FYI SPI DUAL RING PISTONS FOR 800 CFI

[IQRIDR]

I have a set of the new 800 CFI dual ring pistons from SPI at my shop. This morning I compared everything about them but the weight, and the measurements are basically identical everywhere to the "revision a.b." 800 CFI pistons. Same taper, same skirt thickness, pretty much a direct clone. So now there is a $100 option instead of $185 at the dealer.

Thought this info would be helpful to many...

Also, SPI now offers a replacement 700 CFI piston that retails at $90 or so.

 

[SaskRMK]

I'm currently breaking in my 09 600 CFI with SPI Moly coated pistons and so far so good. Thanks for the good information!

 

[R44guy]

I have a set of the new 800 CFI dual ring pistons from SPI at my shop. This morning I compared everything about them but the weight, and the measurements are basically identical everywhere to the "revision a.b." 800 CFI pistons. Same taper, same skirt thickness, pretty much a direct clone. So now there is a $100 option instead of $185 at the dealer.

Thought this info would be helpful to many...

Also, SPI now offers a replacement 700 CFI piston that retails at $90 or so.

IQRIDR, Did you or any one else measure the piston to cylinder wall clearence? I am interested in knowing what the tolerance was with the SPI pistons?

If you follow the 4M here you have probably seen the fix it kit from MTNTK that is sold thru PMS Polaris that features the extended length wiseco piston so the cylinder head jugs have to be shimmed to adjust for the extra height but they are just slightly larger in diameter for a tighter cylinder to piston tolerance and this product has changed how the motor sounds and runs.

Thanks for the information in your post about the SPI piston options.

 

[chumbilly1]

?

Why would you not compare weight? Weight compared to oem and also weight comparison between the two pistons, both seem very important to me.
IMHO SPI pistons are not to be trusted in high perf applications. Had a set lose the ring retaining pin at 300 miles in a doo motor with good clearances! unacceptable.

 

[IQRIDR]

Why would you not compare weight? Weight compared to oem and also weight comparison between the two pistons, both seem very important to me.
IMHO SPI pistons are not to be trusted in high perf applications. Had a set lose the ring retaining pin at 300 miles in a doo motor with good clearances! unacceptable.

I simply didn't have a scale handy. And I've probably hand built 150+ motors with SPI pistons and never had the locating pin fail..but that's a problem Doo factory pistons have suffered for 10+ years and also the reason for the 1,000 mile piston recall on all 2011 ETEC motors.

In reply to the previous poster, I have installed the Fix kits and they work great. I'm not trying to sell the SPIs, just trying to tell people about an alternative to spending almost $200 per piston at the dealer if they planned on going the OEM route.

I measured the PTW clearance on a motor I just built with a brand new factory 2010 cylinder, SPI pistons, .006 on both sides. Some people just don't want to do a shim kit and Wiseco pistons no matter how you say it works. That's what this customer wanted, that's what he got. Sled runs great. We'll see how the pistons look in 1000 miles and go from there I guess.

 

[Deucer]

Why would you not compare weight? Weight compared to oem and also weight comparison between the two pistons, both seem very important to me.
IMHO SPI pistons are not to be trusted in high perf applications. Had a set lose the ring retaining pin at 300 miles in a doo motor with good clearances! unacceptable.

Same thing here. Installed two SPI, rode 4 times, pin came out, garbage can the cyl. New cyl and SPI on that side. Less than 500 miles, other side gone. Another new cyl and replaced both pistons with dual ring SPI. One season on them, another pin came out and lost another cyl.

3 out of the 4 SPI pistons tried had the pin come out. 75% failure rate.

D

 

[R44guy]

Same thing here. Installed two SPI, rode 4 times, pin came out, garbage can the cyl. New cyl and SPI on that side. Less than 500 miles, other side gone. Another new cyl and replaced both pistons with dual ring SPI. One season on them, another pin came out and lost another cyl.

3 out of the 4 SPI pistons tried had the pin come out. 75% failure rate.

D

Deucer, thanks for the info on the spi piston and I can say I have heard some questionable outcomes with this product in the past but this takes the cake! So have you now gone to a oem Polaris piston or to another brand?

 

[Deucer]

I should have been more clear. This was on my 05 800 Rev. I now own a Pro Ride 800. Sold the Doo.

Anyhow, I had poor luck with the SPI in the Doo. Polaris may be a different story but if I ever have to rebuild my Pro, it will not be with SPI.

D