piston clearance on rktec 860 ?

[2revbigbore]

what clearances are you gents running in 800r/ rktek 860 motors?

what clearance is the min. for a stock piston/stock skidoo 2007 800r
in your experiences?
thanks

 

[2revbigbore]

somebody has to have an opinion on this?

 

[wepons]

Interesting story

It is interesting you bring this up. When I bought a XP my buddy decided he would keep up with the Jones by buy the 860 BB kit from dealer, so he wait the manditory 2 month waiting period, got his parts, call the owner of the company for advise, and "tolerance" questions. Soooo he put his motor together, did the proper break in. He made it about 4 miles, before I pulled him home on a rope.

So he called the manufacturer, and talked to "the Man" and he was promptly given a different tolerance..... Interesting........ So he put it back together after sending his heads out to get redone, and we took it out and it did the same exact thing. So now we have the sled in the garage and a certain company, wont return our calls.... Go figure....

So to answer your question, with a question.... Who do you ask if the manufacturer will give you different info each time you talk to them

 

[Summit Guy]

6 thousands is what my original 827 was, that is a little tight 7 thousands seems to prevent the four corner seize if not warmed up properly.

The race manual say 5 min and 8 max in thousands

 

[summit800]

so was that piston clearance or ring end gap???

 

[wepons]

Pollack

So how long do you have to be in Poland to me an official Pollack???

 

[summit800]

45 days plus or minus 5 days

 

[Summit Guy]

6 thousands is what my original 827 was, that is a little tight 7 thousands seems to prevent the four corner seize if not warmed up properly.

The race manual say 5 min and 8 max in thousands

This cylinder wall clearance

ring end clearance is .016 - ..022

 

[hymark860]

I run .006 with wisecos on a Turboal Al 860 HO. Water temps run from 75 to 95 degrees hill climbing all day long. .018 ring gap.

I have a R motor too but its not done. I believe its the same clearance.

 

[JROD]

Be careful running nitrous if running that kind of ring end gap. Could be costly.

What are these heads running for squish and squish band width?

 

[fredw]

6tho clearence on the 885cc with single ring 86mm weiscos and running strong, just turned 700 miles on the little girl... 460 mains

 

[hymark860]

Be careful running nitrous if running that kind of ring end gap. Could be costly.

Why, what would be the problem?

 

[Ox]

Sounds like some folks just kant help themselves to rippin' on a cold motor?

I have ran .004 since '02. I would have felt a little warmer and fuzzier with .005, but I never had a cold sieze. My stock pistons were .008 and were WAY too sloppy and had terrible premature wear at 2350 klicks. (1500 miles prox)

 

[masneri]

I was thinking about getting an rktek 827 kit for my 06 800 ptek. Are these kits really finnicky? do you have to mess with it everytime you go up in elevation or can i just put gas and oil in my sled and go? I want the extra power but i dont like "tweaking" on my sled everytime i go ride.

 

[BIG JOHN]

clearances

.005"-.006" stock
.006"-.007" stock bore wiseco
.006"-.0065" 860R cast piston
.007" 840HO wiseco
.006-.0065" 840HO German piston

add .001" for NOS applications-BJ