KZ1000 JETTING

We had a customer bring a KZ1000 shaft drive bike in with Mikuni VM29 carbs on it, this bike has a Vance & Hines 4-into-1 competition header on it with no baffle & K&N pod style air filters. Any one have any idea where should we start with the main & pilot jetting?

Fastrax wrote:

We had a customer bring a KZ1000 shaft drive bike in with Mikuni VM29 carbs on it, this bike has a Vance & Hines 4-into-1 competition header on it with no baffle & K&N pod style air filters. Any one have any idea where should we start with the main & pilot jetting?

If I remember the gross rule of thumb, I think you need to go about +2 or +3 on the mains and pilots for pods and headers, but if the thing is a straight pipe that jacks it up even leaner. May have to rich up the needles too.

From what I read, adding pods turns the bike from a riding machine into a permanent hobby of trying to dial them in.

Wired george is the expert on dialing in carburetors, I'm sure he will provide much more definitive info.

Pods flow more air than does a stock airbox. For a stcok KZ1000 with pods/pipes, suggest you start with #17.5 or #20 pilot jets after verifying the slide cut outs are 1.5. There are virtually identical versions of the VM29 that have larger cut outs and require MUCH larger pilot jets. With #17.5 pilot jets, you will only open the air screws less than 1/8 turn. If you use #20s, you can open them up to just about 1 turn. Main jet will be about #120 and the jet needle can be clipped to 3rd slot (5DL31-3).

George's numbers are pretty much what I would think should work too, you can confirm it by the plugs afterwards. That said I'm fighting with my pumper 28's on my shaft 1000 right now and it has pods with a slightly opened MAC 4-1. I have a post in electrical that pretty much has settled that something is wrong in the carbs and not the electricals.

I have tried both the 17.5's and the 20's with the main sized at 117.5's, the 20's were a bit rich but it ran well, the 17.5's are just not cutting it right now but there might be another reason for this so I wouldn't say they wouldn't work for you.

Did the owner tell you they are 29's or have you had the chance to check them yourself as they might be the stock 28 pumpers?

My kz1000ltd has 29s pods and vance and hines open exhaust I have 22.5 pilots and 120 mains and it runs nice.

Did the owner tell you they are 29's or have you had the chance to check them yourself as they might be the stock 28 pumpers?

I was told they were VM29s but I don't think so. The needle jet is a 258 0-4, the jet needle is a 5CN29 & the slide measures 31.4mm in diameter, if any one can tell me what these carbs are and maybe what year they are off of I sure would appreciate it. By the way these are pumper carbs.

Sounds like 28's but I'll check mine tonight and let you know.

George probably can tell you quicker if he checks in here before then.

Have you tried the Z1enterprises website they have a pretty detailed layout of carbs for these bikes. Does it have 3 screws on the top and are the drain plugs angled to the side.

Those are accelerator pump VM28SS from a 79/80 KZ1000A or KZ1000B. If the pump is working properly, with pods and a pipe with no baffle, they can be a bit tricky to rejet. Check to see if the pump is working by removing the #4 pod filter and opening the throttle a few times. You should see gas squirt out the nozzle. If it does, #17.5 pilots and #110 mains would be about right. I don't think you will be able to change the clip position on that jet needle as there are no slots to do so. Tune the air mixture screws for max idle. It will sound like there is little change but go for the fastest rpm on each at idle.

Last thing, when you measure a carburetor, measure the inside diameter across the venturi where it goes into the carb holder. You will find that the 28s are actually about 28.7mm diameter.

Those are accelerator pump VM28SS from a 79/80 KZ1000A or KZ1000B.

Thanks wiredgeorge for the info, the accelerator pump on these carbs is not working though.

Does anyone know the proper jetting and carb. adjustments for a *stock '79 KZ1000 E-1 at 7,000 feet above sea level?

(The only new change to the stock layout of the bike are K&N RC-2454 Universal Pod Filters)

I had previously been running EMCO Pods, and after the switch to K&N, it appears the engine revs up quicker, but when compared to the revs, the acceleration doesn't seem to match up, it seems slower than what the revs are telling me.

Any ideas or helpful suggestions from a carb. expert?

*I bought the bike only a year ago, it came with EMCO pods and I'm not sure if the carbs have been modified. Any easy way to check this?

-Thank You!

:::side bar:::
onanysunday-
i am far from an expert but to it sounds like your carbs have to be adjusted/rejetted to match the KN filters. K+N filters are high performance filters and change your air/gas mixture greatly. I'm sure the emgos looked cool but they prolly didnt effect the air intake too much. The KNs however are doing what they are made to do, suck.

sure fire way to check everything out is pull your spark plugs after riding abuot, read the plugs, they tell you if your running too rich or too lean. Then adjust your jets accordingly. I forget now, i think they say its ok to run a little on the lean side.

I've hear pods take a great deal of patience to get things just right. If it were me i'd just put the emgos back on and call it a day.

lets try not to steal any more threads huh...