GT750 34VM Mikunis

[CarbsandCylinders]

Hi guys, sorry if this question has been answered before, I searched but could not find the answer I need. I am converting my 1975 GT750 from the CV's to VM34's and I need to know what throttle cable I can use for this.

Brian

[yeadon_m]

You'll need the old style 750J/K cable, which fits the new throttle tube, but has only a 'pull' cable. This one cable opens all three carbs individually and also has a cable for the oil pump. You may find - think this is correct - that if you're replacing ganged BS40 carbs, you'll need to find a way of supporting the oil pump cable, because there's no threaded turret for it to run through, as on J/K bikes.
You'll also need the choke cable pull device, but thats easy to fit, it goes right under the clutch lever pivot bolt; and the choke cable itself, from a 750J/K bike.
Finally, you'll need eithet to fit a 3 outlet J/K fuel tap or find a way of dividing the fuel outlet from the late-750 tap into 3. The vacuum pipe goes onto the left VM32, I recall, but if incorrect that'll be obvious!
I had a bit of a play on my 750A with a set of VM32s, and while I've not done the whole installation, it looks like the VM32 slots right into the late-750 carb to engine boots, and to my surprise, the late-750 airbox slots right on as well.
May I ask why you are doing this? in my case, I bought the set of grubby VM32s because they were cheap, and I might fancy and play around in the future (either on my 750A to see if it might reduce tendency of BS40 carb'd bikes to buck and surge, or on my 550B to see if it runs differently vs stock VM28s! I had a good result fitting VM28s from a 550 onto my 380B in place of its VM24s...)
Good luck,
Mike

[pull the wire]

Hello Brian,

As Mike described, you will need the older throttle cables which includes the oil pump cable. There is an oil pump cable holder available part number 16293-31000. This part is available from Paul Miller on Ebay for about $19.00. The carb to engine boots will need to be changed to the older 750J/K style. the OEM boots are super expensive but there are some available from cruiseimage (I think) on ebay for a fraction of the OEM price. I purchased a set and they look and fit great. You will need a cable ferrule for the oil pump cable end and the oil pump cable adjuster bolt and jam nut. The 3 outlet fuel petcock is also very expensive and it is possible to split your single fuel line to feed the 3 fuel inlet ports on your VM34'S.

Hope this helps

Doug

[yeadon_m]

Doug,
You're right, I stand corrected on the 750J/K intake boots.

What would you say is a good way to split the fuel outlet into three? lots of Y-pipe connectors available, but I've not looked for 3-way pipe connectors (perhaps I should just go look )

Cheers,
Mike

[tz375]

VM34 are a much larger carb that the old zinc body VM32 fitted to J & K models. Not so much the bore which is 2mm larger but the body is larger and most significantly taller. The left and center carbs fit OK but the right carb fouls the crankcase above the clutch.

The most common solution is to machine the block to take the carbs at an angle. Next way is to machine off teh stubs and have new ones machined and welded at an angle.

It is also possible to remove part of the crankcase and have it welded back in upside down (concave) or use a set of angled intake rubbers.

[yeadon_m]

Ah, TZ, thanks...I'd misread the OP's VMs as 32, but he intends to install 34s. As I know nothing at all about these, pls ignore all my previous comments.

Cheers,
Mike

[pull the wire]

Where in the world can I find some angled intake boots? I've been looking at Honda CB750 intake boots but I hate to buy them and be the wrong size? Any ideas????

[jeff kushner]

Hey Doug,

Check these guys out. If you don't see exactly what you want, call them. I've been doing business with them for a while now and I'll vouch for them on quality and you'll see their prices probably beat anything you've seen before!


http://www.marshalldistributing.com/fil ... 33-746.pdf" onclick="window.open(this.href);return false;


jeff

[pull the wire]

Thanks Jeff! Those guy's have a lot of neat stuff. I'm sure they will have something that can work.

[Suzukidave]

Thats a great site Jeff that i havent seen before .. it went straight to my saved list

[Barry S.]

The photos are gone but maybe this will jog someone's memory a bit.

viewtopic.php?f=5&t=173&p=75265&hilit=3 ... nts#p75265" onclick="window.open(this.href);return false;

[CarbsandCylinders]

Thanks so much for all the posts. Teazer had explained to me already about the clearance problem (on DTT) and now I am not sure of what to do. I have some old 32's, can I bore them out to 34? Do I just keep the CV's (where do I get bigger jets?). Lots to think about.

Brian

[tz375]

Brian,
Good to see you over here. That link of Jeff's includes an angled adapter that looks much like a GS1100. Those would also work in all probability.

I just checked a few pics I had collected and I see that many appear to have just jammed the right carb in at a slight angle and tightened the bands. So far I have spotted PWK, TM and Delorto all with the right carb sitting on the clutch cover and higher than the other 2. SOmewhere here I have a picture of a bike with those GS boots - but of course I can't find it now.

[Suzukidave]

[tz375]

Dave, Is that a GS1100 intake rubber?

I finally located this picture. I think it's Cor Gerats TR750 replica from the Netherlands.



It looks like the same intake. I was looking at a friend's GS1100E a while ago and noticed that the CV carbs are similar BS series to the GT and they are angled, so I purchased one new intake rubber and have not got around to trying it to see if it would work with 34mm carbs.