General air leak question

[Sloppyslopster]

Hey. Just want to ask what you guys do to properly detect air leaks. Like where on the engine should I look and what fluid one should use to spray. I tried using wd-40 but I’m not too sure how good that is.

Pretty sure I (still) have a leak. Bike will die down to low rpm at idle and when I blip the throttle it revs real high up. Also has a hard time keeping idle and tuning is a nightmare.

Thanks for any help!

 

[Wyvern]

Hey. Just want to ask what you guys do to properly detect air leaks. Like where on the engine should I look and what fluid one should use to spray. I tried using wd-40 but I’m not too sure how good that is.

Pretty sure I (still) have a leak. Bike will die down to low rpm at idle and when I blip the throttle it revs real high up. Also has a hard time keeping idle and tuning is a nightmare.

Thanks for any help!

Carb cleaner is probably the best bet, but brake cleaner also works (in a pinch)
Most common place to leak is between the intake throat and carb, but the bearings can leak too, as well as the case.

 

[GW's Motorized]

Base gaskets, case gaskets, head gaskets, manifold gaskets, and the carb connection on the manifoldis where most air leaks are. Carb clean or brake clean is my go to.

 

[Wrench]

Base gaskets, case gaskets, head gaskets, manifold gaskets, and the carb connection on the manifoldis where most air leaks are. Carb clean or brake clean is my go to.

& crank seal

 

[Chainlube]

The very best for checking for leaks is a little mist of water. It's not volatile and burn your place down. The engine will just die and the water will evaporate quickly on a warm engine. Another place for an air leak is the spark plug, but that is more of a compression issue. High idle is an air leak usually from the carb to intake or intake to cylinder, also check the cable connection at the top of the carb.

 

[ImpulseRocket]

I suggest not using carb and brake cleaner around rubber seals as it causes the rubber to swell and can mask the problem. A mist of water as Chainlube suggested works just fine, and it has the added benefit of helping cool your air cooled 2 stroke as it sits still running

 

[Sloppyslopster]

I suggest not using carb and brake cleaner around rubber seals as it causes the rubber to swell and can mask the problem. A mist of water as Chainlube suggested works just fine, and it has the added benefit of helping cool your air cooled 2 stroke as it sits still running

Sounds good! Thanks guys. I'll have a look tomorrow and see what's up. I'm assuming its something minor tbh. I think seals are fine, I tried my best to bullet proof the life out of them even to the point where I bought viton crank seals and upon installation I put a light-ish coat of gasket maker on the outer bit of them so they REALLY seal up good.

 

[Alpenflitzer]

I am using starting help spray. If there is an airleak the engine will get more RPM. This does not harm anything.