2001 Zr800 Pistons - Snowmobile Forum: Your #1 Snowmobile Forum

merccrazy · 10-30-2009, 09:30 PM

Hi,new to this site and did a search but no go.I want to freshen up my ZR800 twin with 4500 miles on it.The compression was 130 in each hole last year at the start.I want some feedback on which piston to use.
1. wiseco
2. spi
3. oem cat pistons

Thanks for your input.

Scott

Mrdman2442 · 10-30-2009, 10:48 PM

130 psi is still good, no need to be fixin it.

merccrazy · 10-30-2009, 10:57 PM

Shouldn't I be concerned with the skirt breaking with that many miles?

Mrdman2442 · 10-31-2009, 03:02 AM

Piston skirts only break when there is wear or damage to the cylinder and/or piston. Rebuilds are usually needed once compression drops below 110 - 120psi, 100 seems to be the mininum to start it. 130psi shows everything is still good and not to worry about it.

**kccats** · 10-31-2009, 10:18 AM

If that motor hasn't been freshened yet then it has wear! I have used the Wisco and didn't see much improvement! The one thing to do is to have the skirts coated!

merccrazy · 10-31-2009, 10:43 AM

Shouldn't the compression be 140psi on a fresh rebuild after breakin.I would rather be safe than sorry.A little preventive maint. goes a long way.I know I have been working on boats for a living for 20+ years.I believe it needs to be looked at and at least rerung but if it"s down that far it's going to get new slugs.Just want to know which pistons people are having luck with in this motor.Thanks

Empire087 · 10-31-2009, 11:22 AM

I got the 02 zl 500 and I'm using the coated spi pistons that have worked well.

JDS · 10-31-2009, 12:27 PM

I agreee with SPI.

**kccats** · 10-31-2009, 04:02 PM

Pull it apart now and all you'll be out is a set of base gaskets!