VM33 jetting?

All those charts were for the 33s? Some of the data was quite strange hehe

The small mains are most likely Dynajet mains and may or may not be the same as Mikunis. Get a set of Mikuni mains (about #140) and do a plug chop. See what pilot jets are in there hehe Thanks for doing the typing.

Those charts are from Mikuni. A direct quote from The G.S.Performance literature that came with my carbs..My pilot is 22.5 Needle jet 0-8.I checked my plug after riding home at 3500 to 4000rpm About 1/8 throttle and it is black.
Post edited by: mark1122, at: 2006/09/01 09:21

Post edited by: mark1122, at: 2006/09/01 09:23

I got this off the KZ900.com web site."In order to get better throttle response with 33mm smoothbores install 0.6 air correction jets.This alows you to run a smaller main jet while still giving you aproximately the same air fuel ratio.A good starting point is 4 main jet sizes smaller.Also instaling a 0-6 needle jet will help lean out the mid range." I have a 1.2 air jet.What do you think of this ?.Should I try it?

I tried a few dif mains today.138.5,140.142.5,145.The 140 looks good .Light tan color.I tried a 15 and 17.5 pilot jet and it looks like i can still go lower so I will try to get a 112 tomorrow.

the 3rd. hole from the left of each carb has been filled with some sort of filler ,epoxy maybe.What purpose would this serve? They were oridginaly used on a race bike.:blink:

All those holes on the intake edge of the smoothbores were put there to make them look fancy. Only three serve a purpose. On the 33, the choke air intake is one, the air intake for the main jet system is one and the pilot jet system is one... just like every other VM series carb. The reason for the choke air inlet is to supply air when the slide is closed. The same with the main and pilot circuits. One of the two is pressed in brass and the other is a small screw-in jet. I can't recall which goes to which but if you are curious, get a can of carb cleaner. Open the slide and spray into each of the holes. On the dummy holes, you will get it back in your face so watch out. On the MAIN JET air jet, you will see carb cleaner dribble out the main jet. On the PILOT jet air jet, you will get it spraying up through the small hole behind the needle jet in the bottom of the venturi. This is also a good way to ensure that these passageways are clear. If you the pilot jet test with no jets in, put your finger over the air screw hole (on the side) and the pilot jet well. Carb cleaner should squirt through in a nice mist.

Thanks. What do you think about reducing my air jet size?