Identifying carbs? (Pilot screw adjustment, please!)

On my 650B3 project the set of carbs do not match what I and the factory service manual expect for a 1979 model. They look like they might have been NOS at one point as they like quite new in certain areas.

They are the Mikunis with the air screw below the throat and on the engine side of the bowl and do not have the accelerator pump. I assumed they were VM22SS as my factory manual lists those models being used on the 1978 bikes. A discussion with Tazzman has me wondering just what they are.

On the mounting flange there is a pair of numbers stamped in each carb, 102 6. Does this match the Kawasaki part number of 16001-1026 that is shown as the part number of the carb set for the KZ650B2A? So far I've not needed anything except the airscrew O-rings as I've gone through them so this isn't a parts issue, yet.

- Nate >>

Post edited by: N0NB, at: 2006/05/02 17:05

Here are pics of the carbs in question:







- Nate >>

Sorry Nate but I have never found good Mikuni VM series carb ID pics. I'll dig around because I have always wanted positive ID for my set also. I really have no way of telling if I have the original set on this bike, even though I suspect that it is. B.T.W. four "O" rings were sent yesterday. I'll see what I can find for carb identification.

www.sudco.com/mikuni2.html#VM

The carbs in your pics are EXACTLY like mine. And I do mean exactly. When You pos. ID them, please let me know. I'm going by my original Clymers info that my 77 B1 has Mikuni VM 24SS carbs.

Post edited by: gas, at: 2006/04/28 12:13

That begs the question, was there such a thing as a VM22SS or is that simply a typo in my factory service manual? I do know that the jet size in these is way different (90?) than those in my SR (97.5).

- Nate >>

The jolly old elf from Texas would probably know, but this is likely a busy period for him.

A page from my Factory Service Manual. Note the VM22SS specs at the top. I'm wondering if the specs may have been meant for another model bike. There is no other mention of 22s anywhere in the manual.

.


Post edited by: rstnick, at: 2006/04/28 21:56

Thanks, Rob.

Based on the fact that my main jets are 90s, there are two pilot jets, 1 and 2, and the other similarities that exist, I conclude that I have a set of VM22SS on this bike. My factory service manual has a part number of 99924-1007-03 and covers the B2A to B4, C3-C4, D1A to D3, E1, and F1.

My service manual lists the VM22SS specs (and labels them as such) on page 151 and match those yours shows and the my B's carbs exactly. In the 1979 appendix, it lists the VM24SS specs which match the carbs on my SR exactly.

- Nate >>

Damn ! Looks like mine are 22's also! I DO have the small normal pilot that drops/screws in below that fat 50 sitting above it. What threw me was that when I first opened mine, I found the standard 15 pilots, but 97.5 mains, not the 90's listed. Of course the P.O may have changed them. Oh well, as long as I can get it running to my satisfaction it's all good. However, this does make me wonder if I have been having a challenge with these things because I ordered rebuild kits for 24's, thus different needles. Hmmmmm. Ah, to hell with it. If it runs alright, I don't care what I have.

I am not sure if there is such a thing as a VM22... I think those are 24s. Measure them! The earliest 650s came with the air screws on the sides and the later 70s came with the pilot fuel mixture screws as shown. Keeping the needle jet and jet needle fairly matched is important but not a big problem on the non accelerator pump VM24s but once you get to the pumpers, the needle jets shrink down some and the wrong jet needles can cause performance issues.

What jet needles are in those things? 5DL31? 5CL10? I have some info on ID marks for the 24s but it isn't very organized and I really need to get it into a spread sheet. I intend on eventually putting together an ID guide on my web site but as noted, this is busy season and I only came out of the shop this fine Saturday AM to do some internet research on GPz750 carbs so had best get back up and finish them!

Yes, the original needles in mine were 5DL31.

N0NB wrote:

Thanks, Rob.

Based on the fact that my main jets are 90s, there are two pilot jets, 1 and 2, and the other similarities that exist, I conclude that I have a set of VM22SS on this bike. My factory service manual has a part number of 99924-1007-03 and covers the B2A to B4, C3-C4, D1A to D3, E1, and F1.

My service manual lists the VM22SS specs (and labels them as such) on page 151 and match those yours shows and the my B's carbs exactly. In the 1979 appendix, it lists the VM24SS specs which match the carbs on my SR exactly.

- Nate >>

We may well have the same manual. Mine covers 78,79,80 starting with the B2A and ending with the F1. I did actually find 650's listed as having Mikuni VM22SS carbs. The pages open in front of me right now (specifications page 6)list the B2A and DIA with the 22's. I also found the spec list that Rob previously d/led for the 22's. Unfortunately my F.S.M. does not cover the 77 B1 and I was going by the info in my Clymers manual also, which seems to conflict, as it lists my B1 with 24's. I suppose WG is correct about measuring them, but that will have to wait until they come off again and I don't see that as any time soon. If anyone has a Factory Service Manual that covers the 1977 KZ 650 B1, please tell me what it lists for carbs. Thanks.

gas wrote:

If anyone has a Factory Service Manual that covers the 1977 KZ 650 B1, please tell me what it lists for carbs. Thanks.

Chris: My KHI manual lists VM24SS for the KZ650B1 model...making the Clymer correct:lol: