AMGRacer

Yep thats an "overheat". But you will notice that around 15 or so minutes into a long race it happens. Basically the entire chassis and the entire motor becomes fully heat soaked. This takes around 15 minutes or so to occur. You will find that your bottom end will become very dull. It can be damaging. As your engine heat soaks it becomes leaner. When you make a fuel stop you lose all your back pressure as well which leans the motor a little, possibly contributing to the noise.

On a long race I always run the LSN a little richer than usual because it will lean out after around 15 minutes.

PSI Racing

InitialD,
Do you know all the ranks and number of posts to get that rank?

rodrigo1508

Hi InitialD could you please Can explain me more deeply your break in method, like what temps should I keep and details like that?
Thank You

InitialD

Yup. And I would increase the idle by about the same amount.

InitialD

No idea. <keeping mum>

Brett.w

ok i have jus tried to turn the fly wheel and it spins around 60 deg and the it is hard ot turn the next 30 deg and so on. I have taken off the head and the top of the piston is black, the flywheel seem hard to turn when the piston is comming to the top of the engine ( like the top is smaller than the bottom and it rubs) sorry for all the questions iam new to this engine tuning!

InitialD

It's tricky because the temps are pretty cool. About 50 to 60 degree C. When you get more and more tanks in, you may want to lean it more and more to get more wheel spinning and load to the engine. At the end of the day, you will find that the internal piston liner is polished.

Profoxcg

iTrader: (2)

how do you open an engine. Do I just inscrew the 4 screws on the back and close it when i am done? or do i need to take any special precations? or use any sealants?

AMGRacer

Sounds fine. I think the loss of power was a little warning by your engine that you were a shade bit lean. A properly tuned motor will run with the same power no mater how long you run it. If this happens again pull into the pits and get your pitman to richen the lower needle or middle needle a 1/4 turn (middle if it is too hard to get the lower one with body on).

Manticore

this is few of logical post i find on this thread !

Brett.w

Phew i thought i had done some damage then! just to clarify richen the bottom end 1/4 of a turn is turning the screw counterclockwise?

AMGRacer

Yes. I say 1/4 of a turn to be totally safe but mayby 1/8th would be sufficient you need to get a feel for your specific engine. I usually do the middle needle when I am in a rush since you can access it easily through the rear window.

If your motor still has pinch at the top when hot without the plug it actually is not even run in fully yet.

To do a proper compression test you can do this:

1. Remove the motor from the chassis and remove pipe.
2. Spray a little fuel into the exhaust port and turn the motor over once or twice.
3. Roll the flywheel over while holding the exhaust port up to your ear. You should hear hissing which then stops as the piston nears the top of its stroke.
4. Hold it still before it fully turns over. You should not hear any hissing for at least 10 seconds. Less than 10 seconds is still OK but the motor is no longer in its prime.

markp27

I can say only one thing........

markp27

Have you broke your D1...ehm, I mean digi cam?

markp27

On the subject of engine tuning.....I can get my engine tuned pretty ok these days, but one problem I often have is re-starting the engine when it is hot.
Does this indicate that the lower needle setting is too lean or too rich?

Cheers, Mark.