08 XP RK-TEK Head Jetting input.

[snosumitcsr]

Interested in hearing everyones input on what jetting everyone is running.
pilot jet, needle shim, or 07 needle. main jet compression ratio, Elevation.

i just installed 13.5:1 3,000-9,000 elevation. put about 80 miles on it, 07 needles are on backorder, no EGT Guage. just looking for what everyone is finding on there setups.

Rod

 

[winter brew]

Down 3 sizes on the mains.

 

[snosumitcsr]

WB, how many miles do you have on the head?

 

[summitboy]

Dootraxx is running a 14:1 from 2000-8000 ft. We put in 450 mains, and shimmed the needle 20 thou. It might be just a little rich in the mid range but is working fine. Runs Shell 91 octane.

 

[madmax]

08' XP 800R. ABout 400 miles on my stock motor with RKT 14.6:1 head, 91 octane pump gas. 7000-10000ft. I'm at 440 mains, took the shim out from under the needle and put it on top (leans the midrange), stock 17.5 pilot jet. I had alittle blubber off the line at first then turned the fuel screw in 1/2 turn and that cleared it up. I also have an airbox mod. Have run this combo at 7500ft in -11degree weather, WOT as long as I dared hold it pinned on a freshly groomed trail. Piston wash still looked alittle rich after the run with a bore scope. These haeds flat rock.

 

[snosumitcsr]

Thanks guys for your detailed info on setup, mine ran fine, but always weary of skidoo's mid range lean. have had RKT heads on past 2 sleds, and they always add performance.

summitboy did you guys add the shim along with the plastic stock shim under needle?

Thanks Rod

 

[summitboy]

Yup stock shim plus a 19 thou. 51 thou in total. Might just go to the stock shim only. Will try and see what it does.

SB

 

[snosumitcsr]

Thanks for clairification.

Rod