Evo 80 inch jetting question

[gsxrboy96]

Ok, so im a die hard keihin guy..but my buddy has a bike that has a mikuni on it, which ive personally never had a bunch of experience, soooo with that being said, I need to jet the bike,its a .010 over 10 to 1 80 inch with a andrews ev46 camshaft and screaming eagle heads, Can someone give me a baseline for a hsr42?? would be greatly appreciated. thanks chad.

[rcsoftail]

Factory settings are very close, just change the main jet to a 165 and put in a 60 accelerator pump jet.

End result should be something like this.
25 pilot
165 main
Leave the needle clip in the middle
Air screw out 2 turns
I think the 70 accelerator pump jet is to rich and would use a 60 instead.
Make sure there is about a 1/16" clearance between the acceleator pump rod and the white plastic peice at idle. If it is touching, the accelerator pump be squirting some fuel at idle due to the engine vibration.

The mikuni tuning guide is very good and will help you fine tune it. It can be downloaded from their website.

[TheNowhereman]

Your engine mods are quite mild.
Your low speed jetting will tell you where to go.
If you have to go over 2 turns out your too rich.
Like wise if you have to go under 1.5 turns your probably too lean.
If your on, it should be 1.5 turns out.
That will take care of your 1/4 throttle setting.
I prefer to jet my Mikunis the hard way.
If Im lean in the 1/4 to 3/4 throttle range, I richen up that area with a new needle jet.
I keep my needles in the middle clip positions if I can.
Moving the needle clip just advances or retards the specific amount of fuel the needle jet can deliver.
Either more or less comes in at a specific throttle setting.
The total amount to be delivered does not change though.
You can also by different needles to fine tune the amount an delivery point.
The main comes in at 3/4 throttle which you almost never ride at but, if you get to a drag strip or a long safe piece of road, you can work that out.