Mikuni VM 33 Carbs

Hi Steve,

I was wondering where you ended up on the tuning (jetting) on your VM33's?

I ask because I am planning on running the same carbs with a air box and noticed you also using one (not very many examples of them with the air box)

Could you list your setup if you don't mind? (engine CC, head work, exhaust etc.)

1075 was 1015 both Wiseco pistons, mild porting, (Big difference), Andrews 1X cams, V/H exhaust, Dyna S, green coils and K&N air filter. 
130 mains, 1.2 air jets, added an extra hole in the emulsion tubes going to 27.5 pilots with the Taylor wires. Too lean before with #25's too rich with #30's. 1.5 slide cutaway. Needles in the center position. 
Was fine with with resister wires at #20 pilots. 
Pulls great in all gears and no bog at WOT in 5th. 
Steve

Bought my carbs like this :



After some clean up and parts replacement there are ready to bolt on :






Pre jetted for 1197cc 10.5:1 motor, big valve head, 420 lift Web Cams shim under, 90CFM port job, running a CV air box, stuffed in a stock looking KZ650 C3 build.
 

Here’s mine. Rebuilt stashed on the shelf.

 

They look GREAT gentlemen. Mine were in rough shape. With the help of a couple members they are tunable and work as good as they should. The complaints were "Bogging at WOT". Mine don't do that. Good throttle response throughout the RPM range. Roll on is flawless. Just not as pretty as yours. 
I'm just RIDING THE PISS OUT OF THEM. 
Steve

Mine were rebuilt cheap and nasty... Pine Sol soak and elbow grease

I did replace some rubber parts and fix one float (solder job)
Over all they were not that bad, some jets were seized but I got a torch out and they broke loose.
They just had some normal corrosion on them from years of use.
I did have to fix some PO installed sync ports that were drilled to the wrong size for adapters, redid them at M6 then installed button head Allen bolts with O rings.

I chose VM's over RS flat slides because Larry C had them on his 1200 and he liked them a lot, plus they look more stock than a set of flat slides. I am going for a mostly stock looking build except its a 650 with a 1000 motor in it.

 

My Smooth Bores have been sitting on the shelf for quite a while but they are going on the bike this Spring. I must have changed the main and pilot jets 3 times already but have settled on first start jet sizes.

My engine build : 1197cc MTC 10.5:1, 37/31 valves stage 1 ported Z1 head (96CFM int/73CFM ex) RC .425" cams, Custom 4 into 2 exhaust with stock 650/750CV air box

Jetting :
slide cutaway = 1.5
jet needle = #6DJ30
needle clip = #3
needle jet = #O-6
main air jet = #1.2
pilot jet = #25 (TBD ColorTune)
float level = 22.5 mm
pilot air screw 1 turn out? (TBD ColorTune)
main jet = #125 (1&4) #127.5 (2&3)

The exhaust and air box are going to choke it off a bit but the final jetting will be confirmed by a on bike AFR gauge.
 

Be interested if there's an overheating issue with the 1197 setup. 
Steve

SWest wrote:

Be interested if there's an overheating issue with the 1197 setup. 

Steve

 

I am going to be running a big oil cooler as the liners are on the thin side. I also have differential mains, one size richer on the center cylinders so that should help with the heat.

The pilot and main selection is a unknown but the AFR gauge should help me pinpoint correct jetting much quicker than in the past.