Topic: 836 - what's a good starting place for the jet size?

[sangyo soichiro]

I'd like to have a starting place for the jet size and go from there. 

Here's my setup:

First the things that have changed:
- Wiseco 10.5:1 CR 836cc
- "Mildly ported" head - hemi'd combustion chambers, polished exhaust ports, I opened up the intakes; basically I tried to emulate this article:   http://cb750k2.tripod.com/Technical/porting/Porting_the_Honda_Head.htm
- Stock valves, but polished up real nice 
- Webcam 41a grind hardweld cam (0.360 lift, 280 degree duration)
- APE lightened crank

Stuff that hasn't changed:
- Stock carburetor, currently at 120 mains
- Mac 4-1 exhaust
- Either pods or stock airbox (I have both, and currently using the pods)


Before the changes it ran well with the 120 mains.


So what might be a good jet size to start out with for the fine tuning?  Something that might get me pretty close to the final size.

Thanks in advance.

[Jerry Rxman Griffin aka MuthaF'er]

Maybe try 120's with pods and plan on going up or 120's and going down with airbox.

[wrenchmuch]

I'm running 125's , needle in the middle , 35 idle jets with about 3/4 turn out on the air screw . My set up is almost the same except I didn't hemi the head (mild port job )
And I'm use a #41 grind with stock air box . Plug colour looks good at these settings .

[Old Scrambler]

I started with the 35-120 combo with pods and nearly the same setup on my brother-in-law's bike. It ran poorly at constant speed. I went down to 117.5 mains and it runs much better but still not perfect after about 1,000 miles. Be sure to consider the altitude.

[mlinder]

If you are using stock airbox and filter, the only thing you have to rejet for is the exhaust. Slight bump in CC size shouldn't affect jetting. If they can feed a 736 at 11k (which they can), they can feed an 836 below 10k.

[sangyo soichiro]

Thanks a lot guys.  I was worried that with all the changes I would be completely out of whack with the jet size.  But it appears the ones I have turn out to be a good starting place.