Starter (choke) plungers

Actually 4 different styles if you count the "ribless" early 28's.

wrote:

Jim, all three versions of these choke plungers are right at 4.00mm. Chrome plated or not, all 4mm. Smoothbore is irrelevant because they used the identical ones for all the VM series. What does matter is the rubber cap if the plunger isn't returning, VM20-455 is the rubber cap Mikuni number. Is this the problem?  
 

Seeing conflicting info elsewhere on the indicated shaft diameter, 29 smoothbore vs VM28SS plungers.

 It would be an easy measurement with no disassembly needed.  Raise the plunger & measure just above the rubber plunger seal.

Thanks for the responses everyone.

Good Ridin'
slmjim & Z1BEBE
 

asphalt900 wrote:

Actually 4 different styles if you count the "ribless" early 28's.
 

What's the difference in early ribless VM28 plungers vs later VM28 plungers?  Interchangeable?

Good Ridin'
slmjim & Z1BEBE

slmjim+Z1BEBE wrote:

asphalt900 wrote:

Actually 4 different styles if you count the "ribless" early 28's.


 

What's the difference in early ribless VM28 plungers vs later VM28 plungers?  Interchangeable?

Good Ridin'
slmjim & Z1BEBE

All these VM plungers are pretty much the same at the business end with an 8mm diameter plunger head and the only variation there being the length of the metering pin which doesn't affect their function.
All variations will physically fit and work in the body of any of the VM series carbs.
The main differences are shaft length and profile of the VM/SC versions ( 2 bolt top )  at the lifter end to accommodate the different lifter arm and bobbin types which can be accounted for with either mixing and matching or modifying lifter arms and bobbins.
All VM/SS plungers from the VM22,24,26,and 28mm ( 3 bolt top ) carb banks are the same except for the finish in either plated or plain brass.

 

Simjim, I installed a set of the later vm plungers in the early carbs, longer shaft used the spool nylons and later lifting arms, for lift and lowering, bought a bunch from niche or jets r us, for other bike, longer shaft was used mid 74 and up, which you probably know

 

Soo unique the ribless choke plungers are, they Don't interchange. Altercations of the lifters would be required, believe me i've tried it. The castings sit in a different position relative to choke rod and lifters even though the holder plate was the same part number.