01 426- Low Compression -help!!

10 replies to this topic

Posted June 09, 2005 - 11:22 AM


We went to go riding last weekend, had a helluva time trying to get my 01 426 going. Finally did but it didnt want to run off choke,died after about 5 minutes and wouldn't restart. The compression is now about half a of what I'm use to. Does anyone have any ideas regarding compession before I tear into this mess? :)

  • jamieyz426f01

Posted June 09, 2005 - 11:25 AM


your decomp might be stuck out(constant decompression!) sheck the cable routing and if the cable has frayed.


Posted June 09, 2005 - 11:40 AM


I should have added that it was the first thing I checked-took out what I could,it all looked fine, cable like new-

  • MichiganMXer

Posted June 09, 2005 - 11:53 AM


Valves, timing, rings? Pretty much the top end? Do you have any smoke coming out the back, were there any hints or symptoms before this happened or was it running perfect to just shit in 5 mins?


Posted June 09, 2005 - 12:14 PM


Ran good a week earlier, only ran on choke for 5 min. Now it kicks over weak, like a TT125- (low compression)

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  • MichiganMXer

Posted June 09, 2005 - 12:19 PM


Try changing the plug man. It could be the cheapest fix out there.

I lost compression and it came back after a plug change.

  • jamieyz426f01

Posted June 09, 2005 - 12:20 PM


yea maybe the seal washer on the plug has gone kapoot??


Posted June 09, 2005 - 12:44 PM


We tried a new plug too that morning, no such luck. Does the decomp valve maybe have a seal that could break down?

  • CRFThumper

Posted June 09, 2005 - 12:51 PM


Sorry dude but there are a 100 things it COULD be!Rings valves,gaskit,decomp the list goes on and on.If it was running fine and then all the sudden you lost squeeze then maybe valves but thats just a shot In the dark!

  • grayracer513

Posted June 09, 2005 - 02:03 PM


If you have lower than expected compression, it seems like the first thing to do would be to check the valve clearances.

  • cbff33

Posted June 16, 2005 - 06:37 PM


I had a compression problem last fall...it turned out to be a piece of carbon that broke loose and wedged in an exhaust valve.

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