happywing

Just got my first nitro vehicle yesterday. It has an RB C5 in it and I'm going to fire it up for the first (first for me) time this evening. Any advice for someone who's starting a nitro engine for the first time? Looking for stuff like how to prime it? What if it floods? where should I start the needles? I have no manuals, so any other info about the C5 would be appreciated. I'll be running 25% nitro. any advice on the best plug to use?

mkincy

to prime the engine hold your thumb on the exaust while you bump it a couple of times, till you see fuel travel thru the lines into the carb. if its used the needles are probably pretty close to the corrects settings, but if not, the rb stock settings are high needle = 3.5 turns out from closed, low needle= 5 turns out from closed. if it floods rmove the glow plug and bump it a few times to clear the fuel from it.

good luck, have fun. the C5 is an awesome motor.

MassiveMods

Pre heat engine with a hair dryer
Start it
tune for clean 2 stroke
start to play with it straigh away
dont go ballistic straight away but dont be afraid to get it hot

Heat will allow the engine to run in properly.

slodsm

My Feedback: (1)

So you are saying the engine is already broken in, just by someone else right?

If so, don't touch anything, just fire it up and have at it. If it is brand new, still don't touch the needles, heat it, make sure you have a full charge on your starter box, prime it and go. Don't try to break it in under 190-200 degrees, it's not healthy.

As for plug and nitro, if it's new, the stock plug should last you quite a while and use whatever nitro you can get as long as it's not one of the less forgiving "platinum race blends" because those have a lot lower oil content and will not be good for your first motor because you will make some mistakes with it.

If used, try to keep using whatever nitro he was using before you and stick with either the same plug or the RB concepts #6 plug which is what RB recommends.

mkincy

its a used engine.

happywing

Thanks! I ran it today. Like slodsm suggested, I used the #6 plug and just ran it close to how it was set up by the previous owner (yes, it's used and freshly broken in on the bench according to the previous owner). I just richened a quarter turn for safety. This is my first nitro, but it seemed good to me. I think it may be a little lean. In the straights, it got up to speed quickly, but seemed like it had more if there was more fuel for it. Kinda sounded like it was winding out. Temp was right around 200 degrees which is good, but I'm still going to try and richen it and see what happens.

Hincappe

most important, run OUT the fuel and put after run oil in it.

cable tie the air filter and change air filter regularly

most newbies destroy there first engine coz air filter pop off or thire engine full of rust. speaking from my own experience []

andreas78

You can download the exploded view of the C5 here:
http://www.rbproducts.com/explose/RB...PT/01005-C.pdf
This might be useful if you need replacement parts in the future. The factory needle settings are stated there, too.
There are also a bunch of good tips on the RB website:
http://www.rbproducts.com/mainEn.php?part=Support
Have fun,
Andreas

slodsm

My Feedback: (1)

If it's already fully broken in, don't try to make it any colder. I would run the engine from 200-220 or so and mainly tune by sound.

RB motors like to be a little fat on the bottom and scream up top. They are a wicked motor and all I run in my 1/8 scales for the past 3 years.

happywing

slodsm - I wish I could tune by sound, but this is my first nitro. Right now:

Idle: When I bring it in, it idles high for a few seconds and then drops RPM to a rumble
Low speed: It seems to take off pretty good with no sputtering
Mid speed:It gets to mid and high RPM very quickly and then levels off
High speed: I don't think the top speed is that great. It's reving high but not going fast.
Final note: It could be a perception thing on my part, but it seems like if I'm in a long straight, It'll go faster if I let off and then punch it again.

What do you make of that? I'm not sure if it's well tuned or not.

This engine does seem to run quite cool (from what I've read). This one also has a big King Headz cooling head on it. What effect does a more efficient cooling head have on running temps?

kx250ryder

You have the same problem I had when I started. You are new to nitro, and don't know what a properly tuned engine should sound like.

Warm your car up on a stand with all the wheels off the ground. Once you have it warmed up, give it full throttle and lean the high speed needle until the engine reaches peak RPMs. Do this a couple times, and if it stops gaining RPMs, or starts to hesitate or stall, you have gone too far. Do this quickly, because these engines don't like to be wide open with no load for long.

It may take a couple tries, but this will give you an idea the pitch. The first time I heard one running right, compared to what I had been running, I thought the guy was trying to blow his motor up. They are pretty high pitched when race tuned. That will get you in the ball park.

You can get your low speed needle set by bringing the car in and pinching and holding the fuel line until the engine dies. It should die within 5 seconds or so, and not increase much in RPMs before it does. If it increases greatly, its too rich, if it dies without increasing at all, its too lean. Once those are close, set your car on a stand, and make the idle as high as possible without making the wheels spin.

Then, just fine tune the engine to make sure you are getting clean acceleration all the way to top RPMs for your longest straightaway, and still seeing smoke between low-mid RPMs.