600 Cleanfire top end rebuild information?

[SaskRMK]

Well after a hard season of about 1000 Miles 75% which have probably been full throttle my 600 RMK needs a refresh. After a cold compression test i got a reading of 90-109 compared to 120-125 at the start of the season. The sled still pulls as hard as a stock 600 should(can+reeds) but i would rather rebuild now then after a melt down.

If my cylinders are still in good shape i was planning on getting them diamond honed as well as the tolerances checked and then replacing my pistons with the high end SPX ones. What is acceptable when it comes to a cylinder honing? what is the acceptable internal diameter of a honed cylinder?

What do you suggest when it comes to pistons? SPX? SPI? Wiseco? OEM?
I am able to get 2 of the high end SPX pistons+ Winderosa top end gasket kit for under $300 right now in stock.

Really what i am looking for is any thing i should take into consideration when rebuilding my top end.

Thanks in advance guys!

 

[diamonddave]

I would call Chris Kasel at Carls Cycle. I like the OE pistons but also really like the Art ProX pistons. Not sure if they are available for the 600 CFI. Or if you want a sleeper, install a 660 kit from Carls and smoke 800's.

 

[Boston Racing]

Carls 660's dont smoke 800's anywhere we ride (6-13000 feet) I have Weiscos in my 660 (HO not CFI) and they are still at 125 cranking with 3000 miles on them. I didnt even freshen it up when I installed the turbo. IMO weiscos are the best pistons out there....if you let the sled warm up properly.

 

[SaskRMK]

I also let my sled warm up before moving it. Would you suggest the wiseco pistons on more of a lightly modified machine?

 

[NapaMatt]

My .02

I would use stock pistons..

alos X2 on the warm up..

i have 3 seasons on my 600 still at 125 psi compression!!!

 

[diamonddave]

Carls 660's dont smoke 800's anywhere we ride (6-13000 feet) I have Weiscos in my 660 (HO not CFI) and they are still at 125 cranking with 3000 miles on them. I didnt even freshen it up when I installed the turbo. IMO weiscos are the best pistons out there....if you let the sled warm up properly.

I've heard you say this in the past. Something must be going on. We ride 2,000-6,500 ft. I have a couple 660 CFI's and set up 3 685's carbs (which are faster btw) and they will all take the 8's in all conditions until the deep hits 4 feet plus. Then the torque of the 8 will just get by the 660's. 685's are equal in the 4 feet. My set-up's on the carb'd are quite a bit different than Carls. The 660's use a stock 700 piston.

 

[SaskRMK]

I don't think the wiseco pistons would suite my riding style. I do a lot of starting and stopping. The weather in my province is also very cold and this could cause an issue with optimal operating temperatures as well proper warm up time.

Polaris wants almost $200 a pistons not including pins,ring and clips so i would probably be at almost $500 including everything.

I can get both high end SPX pistons all pins, rings and clips for under $175
In stock

 

[SaskRMK]

I don't think the wiseco pistons would suite my riding style. I do a lot of starting and stopping. The weather in my province is also very cold and this could cause an issue with optimal operating temperatures as well proper warm up time.

Polaris wants almost $200 a pistons not including pins,ring and clips so i would probably be at almost $500 including everything.

I can get both SPX Quantum pistons all pins, rings and clips for under $175
In stock

Apparently these are the exact same as the SPI Hyperdryve and are made by Namura as well.

Has anyone used these pistons?

 

[SaskRMK]

Well i pulled the top end apart today and the exhaust side that had 90 PSI was in bad shape. I am very lucky i was able to catch this before it locked up on me. Any clue what could cause this sort of damage? I did have that issue where my oil line had run completely dry from the check valve to the pump and maybe this happened before i caught on?

beside the new SPX Quantum