? About 07 Summt 800R Comp. & Heads

[MGD]

Wondering why the low stock comp. on Summit 800R's. Will going to 13.0 make much diff. How safe is bumping it up to 13.5. Mostly Riding 4000' to 7000'. Thanks for any input. Also is the stock comp. on a 05 Summit 800HO 13.5 ?

 

[Concrete Mike]

I think the comp # 's are low because of the port timeing.My cuddney head is
13.5 i think and it added just under 2o psi.it is now the same as my 02 800 140 ish.
The head really waked up my machine.Mike

 

[Silent Bob]

I started with 123 psi, shaved head 0.010" and gained 4 psi. Got a new engine and it was 125 psi, added the RkTek 14.1 head and gained 10 psi. Then added Sled Head Racing dual ring pistons and now it is close to 150 psi.

Totally different machine and easier to clutch.

 

[Reeb]

13.5 on all the ones I've sold locally. SLP, Engine-Tech, Terra Alps, etc etc. Really wakes them up and gives them the compression they want.

 

[MGD]

Thanks for the replies, don't get on here much. Any one out there have a 13.5 head for the 800R, preferable engine tech ?