Top end kit how often?

[scottm]

How often do you replace the top end on an M-series sled?

I've got a 2006 M7 with 2700 miles of deep snow boondocking. Sled spends much of its life pinned to haul my 225 lbs around, and is mostly stock with aftermarket intake and can. With my dirt bikes, the 250 2T got a new top end every 50 hours, the 450 4Ts every 100 hours. Haven't done a compression test but have a tester.

 

[TheBreeze]

rebuild

2700 miles is nothin' as long as compression is good.

 

[Stack]

I agree....As long as the compression is good keep riding! Many 700 laydown motors with 5000 miles on the top end....no issues

 

[ripsass]

When ever the compression starts to drop. I usually do mine when when it drops 8-10 PSI or there is a 5 PSI or more difference between the cylinders.

 

[89sandman]

i've got just over 5,000 hard miles on my 07 M8 and i just did pistons. they looked perfect still could have easily just put in rings but figured while i have i apart whats a couple of extra hundred bucks...

 

[Bill1010630]

I know of an 07 M8 owned by a tour company in the Rockies and it has 9500 miles on it.The engine has never been apart and the compression is still in spec,pretty incredible in my mind.

 

[05snopro440]

2700 miles is nothing on an M7, check the compression at the beginning of every season and don't worry about it.

 

[CATSLEDMAN1]

I agree

I'm about to tear down my 07m8 with over 5000 miles, was going to order pistons, decided to wait and see. I'm been researching if 2010 piston are better, would add hp or ? Dark subject so far, no answers.


And by the way.............any one doubting what good or bad pistons and rings can do check the latest DYNO TECH post/test/evaluation /tune on test of a single ring Polaris 800 with stock not so good pistons and then updated pistons. WOW.

 

[1MEX]

Anyone know the compressin should be on stock '05 M7 at 4500'?

 

[knoba]

M7

My M7 at 6500ft was 120 so you should be 125 to 130 ish.

 

[ripsass]

I would not try running the 2010 pistons in an earlier 800. They are balanced to the lighter 2010 crank shaft.
If combined with an 09 or earlier crank there will be some serious weight compatibility issues.

 

[scottm]

Awesome, thanks everybody. Will do a compression test when I throw on my new Power Claw track and Holz relocation brackets, and service the diamond drive.