Jetting

[BillyG]

What are you guys using on 38's non powerjetted, no air box, for everyday use?? I'm going to finish up #55 for the guy that bought it from me. I remember the needles and nozzles I had in mine, but they were powerjetted.

[Trucker]

I had 340's in mine with just velocity stacks

[BillyG]

340's with QO's and 6DH4's or 7's, I had 7's in mine and staggered nozzles

[Trucker]

i had 6 dh7

[thomy]

Just to confirm for future searchers on this topic:

Temperature approx 15 degrees and clear sky

38 MM VM with no airbox and no velocity stacks
350 main jet
6DH7 clip in forth position from top
247 Q-0 needle jet
17.5 pilot jet (reduced because of the next item)
U.F.O.s -when I put these on I instantly lost my low end bog.

Edit:
mixture screw 1 3/4 turns out
porting: took 1mm off top and sides of exhaust ports, fitted outlets to Aaen Pipes, and polished them.

Now I wonder what it'll do with 40mm carbs.

Thom

[Tory944]

...  just for the record, this is exactly the same calibration I was running on the stock Interceptor @ the 1000ft radar runs.  The clip position is the same also...  this was before I read your post!  Interesting.  I will confirm that this was a good set up.  Thanks for sharing.  You guys might wanna write this down in your notebook.

[discus]

Are both you guys running UFO's? How do you like them?

[Tory944]

  They work well as long as your baseline (calibrations) are close.  DO NOT do any grinding on the throttle slide - start out with a 3.5 cut out to begin with.  The directions tell you that you can "grind" a 2.5 to match the UFO.  DON"T DO IT!  Very small changes to the slide cut out will throw everything off if both do not match.

[thomy]

I had a bog that was hard to shake. When I found a couple of Polaris carbs in my stash with UFOs on the slides I put those slides in the carbs on the Interceptor. You have to dramatically reduce the pilot jet to use the UFO due to the greater suction in the venturi. I heard a dramatic difference as soon as I started the engine and the bog was gone. It pulls hard all the way through the RPM range, which with my setup is 9500 RPM.