Mikuni VM20 Round Slide 20mm Carburetor

Additional Information

• could these be fitted on a honda cb350?
  
  

  The VM20 would not be a good choice for the CB350 because it is not big enough to meet the needs of the engine. I would suggest a VM28 if your bike is mostly stock. We have a great kit for the CB that is pre-jetted for the stock CB. It also includes throttle cables and pod filters - all things you would need to buy.
  This kit has been successfully tested by us and we've sold it to dozens of satisfied customers over the years. A big bonus to using our kit is you don't have to spend hours attempting to dial in the jetting - which also includes buying an array of jets and spark plugs for testing.
  I've attached a link below:
  http://www.nichecycle.com/ncs/mikuni/carb-kits/ncs245-honda-cb350-cl350-cb360-28mm-carb-kit-by-ncs.html

  Answer by: rick c (Admin) on Mar 27, 2019 9:37:00 AM

• What's this jetted for? What jets would you recommend for this carb on a '75 Yamaha RS100?

  This VM20 is a universal, aftermarket carb and is not jetted for any particular application. These carbs are meant to be re-jetted when purchased. It is difficult to determine if this carb will fit without having the bike in our presence. Mikuni does not offer any kind of guideline for the fitment of their universal carbs on different brands and types of motorcycles. We have found it is always best to duplicate, as closely as possible, the original equipment carb. I have attached a guideline to selecting an aftermarket carb. This will help you determine if this carb is right for you. Please keep in mind that the specifications and measurements for our carburetors are in the listing online.
  I have also attached a Mikuni tuning and jetting guide. If you purchase an aftermarket carb, this manual will help you select the correct jetting.
  http://www.vintagebikebuilder.com/choosing-aftermarket-carbs.html
  http://www.vintagebikebuilder.com/mikuni-tuning-and-jetting-guide.html
  Once you have taken a look at these guides, please let me know if you have any specific questions. I can be reached at rick@nichecycle.com.

  Answer by: rick c (Admin) on Apr 22, 2019 3:25:00 PM

• I purchased this carb form you. The problem is that main jet is NOT 4/042 like it says! Pilot is correct thought. Main jet is this big ass long monster size jet!! Jets 38.5mm long!! Letters on side of this thing are 239 0-6. What the hell size is this? I'm a little frustrated because I purchased this carb because of main jets were advertised to be 4/042 !

  The VM20-273 is pre-jetted at the factory with a VM4/042-180 jet installed. Unlike other Mikunis, the main jet is installed at base of the float bowl. If you unscrew the float drain (hex-head screw) you will find the standard Mikuni VM4/042 main jet attached to this special screw. This screw doubles as a jet extender/holder. What you are describing in your question is not a "giant" main jet, but a 239 series needle jet. Unfortunately, Mikuni makes just this one needle jet and does not offer any other sizes.

  Answer by: rick c (Admin) on Jun 14, 2019 9:26:00 AM