2004 Yamaha 800 XLT Compression

brick75

Petty Officer 1st Class
Joined
Apr 21, 2010
Messages
289
Hi, I'm looking into buying a 2004 Yamaha 800XLT. Going to see it this weekend and will be doing a compression test on it. Does anyone know what the ideal compression rating should be on this ski, or how to find that information?

If anyone has any other helpful tips on what to look for on this particular model, I'd appreciate it.

Thanks
 

Ernest T

Petty Officer 1st Class
Joined
Aug 29, 2009
Messages
367
Re: 2004 Yamaha 800 XLT Compression

For 2 cylinder 2 strokes you generally want to see 140 to 150 psi per cylinder and no more than a 10% difference between cylinders.

I'd ask about whether the power valves had been clipped. I'd also ask to see if the catalytic converter had been replaced with a "D" plate. If these things have not been done, then I'd consider doing them if you buy the ski. Deduct at least $150 from the price if these things have not been done.

I'd also want to know when the last time the carbs were cleaned or rebuilt. If more than 3 years you will probably also want to have that done...........subtract another $200+.
 
Last edited:

brick75

Petty Officer 1st Class
Joined
Apr 21, 2010
Messages
289
Re: 2004 Yamaha 800 XLT Compression

Thanks a lot for the info Ernest T. I'm fairly new to the world of PWC's. Would you mind explaining the significance and benefit to the power valves being clipped and the catalytic converter being replaced with a "D" plate?

Also, do you know if those things relatively easy to do for someone that is mechanically inclined?
 
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