130PSI Cold compression

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130PSI Cold compression

Postby Lumpy » 03:49 pm Aug 08 2017

new to me 2000 KDX200. Just prepping and cleaning and adjusting everything for the woods . I know that 130 PSi is certainly within range but when does one begin to questions " should I do A top end "?
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Re: 130PSI Cold compression

Postby bufftester » 05:05 pm Aug 08 2017

I do it when I start to notice a difference in the bike, which usually is at around 25% of the new piston/ring compression value. Some do it every season if racing, I know of one guy who has a 2000 220 that is still on the original piston despite my warnings and he probably has 500+ hours on it. For my last one compression with the new top end was 152 psi, and when I did my rebuild it was at 118 psi and I could feel it wasn't pulling like it used to. Don't know where you are located, but 130 psi at this time of year I'd ride it and check again at the end of the season since you're within around 10% of normal. I've seen KDXs run with less than 100psi, though they usually are having starting issues by then.
2001 KX/KDX 220 Hybrid, 1999 KLX 300, 1995 RMX 250, 1992 GSX-R600, 1993 GSX-R750, 1994 GSX-R750, 1995 GSX-R750
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Re: 130PSI Cold compression

Postby doakley » 02:18 pm Aug 09 2017

A good idea is to check compression periodically so you begin to create a history for the bike. Also try to use the same gauge each time if you can. My rebuilt,with recoated cylinder, was at 161 cold after break in.
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