125-200cc Exaust Leak - Affecting Jetting

Hey everyone

My bike's developed a leak where the exhaust meets the motor, and there's spooge leaking all over.

Question: can such a leak cause the motor to run rich?

The bike seems to be running richer all of a sudden and it coincided with the leak so I'm trying to figure out if they are related?

when the exhaust is leaking the total amount of air pushed through the motor would probably less at the range where the pipe is tuned for and that's probably also the rev range where you like to ride the motor in

if less air comes in the motor the percentage of fuel in the mix will increase and would result in running richer

Robert-Jan

Yeah, pull the pipe and see wtf is going on. While the pipe is off shine a light in there and have a look at your piston and rings.

An clean all the soooge off then high temp silicone the header back on after replacing the o ring.

Thanks for the replies, everyone.

Will try re-sealing the pipe. These bikes (2012 WR 125) run a single metal o ring, right?

No mate. They run a normal type o'ring in the groove on the pipe and a steel washer where the pipe seats against the barrel (at the end of the pipe).

My 150 was messy at the exhaust manifold. When I did the 165 I found no steel washer, so installed a new one with a few blobs of hi-temp silicone to hold it in place. New o-ring too, no more mess so must be sealed up well.