M8 stock head comp

[harf69]

rkt head

im running a 14-1 and when i called kelsey he said that the head is for 5000 and up I run one at 3-6k without issues if you port your cylinders id run a little race below 5k just to be safe

 

[m8magicandmystery]

Yes, I also have a lean spot, about 6-68-6900, and had a bog there too. I added fuel at 6700 mid, and the bog went away. The exhaust temps keep increasing when in this rpm range, no matter what. Adding fuel doesn`t affect it at all. That`s just the way it is..
Also have a bog at 41-4300, and this bog has always been there. Both before/after mods. Add/subtract fuel - no change.
And from idle, when I pin the throttle, it won`t clear up. Like it`s only running on one cylinder. Have to blip the throttle, then pin it..

belt deflection to much...???

 

[harf69]

edit

i need to revamp that statement the 14-1 is the 5000 and up head

 

[jijohans]

The 91 in US is about the same as 98 in Norway. Diffrent ways to mark the gas, MON and RON I think...
http://www.btinternet.com/~madmole/Reference/RONMONPON.html

Jim
Norway

 

[Rms Rydning]

07/m8 is 6.39 to 1


Arctic Cat Engine
Specifications
* F-Series/Crossfire
** M-Series
ITEM 370 cc 500 cc 570 cc 600 cc 800 cc 1000 cc
Engine Model Number AA37A9 AX50L6 AA56A6 AJ60L4 AB80L1 AB10L1
Compression Ratio 6.30:1 6.38:1 6.41:1 6.46:1 6.39:1 6.41:1

That is called commpresson ratio in relations to the exhaust port high.
The stock geometrical compression is 11,8.1.
US 93 PON = EU 98 RON Only diffrent ways of telleing the same..

I would have put the stock head on for testing purpose.If its not getting better check the fuel pressure,sheck if you have leakage around the crank seals (use "startgass").

 

[Runner8]

Altitude

Update;
Rode up to 5000ft last weekend and checked my plugs. Guess what - WHITE!
Added at least 5# on my BD box, and maybe up to 8#. Still white, could hardly see any difference - maybe more grey. However, now it was to fat, so I leaned it out some. Sled ripped and still rips, so I kept it that way and it didn´t burn down

I´m going to put the stock head on during this summer, that´s for sure...

Rydning: fuel pressure is at 45,5-46 - so it´s ok.

 

[Camo-toe]

Anyone have a stock 800 head they would like to part with??