compression ?? on 05 rev

[t stone]

I checked the compression on my 05 rev. It has 3000 miles on stock pistons. The sled still runs strong. The compression is 112 lbs on both cylinders. What is the ideal compression? does it need a fresh top end? please imput.

 

[907to406]

I would say its time for a new top end. What elevation are you at and are you holding the throttle wide open while you pull it? Also I'd try to check with at least 2 different compression testers as they can vary radically. My 05 rev has a high comp head with about 700mi on the new motor and my compression was 155 and 149 at 4600ft. Not sure what the comp should be on a stock head though? Also I would suggest doing a top end every 1500-2000 miles.

 

[Tackbtch]

04, stock except for double ring pistons. 500 miles on rebuild. 2200 feet , throttle wide open,... 155 # both sides, cold. Sled had 135 pto and 128 mag side with 3800 miles, I would say to rebuild the top and at least check the crank bearings Dino

 

[eddy]

Compression

2005 800HO at 400 feet elevation 155 lbs all stock 1750 miles when we checked last summer

 

[t stone]

I would say its time for a new top end. What elevation are you at and are you holding the throttle wide open while you pull it? Also I'd try to check with at least 2 different compression testers as they can vary radically. My 05 rev has a high comp head with about 700mi on the new motor and my compression was 155 and 149 at 4600ft. Not sure what the comp should be on a stock head though? Also I would suggest doing a top end every 1500-2000 miles.

Im at about 3800 ft. I did hold the throttle wide open and checked it twice on each cylinder. Sounds like a new top end. Thanks guys for your imput.

 

[bikerjustin]

Regardless of what the compression is... With that kind of mileage, replace your top end before you tear up a cylinder and it gets expensive.
Hindsight is 20/20. I sure wish I replaced mine last summer. The good news is my parts showed up today. MCB 2 ring pistons- and a new cylinder, and a new exhaust valve. I think I got off pretty easy too.