kx 500 surging

[clinton]

Hello all.I don't post much but I do alot of reading on this site and it is very helpful.I have been given a 1992 kx 500 I got i running but when i ride it it runs fine 3/4 throttle or so and when I let off the throttle still in gear it surges.Any help would be great never had one do this before.

[6 Riders]

Explain "surges"...goes faster? The throttle doesn't release?

[clinton]

goes faster with the throttle almost closed.

[6 Riders]

sounds like the needle is sticking. Clean the carb up and see what happens.

[zz3gmc]

Could be an air leak at the reed cage gasket or possibly the crank seals. I had a 88 KX500 that had a air leak at the reed cage and it would surge/run on when letting off of the gas. My 04 KX250/500 hybrid doesn't do this and runs near perfect.

[clinton]

Thanks I have been planning to check for air leaks when I get time.I read on the kx forum that it is common for the kx 500 to surge like this.I don't like that.The 500 and I will part ways if I can not stop it.

[s10gto]

You can also try to turn the air-bleed screw in. My YZ would surge when off throttle and idle. Turned it in a 1/8 a turn and was fixed. If it helps but doesn't fix it make sure the pilot jet is super clean. Good luck!