02 decompression sticking at idle

[Kawboyz beware]

My buddy bike has a 02 and with the bike hot or cold and at idle or low rpm the is a distint noise that comes and goes, i can increase the rpm a 100 or so and it will go away. sounds like the decomp is sticking .. .sometimes wihile its makinfg the noise it will just stop on its own and all a sudden it back. do you think its the csource

[mojoe2878]

describe the noise as best you can and were its comin from and maybe someone can help.
have you even tried to free the decompressor by turnning the motor over with a socket wrench back and forth real quick? that usually does the job of freeing a stuck decompressor.

[pead_24]

Mine does the same thing at idle but soon as i hit the throttle it goes away then when i let it idle again bout 5 secs it doe sit again but i only noticed this when the motor was cold??

[chucked]

Mine did that and I replaced the cam chain tensioner and it went away, but it soon came back, when I had the motor apart I looked at the cam chain and it was waaaaaaaaay stretched, there was hardly anymore play in the cam chain tensioner.

[Kawboyz beware]

this bike has done it since day one . it only probaly has about 40 hr max and the bike is all stock

[mojoe2878]

Originally posted by Kawboyz beware
this bike has done it since day one . it only probaly has about 40 hr max and the bike is all stock
if its done it since day one then its probably the decompressor or the valves were not set properly from the factory. if it was valve it would do it all the time.
its more than likely the decompressor since they seem to have a problem with sticking and holding the one exhaust valve slightly open when its at low rpm's , like when it s idling. it will make a ticking noise.

[Kawboyz beware]

I checked and readjusted the valves after the initial break in. But the noise was still there. at a low rpm the noise will come and go at times. I really believe it's the decompression sticking. Next what would be the correct way to repair the decompression? I could just buy all the related parts for that assembly. but it looks like the spring may be the source of the whole problem.

[chucked]

Originally posted by Kawboyz beware
I checked and readjusted the valves after the initial break in. But the noise was still there. at a low rpm the noise will come and go at times. I really believe it's the decompression sticking. Next what would be the correct way to repair the decompression? I could just buy all the related parts for that assembly. but it looks like the spring may be the source of the whole problem.

try adjusting your idle really low, tell me if it goes away when it idles very slow.

[jhr400EX]

Mine has done that since the day I bought it... But it only does it whenever it is warming up. It never seemed to affect performance or anything after it gets warmed up.

[mojoe2878]

Originally posted by Kawboyz beware
I checked and readjusted the valves after the initial break in. But the noise was still there. at a low rpm the noise will come and go at times. I really believe it's the decompression sticking. Next what would be the correct way to repair the decompression? I could just buy all the related parts for that assembly. but it looks like the spring may be the source of the whole problem.
you could take it apart and see if something is wrong with it or you you could just ignore the noise.
you could also get a mild cam like a hot cams stage1, the hot cams dont use a decompressor so you wouldnt have to worry about it anymore, but the hot cams tick some what more than a stock cam does but its normal for it to.

[stang9gt]

Do the 05 400EX's have the decompression valve thing??? Would solve all my worries if they do!!