Mikuni VM28 Round Slide 28mm Carburetor

Additional Information

• Hi. Is this carb suitable for a 2 stroke? I read the 182 needle jets are for 4 strokes. In that case, can it be changed to 176 series?. Thanks

  Some consider primary style needle jets as 2-stroke specific, but they are often successfully used with 4-strokes as well. The 182 series is a primary style needle jet. Bleed style on the other hand should be used with 4-strokes only for the most part.

  Answer by: Web Support (Admin) on Jan 14, 2016 2:22:00 PM

• I have a 1998 Ural 650. Specs say 28mm carb. Will this round sided 28mm Mikuni work? There are 35mm mikunis on it now and it sure runs crappy. Thanks Greg.

  We don't carry any pre-jetted carbs or kits specifically for the Ural. But from my general knowledge with building kits for motorcycles - and knowing how a Ural performs, a 35mm Mikuni is way too big. To add to your problem, these carbs may not be genuine Mikunis - but a Chinese knockoff. Those never work well.
  A 28mm carb is about the size I'd use on a 650 and you might even be able to use a 30mm if necessary for fitment. Most BMW R60s (600cc) use 26 and 28mm carbs. But it is always better to be a bit too small rather than too large.
  We only sell genuine Mikuni aftermarket carbs. These carbs are for universal fitment and there are sizes that can fit a wide variety of motorcycles, usually with minor jetting modifications.
  First, you would need to determine the size of the manifold spigot and intake bell on your carb and then compare it to our VM28-49. This carb has a 35mm manifold spigot (the part that fits into the rubber manifold adapter), and a 44mm intake bell (the part that fits the air boot). The air boot is not a huge concern, as there are always pod filters made for these sizes. If the spigot measurement does not match, you can always have adapter rings machined for a relatively small price.
  I have attached an article I wrote on choosing an aftermarket carb. It addresses considerations you will run up against when swapping carbs. I believe this might help you. Please let me know if you have any additional questions. You can contact me at rick@nichecycle.com
  http://www.vintagebikebuilder.com/choosing-aftermarket-carbs.html

  Answer by: rick c (Admin) on Aug 23, 2018 9:17:00 AM

• I’m looking for a replacement for my 79 dt250f. I have a couple questions. Is there a port for the oil pump to connect to? And my current jetting is 50 for the pilot, 150 for the main. Can I order with that configuration?
  Thanks!

  No, an oil injection port is not on the carb body. We sell the jetting separately, only. You would need to buy and install the different jetting on your own.

  Answer by: Web Support (Admin) on Sep 9, 2021 12:46:00 PM

• Looking for a replacement carb for my 1975 DT250B. I believe it has a VM28SS now. Is this carb a close fit?

  I have a 1976 DT250 and I can tell you from experience that the carbs close, but not the same. Some of the jetting components are interchangeable. The VM28SS is an OEM carb based on the VM28 we sell, but with very specific modifications to meet the needs of the DT250. That being said, may people have used the VM28-49 round slide.
  Some obvious differences include the choke lever being located on the opposite side, as well as the fuel/air mixture screw. I am not sure if the size of the engine-side spigot and intake bell are the same. We have those dimensions on our listings and you can compare them to your stock carb. Some of the earlier DT's had oil injection ports in the carb. I don't thank that is the case with the 1975 model.
  If you have the original jetting and component sizes (throttle slide, jet needle) we can probably come very close to matching them. We have done this with other SS carbs on Yamahas (see link below). I have posted a few links that may help you. If you have any other questions, please contact me at rick@nichecycle.com
  http://www.nichecycle.com/ncs/mikuni/carburetors/mikuni-vm28-round-slide-28mm-carburetor.html
  
  http://www.nichecycle.com/ncs/categories/carburetor/mikuni-rebuild-kits/cry-42669-yamaha-dt250-carburetor-
  rebuild-kit-by-ncs.html
  
  http://www.vintagebikebuilder.com/vm38ss-vm38-9-comparison.html
  
  http://www.vintagebikebuilder.com/1976-yamaha-dt250.html
  
  http://www.vintagebikebuilder.com/mikuni-tuning-and-jetting-guide.html
  

  Answer by: rick c (Admin) on Dec 20, 2019 12:15:00 PM

• Looking to purchase this carb for a 1977 Honda MR175. What changes do you recommend or is it fine to bolt in and use as is?

  More than likely, this carburetor will not fit as is. At a minimum it will need to be properly jetted and tuned. Before you purchase an aftermarket carb, please take a look at the considerations in this article on choosing an aftermarket carb: http://www.vintagebikebuilder.com/choosing-aftermarket-carbs.html
  

  Answer by: rick c (Admin) on Apr 16, 2018 12:45:00 PM

• I am going to use this VM28 on my RD350 twin, is there Left and right carburetor available?
  if No, what about interconnection between two carburetor and choke position of both carburetors?

  There is no left or right carburetor, so the idle adjustment will be on the left for both carbs and the fuel/air mixture screw will be on the right for both carbs (facing forward). Access for the choke also will always be on the left side. Most bikes with dual carburetors can be started using just one carb (especially two strokes). Even with the choke on the inside, the choke lever can usually still be accessed. Unless you engineer one, there will be no interconnection between the carbs.

  Answer by: rick c (Admin) on Mar 5, 2018 3:11:00 PM

• Do you have the rubber spigots to fit this to a clamp style intake manifold. Basically a piece of round rubber with a clamp on both sides. The inside diameter on one side is 40mm and 35mm on the other side.
  
  Thanks, Bill

  William,
  
  We don’t have rubbers that step down like you describe. I am not sure where you can find something like that. I imagine it would be easier to use a spacer on the carb side to bring the OD up to 40mm, and then use a straight piece of green stripe radiator hose or similar.
  

  Answer by: Web Support (Admin) on Sep 30, 2015 11:35:00 AM

• Hi, do you also have the RHS carb for a Yamaha RD400C? That doesn't have the choke lever but connects to the LHS carb via a tube?

  Thanks for your question. We only sell Mikuni factory-made aftermarket carburetors. We do not sell any OEM carburetors. In many cases, these aftermarket carbs have very similar or exact specifications to OEM carbs, but there may be a few subtle differences. For instance, there may be a choke lever rather than a cable operated choke, or the idle adjustment screw may be located on the opposite side of the OEM version. Since the OEM carburetors are often unavailable or very expensive, people turn to these aftermarket carbs for a solution.

  Answer by: rick c (Admin) on Jan 9, 2017 11:47:00 AM

• i want to purchase a set of mikuni vm 28 carburetor both right and left. i can see only left with choke switch. is it possible to keep as left and right , if i buy 2 pcs? is it suitable for yamaha rd 350

  When it comes to the flat slide carbs, only one side is available. For Mikuni, when a left and a right is offered, the only actual difference is the location of the idle adjustment screw. Everything else is exactly the same. I dont think it will cause too much of an issue on an RD350. We plan to create a carburetor kit for the RD350 and RD400 using these same 28mm carburetors. They should be a pretty good match for that engine.

  Answer by: Web Support (Admin) on Mar 21, 2017 4:16:00 PM