Compression Lost

2 replies to this topic
  • Snapper

Posted March 24, 2002 - 12:56 PM


I used my bike for the first time in three months (injury lay off) and found there was no compression - I could move the kick start by hand. I had changed the oil and checked the valve clearances, swingarm headset lube etc (one armed maintenance) but not started it. After checking front to back, decomp action, spark plug etc I noted the compression was getting slightly better each kick - clammy valve?

After about seven million kicks it started so I killed it and checked again, compression was back and it ran well, starting first kick.

Any ideas?

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  • Guy

Posted March 24, 2002 - 01:11 PM


:) GREMLIN'S mate.......No seriously it could well be a sticky valve, I allways make a point of bringing the bike to TDC when I leave it a long time, mainly so that there is no pressure on the springs, but also so that the chamber is sealed keeping out moisture, short of tearing into the head to check everything, I dont know what to say except keep an eye on it, Unless someone else has a different soluton??? :D

  • moorespeed426

Posted March 24, 2002 - 02:47 PM


I have had this happen twice tome on my yz426 after extended periods of sitting,just kick it through and get it started and it will be back to normal.It probably is a good idea to bring it to t.d.c. so the vavles won't stick.


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