Jan 3, 2007
My old steed that is an air cooled 2 stroke seems to be overheating really badly and boggoing down when its hot. Now it only seems to do it when i am 4th gear and plus. I cleaned the air filter, have a great spark, its getting fule and the carb is clean. Any help would be great thanks!

dirt bike dave

Sponsoring Member
May 3, 2000
Well, you would be getting more cooling air over the fins under those conditions. But your motor is sucking down fuel the hardest and generating the most heat when you are under sustained heavy load. So there is a difference between getting fuel through the line and getting enough fuel/oil for sustained high speed running.

Check to make sure the screen in the pet*c*o*c*k is clean. Make certain the fuel tank breather is unobstructed. If you are running an in-line fuel filter, remove it or replace it. And make sure your carb's float level is not too low. While checking the float level, make certain there is nothing obstructing the main jet.

If those things don't help, you might want to go up slightly on your main jet or add more oil to your mix so that things are better lubricated.


Apr 25, 2000
Just to clarify the previous suggestion. Adding more oil to the mix means less fuel is available to burn ( aka: more oil = lean fuel mix) so the engine temp may get worse.

What fuel were you using?
What oil were you using?
What mix ratio were you using when it ran hot?

Generally a hot running machine, has a worn piston ( beyond spec), or/and is possibly out of time/ignition wise...or could be running too low of octane rated fuel, or is jetted too lean.

Need more info to really help.

Jan 3, 2007
originaldirt, i was running Castrol super 2 stroke mix at 50:1. I ushally run AMSOIL full synthetic HP INJECTOR at 50:1. I also had to change the oil badly that day and i could not get a AMSOIL full synthetic that day so i bought really cheap stuff instead. So, i bought all my synthetic stuff yesterday and i am going to run that and see what happens. The jetting is not lean for the fact it was running perfect a week befor the oil change and different oil mix. Also, i run 95 Octane fule in my bike and i also just did the topend about 110 Miles back or so.


May 19, 2006
dirt bike dave said:
Check to make sure the screen in the pet*c*o*c*k is clean. Make certain the fuel tank breather is unobstructed.

We always hear about oil/fuel mix, jetting and the magical floats that somehow bend themselves. Yet ignoring this simple piece of above advise can absolutely cause nightmares.

Last time I had a problem exactly like yours, it was plugged vent on my fuel tank.


Feb 20, 2007
as for the overheating my it 175 did that and i sandblested the head and painted it with a thin coat of high heat fireplace paint it definatley helped
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