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Need sugestions for pilot/main/needle size for stock carbs


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I have a chance to do some WOT throttle runs and do a plug chop in
two weeks. Right now I have a 2-1 on it with a 35pwk with 60 pilot 170
main and a EEG needle on the leanest clip. (see sig for mods, I'm running the 20cc domes) I rode it for one hour out on
the lake and all it did was spin when it hit the power band. I pulled
the head when my clutch basket blew up and took a pic of the piston
tops. One cylinder looks great but the other one is too rich. I am going
to get the dual carbs setup and try to tune them separately. I looked
through a old post jet form on what everyone runs for pilot's and mains.
I wrote down a bunch and tried to come up with a good starting point.
Pilots range from 25-42. Mains from 290-380 One machine that was similar
in mods and sea level was running a 27.5 pilots and 380 mains. That
seems huge to me. However there wasn't a line for needle size. I believe
that mikuni rates their needle's differently and I'm not familiar with
those yet. I have only worked with Keihin's so far. I would like to know
what is a stock needle size and what would be richer? I'm trying to
gather up a good needle and main selection before I go to tune. I don't
get the opportunity often so I must make good use of the time. I have a
trip planned with the guys in May in upper Wisconsin. They are not going
to stick around and wait for me to tune up my machine. I'd like to have
it ready to rip when I get there.


pistoncolor1hr_zps3b6de1e9.jpg

 

Pic of my rough cut port job.

intakeports.jpg

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Ive got an 04 that I am running near sea level. It has dmc 916s, stock head milled .030, vf3 reeds, +4 timing, open airbox/k&n, stock porting. Its 15-30 degrees here right now and I am running 30 pilots, dynojet 6 position needle onn the 3rd clip, 330 mains.  So 380 mains with your porting doesnt seem all that unreasonable. What is your elevation?

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  • 3 weeks later...

I chopped the threads off the plugs from yesterdays run. They are still grey. I didn't have any 370's so I tried 380's. I will have to get back out to my run when its warmer out and I need to collect some jets that are missing in my mix.

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  • 3 weeks later...

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