lost compression

13 replies to this topic
  • bdruff

Posted May 27, 2009 - 03:37 PM


My bike pretty much sat in a hot garage for a little over a year with gas in it. I've only started it a few times during that time and rode it down the street and back and didn't have any problems. The last time I rode it was about 3 months ago. I replaced a clutch cable, test drove it down the street and then left it.

So I was thinking of taking it out this weekend and wanted to make sure everything was ok. I wouldn't start. I used some starter fluid and got it started pretty easily but wouldn't idle. I didn't need the started fluid once it started the first time. I was able to get it going but it kept cutting out and stalling and then was hard to start. I could get it to idle if the choke was on but not without.

Then it died and I couldn't get it started. I found the fuel line between the tank & carb was cracked. I figured air must be getting in the line. I replaced it but it still wouldnt run. I could spray starter fluid in from the air filter and it would start but then die.

I couldn't get the spark plug out but knew that was part of the problem but I also thought the carb might be clogged up. I took it apart and cleaned it then put it back on. I didn't take off the tsp. Still wouldn't start.

I could get it to fire with starter fluid but it wouldn't start.

I got a tool i needed to take out the spark plug and the hexagon and metal shield were corroded pretty bad. The nut and the electrode looked good. I cleaned it with a wire brush and put it back in.

NOW THE SCARY PART!! I tried to kick it but it felt like I had already pulled in the compression lever. I tried it again and it kicked thru. It always stops when at top and I have to pull the lever, kick it down a little, let it up and kick it thru. Now... I can push the kickstarter down with my hand. Its not easy but before it was impossible. And it still wont start.

Im worried that starter fluid was a bad idea. Ive used it forever and never had a problem.

What else could it be or how can I fix it?

  • ww44wrf450f

Posted May 27, 2009 - 04:17 PM


I see from your other threads that it's an 01wr426 correct?
If you have little comp. I would guess that it's time for some head work, new ti valves, rings and new piston?. Not to familiar with the 01. you need to check the valve clearance and pull the head and see?
And allso I would not use st. fluid.

  • chevy power

Posted May 27, 2009 - 09:12 PM


I think you should clean your carb, your pilot circuit is probably plugged, old gas does nasty things.
Pour a few drops of oil in the cylinder through the spark plug hole.
And it should fire, I bet the starting fluid washed the cylinder of oil.

  • rufusz

Posted May 27, 2009 - 11:42 PM


Did you put the spark plug back in correctly? Check if it is tightened and/or broken? If you take out the plug, you can push down the kickstarter with your hand, and you described the same thing...

  • Frostbite

Posted May 28, 2009 - 06:38 PM


What Rufusz said. It seems that your bike suddenly lost compression when you removed and replaced your spark plug, so the most obvious place top start is an improperly installed spark plug. Also, cleaning an old plug may help, but why take a chance - buy a new one. It also sounds like your carb needs cleaning.

  • bdruff

Posted May 29, 2009 - 09:18 AM


I've been reading thru a lot of posts on here. I bought a new spark plug. The spark plug threads in good. I dropped a few teaspoons of oil down and left it over night. The compression came back but wouldn't kick over. I pulled off my carb to double check everything was right. I put it back together very carefully and made sure everything was secure & tight. I kicked it several times but it doesnt fire and the compression seems to lessen as I kick it.

I'm reading all the posts here but I don't know where to start.

My next plan is to make sure I have spark. But even if I do, why would I be losing compression?

  • bdruff

Posted May 29, 2009 - 11:38 AM


it has spark.

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  • bdruff

Posted May 29, 2009 - 12:16 PM


after doing some more reading I smelled the oil. 90% sure it smells like gas. I'm a newbie reading out of a service manual but this is a bad thing right?

  • bdruff

Posted May 29, 2009 - 04:45 PM


I'm working on this and posting as I learn more. a little nudge in the right direction always helps. I changed the oil and the compression felt better. it still won't kick over. with the choke pushed in, it seems closer than with the choke out. I kicked it with the choke in and it almost fired up but then the compression started to lessen...not gone but I could kick thru again. a few kicks and the compression was back. don't know what to do next

  • rich1167

Posted May 30, 2009 - 06:27 AM


If your compression gets better when you put oil in the cylinder. It's typicaly a sign of worn piston rings. You should find a compression gauge and test your compression per the manual to be sure.

  • bdruff

Posted May 30, 2009 - 02:45 PM


I've never done any major engine work. I was able to take apart the carb following the manual.

What would cause the rings to go out. It was working fine untill I took off the carb. It wouldn't idle without the choke but it had good compression.

Could using the starting fluid have caused the rings to fail?

  • bdruff

Posted May 30, 2009 - 03:25 PM


This is killing me... literally its freaking hot and I'm tired of kicking this motha. The compression is strong untill I start kicking it. Then it seems to go away. If I let it sit for a minute, it comes back. ***? I've been reading all the posts and it seems that it can be anything. I don't have the money or patience to take it to the shop.

  • ww44wrf450f

Posted May 31, 2009 - 05:57 PM


If your tired of kick'n, get 2 buddy's to help you try in bum start it in 2nd gear, if you get it to run, great, but if it still has the kick start issue after the fact, you obviously have a comp. problem!

  • bdruff

Posted May 31, 2009 - 06:05 PM


Thanks for all the help over the years. I fixed it so I thought I'd contribute what I could in case someone has a similar problem.

I replaced the pilot jet which helped it idle way better once I got it started but it was the pilot screw underneath. The one you are NOT supposed to change. I guess I didn't put it back where it was supposed to be. Also the idle screw was way too far out.

It took me some time turning the screw on the bottom and adjusting the idle screw but its idling perfect now and has great response.

New plug
changed oil
new pilot jet
running like a champ.

Good thing I didn't tear into the engine.

thanks again


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