Mikuni VM30 - CB350 - Share your specs

[plyzo]

There are a few posts around peoples VM30 setups on CB350 that I figured it would be great to get others to post what worked for them.
Here is what I got working so far on my 1969 Honda CL350:

Location: Central California


Stock Pipes
Velocity Stacks

Slides: 2.5
Needle: 6F4
Needle Jet: 176-P4
Pilot Jet: 22.5
Main Jet: 210
Jet Needle clip:1 from the bottom

 

[Ellwood]

That main is crazy high...you overbore the engine? It's generally known the scott kit is even too rich for most non race bikes and it has a 150 main. I had speedmoto do me two after talking with them on the phone and I have to tell you they were almost dead nuts perfect on arrival. Give them a call and save yourself hours of frustration.

 

[krafty]

71 CB350 w/ CL350 pipes, EMGO shorty mufflers, cone filters that came with the VM30s.

200 Main Jet
#176 P-8 Needle Jet
5F3 Needle at the lowest clip (richest setting)
30 Pilot Jet
.5 Air Jet
2.5 Slide

 

[plyzo]

I did purchase the carbs from speedmoto and their setup wasn't even close to anything where my bike would run good.

 

[Ellwood]

Well...I stand corrected...interesting. I did spend quite a bit of time explaining my bike and the fact I was still rich but running good with the scott kits in mine. Then guess he had a starting point. I swear I have seen so many combos my mind was blown....and that's why I called him. Gonna take you a bunch of plugs...but at least they are cheaper by the dozen. My biggest problem was getting my bike to run well at idle and just off to about 2500 or so where it switches over to the main jet. I was on full lean on the clip.

Hit up the forum over at honda twins...they had a load of vm30 setups


Sea level Myrtle Beach SC

Bike was a 1 overbore with kibble white valves vm30 with uni filters and a 2 into 1 pipe...weak on the low end.

 

[crazypj]

Majority of people running 30mm Mikuni's on CB350 twins are around 145~165 main jet with a 28~35 pilot.
I'll open mine up one day as I can't remember whats in there ;D (not that it would do anyone any good, I made new emulsion tubes to use large roound main jets 8) )
The short exhaust on krafty's bike will neeed more jet but 200 still sounds a bit large

 

[xulf13]

Would it help to mention your current locations altitude etc with the set up you're running?
I am interested to see other peoples set up as well since I am also working on a CB350 motor. But I can't imagine someone in Colorado Springs set up would work on someone's bike in Mississippi, right?

 

[crazypj]

Altitude makes a big difference with slide carbs, CV can somewhat compensate for reduced air pressure

 

[plyzo]

So tonight I actually tried 160 and had no top end it would cut out and only would achieve WOT if I accelerated really slow, but even then would cut out. 210 works way better. I have poor compression readings though. Not sure if that has anything to do with it.


Sent from my iPhone using Tapatalk

 

[crazypj]

Poor compression will make a lot f difference, as will the wrong length exhaust pipes.
You need more jet with a worn engine and a LOT more with a short exhaust as you don't have the 'tuned length' extractor effect and are totally reliant on atmospheric pressure to fill cylinders. 14.7psi pushing through carb has a hell of a job mving fuel, seems we found out why your bike works with massive jets when most won't run with 190