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PW50 Compression #'s?

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So my son's PW seems to be getting a little tired. It runs decent when warmed up and going but it does take 3 or 4 kicks to start. I replaced the plug about a year ago, been through the carb and cleaned it, air filter clean etc. I decided to do a compression test before I through some money into since he wants to move up to a 4 stroke. 80 psi was the highest number I got. So according to my search, I should have at least 100 psi. Sounds like I need to find piston and rings.

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did you do the compression test with the throttle all the way open? If so, then its time for a new top end.

yes, you should have well above 100psi for a good running motor.

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The PW line produces incredibly low compression numbers, 80 PSI might be as good as you're going to get. Traditional knowledge says that it's time for a new top end job, but you may find the number doesn't change.

Does it feel normal when you kick it? If it runs, just run it. If it makes you feel better, put a new top end in it, they're not that expensive, but don't be surprised if your numbers don't change - it's happened to another member here, 80 PSI before, 80 PSI after. It's only 6.0:1 compression ratio.

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did you do the compression test with the throttle all the way open? If so, then its time for a new top end.

yes, you should have well above 100psi for a good running motor.

Yep, I held the throttle wide open. I talked to a guy at a machine shop to see if he could look over the cylinder. He said if it still runs good, let it go. Testing the compression on these little bikes is subjective. If you have a long hose on the guage, that could have almost as much volume as the cylinder.

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Yes, that's why you kick it until the needle stops moving. There's a valve on the cylinder side of the hose that doesn't allow the pressure to flow back into the cylinder, so you're only losing a small fraction of the actual pressure because the spark plug takes up more volume than the gauge adapter does.

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