stuttering on after chopping throttle under a load

[overbore]

I think that it is caused by detonation from heat after a
heavy load pull on the engine,but cant find a air leak or
anything that would cause this symtom.So I would like
to make sure I understand whats going on with there being
too much fuel left and its burning on and on after chopping
the throttle with it being to hot.I have adjusted the air screw
out on the 01 rm250 4 turns with the choke air screw closed
all the way to shut off that air and it seems better,but that
would contradict a lean condition by giving it more air and it
gets better,so I just need to understand in theory what causes
run on like this.Maybe something I havent thought of.
Any Ideals on what causes this as when we go to hare
scrambles I know that I have heard other bikes do it,but just
not as bad and as long of a run on.
Thanks for any responses
overbore.

 

[overbore]

no ones bike has ever run on like it is running lean.
Why does a engine run leaner as it gets hotter?
need to figure this one out.
Any Ideas
overbore

 

[elf]

Its been my experiance that a bike jetted a little rich gets richer when its hotter. I also know a bike jetted on the lean side will have higher temps in the combustion chamber, eventuly causing detonation. When you chop your throttle your getting very little fuel or air in your engine yet your engine is very hot and the rpms are high. Thats a situation where you can damage your piston or seize it up. mixing some race gas in with your pump gas would help, Or bliping the throttle while your slowing down to get some gas/ oil into the engine will help. Or you can try richer jetting.

 

[overbore]

thanks

thanks for the response elf,but I cant hardly blip the throttle
on a steep hill or incline.I guess what I am asking is to
understand on exactly whats causing this or is my ideal
right so I can come up with a plan to fix it.When you chop
the throttle then is there only gas thats coming thru what
ever it takes to idle I would think.Is this combined with the
air being brought in at a faster rate since the engine still
hasnt come all the way down cause the fuel air mixture to
be super hot and explosive causing it to detonate?or do you
or anyone think that its caused by to much gas leaking thru
some other jet causing it to run on?I just dont know and want
to know what is causing it so I can fix it.
Anyone.
overbore ;)

 

[elf]

I would think.Is this combined with the
air being brought in at a faster rate since the engine still
hasnt come all the way down cause the fuel air mixture to
be super hot and explosive causing it to detonate?
overbore ;)

Right!
You need to run richer on the pilot jet to help the problem.Maybe even richer on the needle. You dont need more air just more fuel.


Too much gas wont cause detonation.