Vm34

i Just ordered some vm34 mikuni carbs. I got them from dime city. It does come with the 1 to 2 cable. I was wondering there was a way or has anybody done a single cable with a linkage( or a ball end link) to run both without the cable split.

You may not like to hear this, but most likely regular VMs cannot be linked without zome serious engineering and machining. Some oem VMs on 70s japanese fours were linked, but they were mostly 28 mm or smaller. However, TM/RS 34 for the XS are linked, but cost a bit compared to generic VMs.

I run the split cable...works good...and VM's are super easy to tune and set cable slack.

Right, you can't modify carb bodies made with cable pull actuation for a shaft-and-bellcrank system. What signifies in carb size is the unobstructed area of the venturi (throat), and a 33 mm. straight-through carburetor provides nearly as much unobstructed area as a stock BS38. Although no longer available new, the Mikuni VM33 is a bell crank carburetor that was original equipment on a number of "superbikes" in the late '70s and '80s, and good used samples are fairly common. You'd need to fabricate brackets and a throttle shaft for the XS650's 120 mm. carb spacing and do some jetting, but since the VM33 was set up only for 4-stroke applications the jetting task should be fairly straightforward.

Thanks. Was not sure. Thanks for helping a noob out.

I found my set of 34s the other day. Been meaning to measure the travel required to pull the slide to the top.

On my race bike back in the 70's I started with the stock 74 dual cable throttle housing. Then moved to a rd350 throttle cable with the oil pump cable removed. the rd setup worked much better for keeping the carbs synced. I think the rd cable is much better than the cable that was supplied with your carbs if it is the same as the mikes cable I have.

The VM's require a longer cable pull than the the stock carbs. I replace the stock TX throttle with a throttle that had a larger drum for the cable. I think it may have been from a xt500.The stock BS38 have a lever on the carbs that doesn't require as much rotation of the throttle. My wrist didn't bend enough to get full throttle.

My kit came from dime city cycles. It come with a 42 inch(case length) 1 to 2 cable. I don’t know if it will be long enough.

grizld1 said:

Right, you can't modify carb bodies made with cable pull actuation for a shaft-and-bellcrank system. What signifies in carb size is the unobstructed area of the venturi (throat), and a 33 mm. straight-through carburetor provides nearly as much unobstructed area as a stock BS38. Although no longer available new, the Mikuni VM33 is a bell crank carburetor that was original equipment on a number of "superbikes" in the late '70s and '80s, and good used samples are fairly common. You'd need to fabricate brackets and a throttle shaft for the XS650's 120 mm. carb spacing and do some jetting, but since the VM33 was set up only for 4-stroke applications the jetting task should be fairly straightforward.

Click to expand...

Grizld,
I had to look up KZ1000MK2 and GS1000E specs, to see if my memory was correct, and found that both had 28 mm slide carbs, VM type. XS1100 had CV carbs from the beginning, just as later Kawasakis and Suzukis, as well as the Honda CB900F. So what bikes had VM33? Or was that a popular aftermarket upgrade? Keihin CR33 definitely would be
I also seem to remember a lot of talk about VM29 Smoothbore carbs for the large fours back then, as a popular carb setup.

Maybe I was mistaken, and the VM33 was aftermarket only?

One caveat: ebay vendors are hawking "VM33" cable top carbs, but I suspect that those are knockoffs. As far as I know the only 33 mm. VM carbs by Mikuni were round slide bellcrank carbs with accelerator pumps, sold in banks of four.