YS 120 NZ Supercharged dos and donts
 

Just bought on eof these and was going to mount it inverted in a scale spit, any dos and donts or tips i should know about peeps.

Thanks

tim


ps Do i need to go and buy 30 percent fully synthtic oil or will 10 percent dyna glow do?

RE: YS 120 NZ Supercharged dos and donts
 

Don't know which engine you have.

YS never made a NZ.

They made a 120NC back in about 1994-1998

They also produced a 120FZ from about 2000 to about 2003. There is an easy way to tell the difference between the 120NC and the 120FZ.

The 120FZ has a air bleed screw on the needle valve side of the throttle barrel on the carburator. Also the 120FZ has a big nub or knuckle on the rear of the carb body that is used for the YS engine mount. The older 120NC did not have this mounting point at the rear of the engine and it did not have the air bleed idle adjusting screw.


Either way the minimum fuel recommended is 15% but higher nitro content makes the engine easier to operate and set. The mixture settings become more broad. My personal recommendation is to use at leasta 20% nitro and 20% all synthetic oil fuel. If you are good at getting the setting on the engine then 15% will work fine. However a less experienced modeler with setting YS engines will tend to struggle with the 15% nitro fuel.

The biggest thing on YS enigne is not to use any oil that contans petoleum products.

A good source for info is here....and its even on your side of the Atlantic Ocean.

http://www.probuild-uk.co.uk/factsheets/ys_engines.php


Troy Newman
Team YS

RE: YS 120 NZ Supercharged dos and donts
 

Hi

Yep sorry its the NC Version[:@]

I think i may of made an error then , I was hoping for an engine that wasnt so dificult to tune although I am an experienced modeller.

Are YS reliable and can you only use synthetic fuel with them?

Thanks again

RE: YS 120 NZ Supercharged dos and donts
 

YS engines are not difficult to operate they just are slightly different than most normal glow engines.

YS engines are high performance engines and with their high performance levels come slightly different tuning techniques. These are not difficult to learn, but some inexperienced modelers struggle at times. Following the notes on the website posted above will help you get the most out of your engine.

Some will argue the point but I personally believe that YS engines are the most power for the size engine available. They also idle extremely smooth and transition through mid throttle settings better than any other model engines. Setup properly they are a joy to operate and fly. They do have their quirks but these are not difficult to learn.

By the way the 120NC is the easiest of all the YS engines to operate. It is not "super charged" and hopped up to produce excess power. Its made to just run reliably. The 120NC and 140FZ-140FZ Sport are probably the easiest to operate of all the YS engines.

Yes you should use only synthetic oil in the fuels. There are some that choose a small amount of castor oil but I don't personally recomend it.

Troy Newman
Team YS

RE: YS 120 NZ Supercharged dos and donts
 

Thanks troy for the help

Its actually going on a 1.8m wingspan spitfire so it will be fairly overpowered i reckon lol

What propeller would you recomend to put on it bearing in mind its virtually broken in now.

Thanks again

Tim

RE: YS 120 NZ Supercharged dos and donts
 

Prop choice will dpend on your fuel choice.

The more nitro the higher the prop load.

You should run the engine about 8400-8800 maybe as high as 9000 but I would not go much higher.

So choose a prop that will work in this rpm range. Perhaps 15-10 or 16-8 depending on the your fuel again.

In a war bird you will likely want good speed and is really good speed. Perhaps a 14-12 would be a good option as well.


Troy Newman
Team YS

RE: YS 120 NZ Supercharged dos and donts
 

Ive bought some powermaster 30 percent Nitro this afternoon so I suppose a 17X6 should do it?

Great replies Troy very professional

RE: YS 120 NZ Supercharged dos and donts
 

Try the 17" prop but I suspect you might get better performance from something smaller diameter and more pitch. Especially in a war bird model.

First off the 17" props tend to get heavier and the laod on the engine goes up. Not that a 17-6 should be too much load, but also the really flat pitch props will tend to be too stop and go for Warbird flying. They are better at 3D type of flying. Personally I don't like them at all. The engine revs up but doesn't do much, and the model never gets up on its step and flying.

The 30% Powermaster will be excellent, good luck and let us know how it goes.

Troy

RE: YS 120 NZ Supercharged dos and donts
 

Troy,
Correct me if I am wrong, but I thought all YS four strokes are "Super Charged", it just does not have the extra airbox or crankshaft ring.

RE: YS 120 NZ Supercharged dos and donts
 

Yes and No

Technically yes the 120NC has the disc valve assembly preparing the next charge using pressure from the downstroke of the piston.

However the 120NC doesn't have the chamber to store the charge and make effective use of it.

many of the larger YS engines in fact the 120sc on the airbox or air chamber to store the charge is the valve cover area. The 91's and 110s still have the air chamber box.


So the prepared charge has a place to go and wait to be forced into the head when the valve opens. On the Non Chambered engines there is not a place to store this extra boost so it really doesn't have the effect like the other engines. Yes it makes the engine a little more efficient, but doesn't give the engine the "Boost"


The crankshaft ring makes this down stroke of the piston compress a smaller volume so it makes this charge more high powered and as a result makes more power in the engine. Depending on the engine 300-400rpm difference. This is just from the crankshaft ring.

The airbox or air chamber makes use of the super charger effect and this adds another couple hundred maybe as much as 200-300rpm in performance.

My good Buddy Greg Frohreich used to make after market airboxes for the 120NC's Basically you remove the intake pipe and replace it with the chamber. This allowed the engine to store and make use of that boost. It was effective. It would not give you a full chambered performance but it would improve it.

