Jetting Help--KZ1000-M2

I posted the same question in another thread, but it was buried among other questions, so it never got answered. So I'll try again with a thread for this specific question.

I have a KZ1000-M2. The PO said that it had been bored out to 1100cc's, and had new valves put in. I don't know what kind of piston kit they used, but looking through the plug holes, they look like standard KZ pistons (maybe from a KZ1100?).

When I got it, it had a set of VM28 carbs on it. It ran...barely. But the carbs he put on had not been tuned to this bike at all, and they were DIRTY.

I decided to go back to the original carbs that came with the M2, so I picked up a set of BS34s on Ebay. They were advertised as having come off of an '83 KZ1100 Spectre. So I figured, since they came off an 1100, and my bike supposedly has 1100 pistons, maybe the jetting would already be close.

So I got the carbs today. They had obviously been sitting for a long time with gas in them. They are filthy dirty. But seem to otherwise be in servicable shape.

I pulled the jets, and they have 120 mains and 40 pilots. My question is this. Does this sound like a good starting point with these jets? Or should I change the jets to a different size? I have a stock airbox and non-stock 4-2 turnout pipes.

Thanks.

According to the manual, the stock jets for the BS34's on a KZ1000J are 127.5R mains and 37.5 pilots. That would probably be a good starting point, but keep in mind I am no carb expert

1981/2 KZ1100D
Main Jet #120
Pilot Jet #40
Jet Needle 4CG14 (non US 4CG15-3)
Needle Jet Y-1
1 ¼ turns out mix screw
Fuel Level=3mm
Float Level=19mm for all assemblies

I think those carbs will work well for you without need of any rejetting given you continue to use a stock airbox and just run the pipes...

UPDATE

We'll I mounted the carbs with the stock 1100 jetting a couple weeks ago, and it fired right up. But as I was still waiting for new airbox boots to arrive, and the old ones were rock-hard, so I was testing it with no airbox connected--I just covered the intakes with a rag to provide some resistance and filtering long enough to test it.

It seemed to run okay, but just in the garage. Didn't take it out on the road.

Anyhow, it continues to burn a lot of oil--lots of smoke out the exhaust. So I decided to pull the head and have a look. There was indeed oil leaking from the corner o-rings, past the head gasket, and into the 1 & 4 cyls. So new gaskets and o-rings are on order from Z1E. I also checked the head surface, and it is flat, not warped.

So, while I'm in there, I measured the bore. As I wrote upthread, when I bought the bike, the PO told me that the guy he got it from said they had bored it out to 1100ccs. Well, that was BS. The bore is still the standard 69.5mm. Frankly, I don't really care that much.

But it does bring back up the question of jetting. Before, I had asked for a jetting recommendation based on the assumption that I had 1100 bore & pistions. WG provided the stock jetting specs for the KZ1100 which matched the jetting I have on the BS34s I bought (120/40). Now that I know that I have stock 998 bore, would you recommend any changes to the jetting? As a reminder, I have stock airbox and aftermarket 4-2 turnout pipes.

Thanks.

steell wrote:

According to the manual, the stock jets for the BS34's on a KZ1000J are 127.5R mains and 37.5 pilots. That would probably be a good starting point, but keep in mind I am no carb expert

Maybe I should have re-read this thread before posting the last post. :whistle:

So according to this info, I should go up 3 sizes on the mains and down a size on the pilots? Anyone else have a comment on this?

Thanks again.