Skidoos check your PM's.

Also thought this might be useful for some.

Brandon Melton
Yeah sure thing, you are right, it's often the small stuff and even the simple things can get a engine to run great.

I'll go more in depth how I tune the motor, there are all different ways of how people break it in. This is how I have personally broke in my Reedy engines, and they all tune well and perform for a long period.
-always preheat before starting it up for the first time
-wrap the head with something like foam, foil, a sock or something to retain heat.
-idle just ONE tank through the engine (just to oil and seat the parts). LET COOL after first tank
-PRE HEAT engine again-on the second tank I am running the engine on the ground, with the HSN a little rich for lubrication but lean enough to get temps up to around 240. Run the whole tank out using idle to 1/2 throttle bursts. let cool again
-Keep doing this for 3 tanks, then for tanks 5-8 I keep it at the same HSN setting but now I am making about 100ft pulls of wide open throttle (temps still staying around 240).
-after 8 tanks I put a race tune on it and try to kick some butt
-biggest thing is making sure the engine cools after each tank, and then preheating it before the next start up. I usually preheat the engine for the first 1/2 gallon.

TUNING

I will say that on all 5 engines I have ran, I have never used a carb or back plate sealant, and have never had an air leak or funny tuning. Some people swear by sealing an engine but I have had good success without doing it.

I actually prefer to tune from the bottom end first, and can usually get it really close on the box before hitting the track. Here's how I go about a tune when I get to the track.

1.) Start engine and rev gently for about 2 minutes to get some heat into the engine, always tune the engine when up to close operating temp.
2.) I clear the engine out when a couple solid (not death revving) revs then listen to how it comes down to idle, wait about 5 seconds and hit the throttle.
3.) I look for a steady smoke trail and a steady clean pull from the bottom end. You don't want heavy smoke at first tapering into a faint trail. The engine shouldn't hesitate with a rich or lean bog. Should have a crisp sound with steady smoke.
4.) If the engine blows lots of smoke and hesistates to start pulling, lean the bottom end until you get what’s described above. If the engine doesn't blow smoke and stutters to accelerate, richen the LSN until the desired setting.
5.) A KEY indicator of having a close tune on the LSN is listening to the engine come from a rev back to idle. With the proper glow plug and a properly tuned LSN, the engine should almost immeditaly achieve idle speed after a rev on the starter box or on the track. If the idle hangs up, then slowly comes back to idle in "steps" you are too rich on the LSN, probably noticing a lot of smoke as described above. If the engine tends to run on and maintain a high pace without ever coming back down, the LSN is too lean. ALL THIS IS ASSUMING THE IDLE GAP IS SET CORRECTLY (which is around .6-.7mm.)
6.) Once the LSN is where I want it, I will tune the HSN on the track. Assuming climate hasn't changed dramatically since the last time I raced, this is usually only 1 hr. either leaning or richening for optimal tune. If it's the first time with a new engine, it may take a couple adjustments to hit correctly. A proper tune on the HSN should pull hard until the end of the longest straight, but never totally run out of smoke or "run on" at the end of the straight. If you have properly set the LSN and the engine runs on after long straights, the HSN is too lean. If you see a little smoke, and it doesn't run on, you are very close.
7.) After break in, if the engine runs and performs well, and all driving characteristics are as they should be, I don't pay attention to temps anymore. If you have it tuned properly, the temps will fall where they should. You will learn to trust your tune. I could just about tell you within 5 degrees what it would be before a pit guy checked it, LOL.
8.) After setting the HSN on the track, I will then just double check the LSN sound and response after a tank run before shutting it off after it's at full operating temp. Make any minor (if needed) adjustments, and then it's usually good for the rest of the day, unless the mains go into night fall.