Hello!
Bought a 86 this spring and was gonna try to make a bobber out of it.. well surprises came along, and the long story short of a rocky road will come in a different tread later  

The bike now has these mods engine vise :
96mm bigbore, stage 3 cam w/hardned rocker arms, custom downpipe with o2 gauge and dyna muffler. ported head, VM36, k&n replacement for stock airbox, heavy clutch, veryslav`ish tensioner, starterclutch.

VM setup:
PJ 20
(do not remember mix screw, but somewhere around 1.5-2)
Slide cut away 2
Q6 NJ
6FJ6 needle with shim at 1(top)notch
Main 195 (temporary cause of break in)

This combo gives a ok afr reading of about 12.5-13.2 all the way from just past 1/8 and up. nice and even pull. Except just as i open the throttle and the slide lifts, it goes way rich just off idle showing 10.0, and some black smoke from the muffler puffs out. but stabilizes towards 11 ish around a 1/8 throttle, so when cruising, its running a little too rich.

The carb came with a Q5 NJ, and a 2.5 slide, but that was running way lean all the way. lots of backfire and popping, high engine temp.           with needle clip on the 6fj6 in 5 position with 3-4 shims it would run ok in the mid ranges, but lean in the bottom and overall very uneven.

enriching the slide to a 2 and the Q6 has gotten me close to good enoug, except the "10.0-off idle". i found a thread here:
(link in reply post since this is my first post)
which makes me think i need a thicker straight section on my needle.

i`m trying to find the correct needle with the nj/needle spreadsheet:
(second link i reply post)
but i have a hard time figuring what would be the appropriate combo.
since i need slot 5 with several shims on the 6fj6 with the Q5, and the 1 slot with one shim on the Q6, the difference between the graphs is so small i cant figure out what different needle that would be leaner off idle/bigger straight diameter, but perform just as the Q6+1 slot with shim, or slightly leaner.

i`m not very good in maths, nor spreadsheets , and i`ve been reading myself blind on needles so this is where all help is appreciated!


winter is creeping up on us here in Norway, so the only riding i`m gonna be able to do until summer is inside a tunnel with steady +6deg Celsius this winter

and last i wanna thank all the members and contributors on this page for making a online cookbook for mc mechanic, enabling a novice tinker like myself to getting into the fun and joy of a thumper !!!

Thanks
-Martypan

Well, I guess I can say what worked for me....although our bikes a bit different.  I have a 95mm Wiseco, Stage 1 cam, ported head, VM36, big foam sock air cleaner and a custom muffler with baffles.  

I had an O2 sensor on my bike during the tuning process, and I used the #FJ6 needle, Q-5 needle jet, 2.5 Throttle Valve.  Initially it all ran great and I had a slight lean mixture at cruise.  I ended up with a 195 main, #20 Pilot, and the needle clip at the 2nd notch from the bottom (raising the needle).

The bike runs great at all speeds and throttle settings.  If you open the throttle quickly the mixture will go a bit lean - but you have to expect that from a round slide carb.  As the slide raises the vacuum in the carb throat drops - and as a result there is less vacuum to pull fuel out the jets.  That is why some carbs have accelerator pumps (or why they use the CV carb).  You need to jet for steady state running......and don't worry too much about what the carb does while you are moving the throttle open and closed.  When you crank the throttle open you will see the mixture go lean for a few seconds - but when your hand stops moving the throttle the mixture should stabilize within a second or two.

My bike will pop and grumble and backfire if you allow the throttle to close completely while decelerating.....and this is because the slide is dropped and the engine vacuum is high - but the needle is dropped into the needle jet and is blocking fuel flow.  The only fuel the engine can get is from the Pilot Jet circuit....and that is not enough to make a mixture that can burn in the cylinder - so it gets ignited in the hot exhaust header.  If you hold the throttle just slightly open when decelerating you can cut way down on the noise - you don't want to hold it open enough that you are accelerating - just enough that the noise is reduced.

I think you need to expect that the VM36 will run well on the Savage - but you have to put up with some of the primitive nature of the carb.  Suzuki installed a CV carb with the Constant Velocity Slide to help provide for smooth acceleration, and it has a "Throttle Enrichment Valve" to help with the noise during deceleration.  With the VM carb - your wrist has to take the place of the CV slide and TEV valve.  I think my carb is jetted and running about as well as you can expect - this is 1960's technology were are dealing with....not fuel injection.  The only quirk that is worth mentioning, is that if you have to get on the brakes really hard and do a panic stop - most likely the bike is going to stall, as the engine just can't handle going from 4,000 rpm to idle in a split second.