So the answer is technically yes, functionally well......if the engine is not getting the boost is it really a supercharger?

I suppose in the strict sense yes it is.

Troy Newman
Team YS

RE: YS 120 NZ Supercharged dos and donts
 

Hi

Ive received the YS but it has no instructions with it and it seems to have 2 nozzles on the front of the crancase what are those for and it doesnt seem to of come with a check valve? Any ideas?

Thanks tim

RE: YS 120 NZ Supercharged dos and donts
 

You do need a check valve. It is required for the engine to operate properly.

I sent a reference in an earlier post to the Pro build UK site with some directions.

again here it is.

http://www.probuild-uk.co.uk/factsheets/ys_engines.php


The two fuel ports on the front of the engine are for number one fuel supply. This is the port on the exhaust side of the engine.

The one on the needle valve side of the engine up front is for the pressure back to the tank.

Here is a photo of a 120FZ manual. It should explain it a little more clearly. Also in the drawing there are two fuel nipples on the needle valve side of the engine. One is at the carb near the needle Valve and the other is on the side up near the front. A section of fuel tubing must connect these two ports. This carries fuel from the regulator to the Carb.

Troy Newman

RE: YS 120 NZ Supercharged dos and donts
 

That photo didn't work well.

you can also go to this website and get the manual for the 140 Sport engine the hook ups are the same.

http://www.yspartsandservice.com/pdf/FZ140s.pdf

Troy Newman
Team YS

RE: YS 120 NZ Supercharged dos and donts
 

Thanks alot again Troy for all your help!!!!!

RE: YS 120 NZ Supercharged dos and donts
 

Hi Troy,
I have a YS 120 NC I bought from a friend. The engine starts well and transitions to wot fairly well, rolling the throttle, not all at once. The problem I am having is on 15% Cool Power Pro Pattern is after it warms up after starting it will pre-detonate and spin off the prop. I went to 20% Pro Pattern and it runs really well, however at times it seems as thou it has detonation, you back off the throttle it will stop, slowly increase the throttle and it goes to wot with no problem. I am running a 16x8 and tops out at 8475rpm, I backed down the needle to get 8175-8200. Idle is spot on at 1900-2000. My question is should I go to 30% to prevent the detonation at times, or do you have another solution or am I just doing something wrong? I adjusted the regulator as per the manual and idle seems really on the mark. Your help would be appreciated.
Thanks
Ed

RE: YS 120 NZ Supercharged dos and donts
 

Regulator is too lean.....


Also don't try to throttle it up hard right when it first starts up. It needs to warm up slowly a slow roll on for the throttle when it starts up froma cold.


But richen your regular a little bit...Like 1/8th at a time. Rich is (Out or CCW)

This should saolve the detonation problem. Another option is perhaps the check valve is not working quite up to par. It could be stickign a little and not allowing the pressure to flow. Try pumping raw fuel through it to clean the gunk out.

You don't want that detonation problem....it will break parts.

So beware of it and richen your regualtor screw a little at a time to get rid of it. On the 120NC and other engines without the air bleed screw on the throttle barrel....you have to walk a fine line between too rich for the idle and rich enough for the mid range. Its a tight band but its there just make small adjustments.

When you get it set properly the engine will be a little bit rich on the idle and load up when its started up from cold. But as the engine gets up to temp the idle will be just right and it won't quit in the air.

the 20% Pro Pattern will work well for you I would suggest it over the 15% for sure. You don't need 30% but it does perform better in the idle and transition.

Your problem now is its too lean on the regualtor and or the tank is not up to good pressure....so do the check valve thing and then start richening the regualtor to stop the detonation.


Troy Newman
Team YS

RE: YS 120 NZ Supercharged dos and donts
 

Thanks for the quick answer, I saw that you were online. Super! I will try your suggestion, that is what I had in mind but not sure, so you answered my question. I am gonna put it on an UltraRC Katana Extreme. They call for a 140-160 but I am not into exotic 3-D and the power this thing has is awesome and sure it will fly it for what I need which is sport flying and trying to learn patterns. The only thing I am worried about is the fuel consumpsion, it is hungry and loves fuel. But I have a 20oz tank in the Katana which should be ok.
Again thanks for the advice. Will post results!
Thanks again
Ed

RE: YS 120 NZ Supercharged dos and donts
 

Oh normal flying meaning not full throttle non-stop in a flight...the 120's on a 20oz tank will go an easy 13-15mins. You should have plenty of flight time in that application.

I'm running 170DZ's in my pattern models with 20oz tanks and I can regularly go 12-14mins. Now I rarely go to full power if ever when its calm. But the 170's and the DZ's in general take a much bigger gulp of fuel for every time they fire.


You should be golden.


If you find yourself a little low on power there is always the 140Sport which would be an upgrade. The engine works the same as the 120 you have and its a drop in replacement. The 140 is just a slight bit lighter than the 120 but the difference is very small less than 1 oz. However the power will go up 15-20% over the 120NC you have. Just something to think about if you are looking for more power. My guess is you will be pretty Happy with the combo you have. Work on keeping it light! Lots of things contribute, wheels, fuel tanks, battery packs, switch harness, even extra fuel tubing....You can replace long runs with 1/8" aluminum tubing and this saves lots of weight.


Happy Flying

Troy Newman

YS engines
 

Troy, are you still around? I know this thread is pretty old, but I read through your tips, and your advice has opened my eyes and is very helpful. I love YS engines and the power they produce, but they can be hard to adjust correctly if you don’t know the differences in these and other 4 strokes. I’m sure to have more questions for you, if you are still around. If there is a better way to contact you, please tell me how. Thanks!