no compression....sometimes. why???

2 replies to this topic
  • thumper4life

Posted June 20, 2002 - 07:28 AM


took subframe and carb off to do bk mod and jet it, my dad decided to unscrew the idle all the way. so after we got it back together we tried to set the idle back to where it should be which resulted in me kicking it about 40 times.
but my question is, sometimes when he would turn the idle up after another failed start, i would go to kick it and there would be no compression, well a little bit but i could kick right through it. its fine now and works fine and the BK mod rips, but i wanted to know WHY there was no compression sometimes after turning the idle up

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  • JSTheJack

Posted June 20, 2002 - 08:10 AM


You know, I posted that same question about a week ago when I read other messages about no compression. I'd bet the exhaust valve with the compression release is not totally seating, or there is carbon built up on the exhaust valve seat.

That has got to be the only rational reason for the loss of compression that later returns. I can't believe the valves would stick unless they're bent...I mean, valve springs are really stout.

  • thumper4life

Posted June 20, 2002 - 08:35 AM


yeah, after searching on this site (that search comes in handy AFTER i post :) ) i found that a valve was most likely sticking, and your reasoning is perfect because my bike was running SUPER rich and there was a crap load of carbon in the header. and when i was flushing it out with my hand after sprayin all the gas in it after the bk mod and flushing it out with no plug in it, it became hard so i hit the comp release and pushed it through a few times. so that and the carbon build up could be the reasons it was sticking. at least its fine now :D

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