problem with decompression in wr426

[tshe1]

i have wr426 2001 and when i was trying to make it works it seems to have problem.

i pulled the decompression lever and hit the kickstart, it looks like the exhaust valve jammed open because i was able to hit the kick again and again without puling the decompression lever.

finally the bike started, turned it off and started again, but puling the decompression lever is going pretty hard.

1. what can be the reasons for that?

2. do you think the bike harmed from this attempts to start it, and finally starts it?

3. an explanation of how the decompression works in that bike if someone knows?

thanks allot

[byggd]

When you pull the decompression level you are holing open the right side exhaust valve. If it's hard to pull or is sticking open I would recommend pulling the valve cover and see what's going on in there before you do some damage. You can check your valve clearance at the same time

[SJMC_DON]

You either had the valve stick or the de comp cable stick. Happened to budddy once on his YZ 400 and never happened again.

Good Luck

[tshe1]

what was the problem in his bike and how he solved it?

it seems at my bike that the cable isn't the problem.

[tshe1]

can the problem in the decomp. can be solve by getting off the valve cover only?

[SJMC_DON]

what was the problem in his bike and how he solved it?

it seems at my bike that the cable isn't the problem.

Happened during a hare scrambles about 3 or 4 years ago. Bike stalled, he went to restart used decomp lever to find TDC, bike just kept kicking through without any compression. He sat and kicked for a 1/2 hour with no change. He started to push the bike out to the road and decided that he would try compression starting it when he got to a down hill. He tried, it did not start but his compression came back and he was able to kick start it at that point. He took it home, removed the head and found nothing wrong, valve clearance was still in spec, oil change verified oil was still clean and free of debris. He rode the bike for another 6 months without any issues and then sold it.

My geuss is that his, (and yours), decomp valve was stuck The cable is unlikely but worth looking at.

Good luck

[HamBonE_23]

Did this happen after a top-end rebuild or just all of a sudden it started doing this?

[tshe1]

it was sudden starting doing this. the engine is o.k and never did any problem

in running either at starting.

the problem came out after the bike set for two weeks.