Will these carbs work?

My newest project acquisition (KZ1000-M2)came with non-stock carbs which the PO pulled off another bike.

From what I understand, stock carbs for my bike are BS34s. I think what I have are VM28s with accelerator pumps. The output ID measures slightly over 28mm. The number stamped on the #1 carb flange is 1098. Current jetting is 105/15.

The PO told me that it recently had the top end redone, and bored out to 1100 CCs. It has a non-stock 4-2 turnout exhaust. Stock airbox.

When I first looked at the bike, we were able to get it running, but it coughed and sputtered quite a lot, and puffed black smoke. But the guy didn't have the airbox mounted. The carb intakes were open to the outside.

So my question is this. I am probably going to try to find some stock BS34s for the bike, but would like to first try to get it running well with the carbs I have. Is there any reason why I shouldn't use these carbs? What would you recommend for jetting?

There are a couple problems with using the VM28s. First, these carbs bump against the petcock, so I'll have to figure something out with that. Plus, I should change to a 2-cable throttle control if I plan to ride it. Like I said, I'll eventually try to get some BS34s, but want to try the 28s as a temporary solution.

The carbs you have on it should be able to be made to work well. You might try to pick up a set of throttle cables off an 81 650 CSR, they should be about the correct length assuming you still have the stock mini-apes on the bike. The petcock problem can be solved by getting one of the Suzuki style replacement petcocks from Jeff at Z-1. As to the jetting I think that is a WG question but my gut reaction is that they sound like they might be a bit too lean. If you do decide to go with the stock BS34's you might try picking up a set from a cop bike there is a place (western escort IIRC) that sells all kinds of parts for cop bikes you might check with them.

Thanks, Gringo.

Yeah, I also thought about using the Suzuki petcock, especially since I already have one on my B2. I replaced the leaky original with the Suzuki one a few months ago. I can now take the petcock off my M2 and switch with with the Suzuki one on my B2. Now my B2 will have the OEM one again.

Thanks also for the advice about using the 650 CSR throttle assembly. In looking up the part number, it looks like that exact same assembly was used on 550s and 750s too. So I should be able to find one.

Now I just need to figure out the proper jetting on my VM28s. Hopefully someone here (WG?) can opine on that subject.

Edited to add: I just saw the thread about WG being gone for a while. I hope all is okay with him.

Post edited by: Skyman, at: 2007/08/17 23:30

You shouldn't need to change anything other than the cables. Check your RH switch casing and I'd be willing to bet it is already tapped for the closing cable, it probably has a plastic plug in there that you can just pry out. The 750 LTD cables won't do you any good because they came with CV carbs and only used one cable with the same setup, the closing cable threads blocked off with a plastic plug.

Gringo, my bike appears to use a completely different RH switch casing than what you are thinking. There is no hole (plugged or otherwise) for a second cable. The single thottle cable exits the casing from the front, not the bottom. There is definitely only accomodation for a single throttle cable.

And on the throttle drum, there is only one slot for the cable nub.

I just found a set of carbs on ebay that look like BS34s. Descriptions says they are from a Suzuki GS1000. Any reason why these wouldn't work?

The Suzuki's use a different setup for the choke it is actuated with a cable instead of a knob on the Kawis. They could be made to work but it will take some dicking around to make them work. You would be better off getting a set from a Kaw they shouldn't be too hard to find. I just picked up a like new set at Mid-Ohio for $20.00:) that I plan on using on a 750 GPZ engine I have.

The Gringo wrote:

The Suzuki's use a different setup for the choke it is actuated with a cable instead of a knob on the Kawis. They could be made to work but it will take some dicking around to make them work. You would be better off getting a set from a Kaw they shouldn't be too hard to find. I just picked up a like new set at Mid-Ohio for $20.00:) that I plan on using on a 750 GPZ engine I have.

What is "Mid-Ohio"? Is it a store? A swap meet? Or just the geographical location where you found it? :lol:

Man, if I could find a set anywhere close to $20, I'd be very happy. I've seen a few on Ebay recently go from $130-$250. :pinch:

Well, I just picked up a set of BS34 carbs on EBay from an '82 KZ1100 Spectre. I figure that if my bike does have 1100 pistons, as the PO said, perhaps the jetting on these carbs will be close. We'll see when they get here.

From the photos, looks like someone painted the carbs black.

Will carb dip (like that NAPA stuff) take paint off?

Post edited by: Skyman, at: 2007/08/20 11:53

Sorry Mid-Ohio is Mid-Ohio Vintage days that just happened at the end of July. Biggest vintage swap meet in the country with 1000 plus vendors.

As to the carbs you just bought, the Spectre models came painted black from the factory. The seller is probably right the jetting should be real close for what you have. I don't know that I'd screw with trying to remove the factory paint from them, as I understand it it is a real beach to get it off. Unless you are trying to do a 100 point restoration I'd leave them as is JMHO.

Thanks Gringo.

I wondered about it being factory paint. Seems that every set of carbs I've seen from the Spectre is black. I guess I don't mind having black carbs if the paint is in good shape. We'll see what they look like when they arrive.

Still waiting for the BS34s to arrive. But can anyone offer advice on what the initial jetting should be, given my bike configuration?

Thanks.