Mikuni VM Round Slide 34mm

Mattx2

Mattx2

Build it, don't buy it!!
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Hey guys,

So , im looking to buy new carbs for the ol' XS.

Anyone have a set of these?
-is it easy to sync
-do they perform well
-easy to maintain

:confused: im lost on carbs...
I just want to kick and ride :bike:
 
The stock carbs should provide kick and ride performance if clean and jetted properly. You also need to make sure everything else is in good shape and adjusted properly.

The 34mm VM's are easy enough to sync, perform well enough (I hear other carbs are better), and are extremely easy to maintain and rejet. Being easy to take on and off, rejet, and clean are probably the best part about them.
 
Thank for the the tips travis!

Im just having way to many problems with my carbs. There crazy clean nothing clogged everything right and adjusted and still the right carb just wont run right, cant sync and are just too much trouble. Im frustrated and done messing with 'em.
 
Well if you decide to go with a set of 34mm VM Minkunis, I'd get them from MMM at 650central. Tell him what you're running for air filters and exhaust and they'll come jetted pretty close. When I got mine, I put them on and it started first kick. After you get them, take one apart and you'll be amazed at how simple they are.
 
Mattx2, if you're "lost on carbs" the very last thing you want to do is to install aftermarket carburetors. I used VM34 and VM36 carbs for years, before switching to TM36/68 4-stroke pumpers. Travis is right, MMM is the guy to get them from if you just have to have them, but you'll still have a lot of work to do in fitment, adjustment and tuning. Re. synch, with the VM's you're getting two adjustments for the price of one. Idle speed and idle synch are set with the throttle stop screws, then lift synch has to be set with the carb top adjustors. If you're going to throw that kind of money at the carbies and aren't really interested in performance mods, you might consider having your OEM units professionally rebuilt.
 
Just thought I would throw this in. I fought with the stock carbs on my '79 Special II for a couple of years, taking them off several times and giving them what I thought was a thorough cleaning. The bike would run but the carbs were never just right. I bought an ultrasonic cleaner and cleaned them one more time- problem solved.
 
grizld1 said:
Mattx2, if you're "lost on carbs" the very last thing you want to do is to install aftermarket carburetors. I used VM34 and VM36 carbs for years, before switching to TM36/68 4-stroke pumpers. Travis is right, MMM is the guy to get them from if you just have to have them, but you'll still have a lot of work to do in fitment, adjustment and tuning. Re. synch, with the VM's you're getting two adjustments for the price of one. Idle speed and idle synch are set with the throttle stop screws, then lift synch has to be set with the carb top adjustors. If you're going to throw that kind of money at the carbies and aren't really interested in performance mods, you might consider having your OEM units professionally rebuilt.
Click to expand...

I know you have probably done a thread on the TM carbs somewhere. If so, would you point us to it?

Thanks,

John
 
Carb board at XS650 Garage, back in March. If you have trouble finding it let me know and I'll post the full URL.

There are two "flavors" of TM carbies, John. One is the dual-use (2-stroke or 4-stoke) flat slide series with cable-pull slides. Like the VM's, those are better for 2-stroke applications; you run into the same undesirable compromises setting up for 4-stoke fuel demands. The TM36/68 pumpers are dedicated 4-stroke carburetors--they're RS (radial smoothbore) units set up for single-cylinder applications rather than in banks of four. They're very pricey and a lot of work to reconfigure to a bank of two. Several guys have done very nice work setting up RS34 pumpers for our twins. Mikuni also makes a 34 mm. TM pumper which our Stateside distributors don't see fit to make available. These are available in kits for our machines from a German source; see www.mikuni-topham.de . Topham's also offers many parts which Sudco, Carb Parts Warehouse, and Mikuni USA don't see fit to import here.

The RS and TM pumper carbs represent the final point of Mikuni's motorcycle carburetor development before it was frozen forever by the advent of EFI systems. Tuning is remarkably easy; upstream and downstream effects of component changes are much reduced, much less change-and-compensate fiddling. With the price of carbs, push-pull cable setup, and miscellaneous bits and pieces, the bottom line price will hit well north of $750 for a pair of TM36/68's if you buy new and do your own fabrication.
 
Look on ebay for a set of rebuilts. There is a place on there that refurbs inside and out. look brand new. Or look for NOS bs38's or 34's. I have had nothing but luck with my 34's.
 
I used white vinegar at perhaps half strength with hot (not boiling) water for the first run and then followed it up with a run with Simple Green and hot water. A rinse run with hot water followed. Crud came out of those carbs that I would have sworn should not have been in there.
 
I bought a medium size jewelry type ultrasonic on eBay. It is not heated, but you will get better results with a heated solution so I just heat a pan of water. A bigger unit would be better but mine works OK - I did have to rotate the carb bodies to get coverage for all surfaces. It is very easy to use, safe for rubber parts (although I didn't put the slide diaphragms in), and best of all you don't even have to break the carbs down to their smallest components as the ultrasonic cleaning action can get into every surface.
 
I think that one is the same size as mine although mine does not have a heater. The depth is only three inches which is why you can't fully imerse the carb without repositioning it. A bigger one would be better but I think they were a lot more money, at least when I was looking. I would not run carb cleaner in an ultrasonic cleaner, you don't need it anyway.
 

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