Fw: [DEr's read Msg15985] Re: Mikuni Carbs
Steve Kiblinger:
Jun 26, 2013
Occasionally VM-28 roundslides show up on EBay as NOS (New Old Stock)...
There is a high time LE that has used TM-28 Flat Slides - the carb float valves had to be replaced at about 100 hours, otherwise all Ok... These carbs are available new in many places - just more expensive... Mikuni brought these carbs to provide better mid range response - doesn't matter much to us...
If you look at the Mikuni tuning manual there is a graph in there that calls out HP as PS (German for HP) as the carb sizing scale and can conclude that 24 - 26mm carbs are Ok for our purposes ( I don't know of anyone that has settled on this size and therefore am hopeful there will be feedback)... The VM26-606 is Japanese made and shows up in several vendor catalogs...
The bigger carbs are considerably heavier and will be at full power with the slide half open on a single cylinder - the upper half of the slide becomes a (dead zone)... The way the Mikuni is designed this makes tuning a daunting task because the carb ceases to function as described in the tuning manual due to the slide position determining which jets are in the driver seat - the Tuning Manual has a big diagram near the back that spells this out graphically...
There are a lot of zinc body carbs on the used market - you don't want them because of the weight...
Here's a link to the Mikuni Tuning Manual pdf:
Tune for 1300 - 1400 F EGT static RPM...
Power will be low below 1300 F...
