the point that i didnt care for the engine anymore unles i could get it to perform as well as it finally does so i went ballz out and played with the radical settings until i was happy. Even now the HSN could be leaned off 1/4 turn with more top end and only a 20' hike in the temperaure which still gives a reasonable 260'. This was all acheived on tarmac mind with long straights... I did managed to take it to the dirtjumps sunday but forgot my temp gun.... Truggy behaved well with a noticeable power increase allowing for quick blips between the six pack for easy clearance.. The up hill section it just seemed to breeze it. no histation or stalls just pure screaming fun.... this is the older type engine with the black cooilng head NOT the new turbo head type.....

All i can say if you have 1 of these engines (stock rtr) then perservere and at least try some of the more out there settings before jum=ning it to the garbage can. I will at this point openly admit that bottom end its a little slow off the mark but even the slowest of a rolling start and it really does rip.... Maybe i got lucky or maybe it will go bang very soon. Fingers X'd.

Big Daddy05

Hey everyone,

I am really new to tuning the motor, so I am hoping you could help me out. I just got the Hyper ST RTR with the .28 Mac.

When you are sugguesting to adjust the HSN, and LSN to 4.5, 6.5 etc..., I am assuming that these are how many turns you are turning the screws, is that correct?

If so, do you start counting when they are all the way closed? When do you start tuning like this? I have about 7 tanks of gas through this engine.

One other question, I used to run electric, and I knew how to adjust the slipper clutch. Is there a slipper clutch on this truck, and how do you adjust it?

Thanks in advance for you help.

sn00p

NO slipper clutch check you manual it has a 3 shoe configuration that works on springs and cetrafugal force. NO adjustments other than spring replacement with softer/harder types or buy an adjustable clutch with weights in the shoes.

As for tuning them settings are from closed.... BE CAREFULL when tightening them down just nip it down or you will bend the end of the needle if you force it shut/closed too much.

Just an update i ran the truck again this weekend with good results although i did need to fiddle with the HSN maybe 1/8 - 1/4 turn richer to start off with and then lean it back a while later. This was probably due to me over doing the after run oil last time i took it out as by the time i had run the truck for 20 mins i found myself back with the same settings as i did last week.

so FYI im still at:-

MCCoy 9 plug
Byrons 25% race fuel
HSN 1.8
LSN 7.25


Only i have now swapped to an OS8 plug (all the shop had). I havent seen or heard anyone else using these settings so i will add try AT YOUR OWN RISK. and before you lean the HSN make SURE you have richened up the LSN to 7.25. That way at least your rich on the bottom. Try running for short periods of time and regulary checking for max temp (if you dont have a temp gun use a blob of spit on the head. if the spit sizzles and disappears VERY quickly your to lean it should sizzle and and stay for around 3 secounds or so and longer and your to rich) Slowly build the full threottle bursts until you get a good 10 secounds if your temp is still good then fine.... tune it to around the 260 with a max peak of 290' if you want ballz out if your happy to run and bash id go for 250-260' as this will last a whole lot longer.

Finally after EVERY time your finished or waiting for the engine to cool make sure the piston is at the bottom. Just pull the pull chord and when its is at its slackest the piston is at the bottom. Saves the piston seizing whilst cooling. Oh and dont forget after run oil. takes 1 min to put in but saves the engine. 5-8 drips in the glo plug hole. and the same in the carb mouth where the filter joins with the slide open i nearly always forget the carb mouth but this will put oil in the crankcase rather than the cylinder.

Empty your tank of fuel everytime your finshed with it too and blow the line from the exhaust with the lid open so the excess fuel goes back into the tank. Nitro attracts water/moister so i either empty tank back in bottle or keep the truck in a dry warm place NEVER oiut in the garage or alike unless ive really oiled it well.

Big Daddy05

Thanks for the info Snoop.

So I tried to adjust the HSN, and the LSN, and what I thought was the idle. After looking on the OFNA website, I think I adjusted the mid-range.

The one I am referring to is on the opposite side from the LSN/HSN and has a blue plactic piece that is connected to the throttle servo, so I thought is was the idle.

That was stupid of me, because now the truck stalls every time I give it a little gas.

Does anyone know where this needs to be so it will be the stock setting again?

sn00p

Flush with the body of the of the srew hole.... thats within 1/2 turn of being correct as there is 1/2 turn play with the screw head still looking like its flush.

Im confident you can get it running sweet-ish just make sure you have the engine fully warmed up after setting the screw flush and then fine tune from there.

Big Daddy05

Thanks again snoop. I am excited at the potential after reading your posts. My plan is to make all the needles flush again and theny try starting.

sn00p

FFS my posts have been deleted AGAIN... Yes i know there is an issue and they have to keep rolling back but its begining to annoy me lol.....

Right stock should have been (ignore the booklet or instructions they where way off the mark for anyone i spoke too):-

As new or stock from box:-
HSN6.5
MSN flush
LSN 4.5

get car wamred up. lean the HSN to your happy its got as much top end as possible then screw back out 1/4 turn just to be safe. then try richening the LSN like i did and see if you get good results. please be VERY careful going less than what im running on the LSN if your about the same as i am on the HSN

so to clarify

im now running

HSN anywhere between 2.25 and 1 3/4 out (be carefull going below 2.25 make sure you have already richened the LSN) depending on weather
LSN 7.25
MSN 1/4- 1/8 leaner than stock of which youve already moved so make this the last ditch attempt to play with.

I really cant say more than im STOKED with the engines performance it really does rip you can clearly hear it screaming... in my opinion it is a little slow off the mark but as said before from little more than just a rolling start it will pick up very quickly. Ive thought about changing the the clutch bell to get better bottom end but to be honest im too happy with the mid- top to worry. My suspicions are the pipe is holding the bottom back if anything.

Post back and let us know how you get on. Oh and good luck

Big Daddy05

I just want to start out by saying that I am really frustrated right now.

When I bought the HyperST I thought it would be a good idea to have the roto start that is made for this truck installed. I am begining to doubt my decision. Here is what is going on;

I have tried to start the truck every day after work since Monday, but I have been unsuccessful. So today I took it to my LHS were they have been very helpful. Without any moving of the needles (all flush) or any heating up of the engine they were able to start the truck. At first they flooded it but got it to start.

The guy tuned it up for me, leaving it a little on the rich side due to the outside temp still in the upper 40's low 50's. I got to run the truck and it ran great . I had to go back to work so I shut it off before the tank was empty, figuring I would run it after work.

I take it home after work and try to start it. I still can't get it to start, sometimes I flood it, sometimes not. I am wondering if the drill I am using does not have enough RPMS. It does not sound like there is much compression, but it is not flooded.

I think the roto start is slipping and therefore not creating enough compression. So my thought is to put the pull start back on but I don't know if that would solve the problem, but I would at least know the compression issue is due to the roto start.

I don't want to go back to the LHS because every time I bring it back they are able to start it right up.

Any thoughts?