Mar 12, 2004
33
0
Has anybody had problems with their auto decompressor sticking or breaking? Are they adjustable? Every time I adjust my valves I check the decompressor to make sure it is not sticking, but I have not adjusted the clearance. The first couple of starts after adjusting the valves are like butter - it's easy to kick and starts on the first kick. Then, after the first couple of starts, it's like kick a Harley. The valves are in spec and the bike runs very good. Any help would be appreciated.
 

baker

Member
Feb 11, 2008
2
0
I am having the same problem.I rebuilt my 05 crf 450 with a wisco piston (standard com.) and had two intake valves (kiblewhite) put in my head.Now when I try to start the bike If I kick it hard the kickstarter will only go through part of the stroke and then will abruptly stop, but the bike will start if I use the old yamaha method of taking the motor to top dead center and then slightly past then kicking.All valve clearences are in speck as well as the decompression arm clearance.I cannot find much information on this problem and am about to take it to a shop.
 

_JOE_

~SPONSOR~
May 10, 2007
4,697
3
Sounds like the arm is hanging up on the 250. Once it starts the arm overcomes the spring tension and rotates the shaft to restore the lobe shape so the valves can seat. Maybe the spring is just worn out and it can't come back to rest once shut down.
 

_JOE_

~SPONSOR~
May 10, 2007
4,697
3
Looking at the setup on the 450 it seems similar in design just mounted externally at the end of the cam, and a seperate rocker. The rocker appears to have an adjustble tappet on the end near the valve. I'm sure there is a clearnce spec in your manual.
 

_JOE_

~SPONSOR~
May 10, 2007
4,697
3
Sorry about the clearance info baker, missed it in your post. Does yours use a spring to pull the arm back?
 
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