Mikuni problems ???

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Mark said:
didya try it with the float bowl removed or just the drain plug?

I like this idea. You can learn if the floats are working and if there is flow but:

DISCONNECT THE BATTERY....FIRST.
 
Check there is at least half a tank of fuel to well cover fuel tap screens. As fuel lines will/ may have a "loop" and possibly create an airlock. Be sure that your fuel level is well above and turn both taps on to increase "gravity" pressure and eliminate air in fuel lines..

I had recent starting issues with a Mikiuni and the visible 25mm or so fuel in the tank was not enough to feed adequately.. Half a tank full cured that issue and removed the "airlock" which wasnt helping :D :D :D
 
You mentioned you've torn the carb down. There is a little more to it, cleaning, inspection, verifying flow, etc. The VM Mik is stone reliable and easily repairable. Any friend who has more carb experience available to help?

Fuel not coming in means the passage is plugged with a HUGE chunk of shit (thread sealant or tank sealer comes to mind on a newly rebuilt bike), or, inlet seat is plugged, or needle stuck, or float height grossly misadjusted, (improper assembly is VERY common) etc. SOME VM's were equipped with a fine mesh screen above the inlet seat. Dismantle carefully (using the proper tools, JIS Phillips, 1/8" panel screwdriver for pilot jet, 6 point metric sockets, plastic drift to remove needle jet), thoroughly and verify flow through every passage with aerosol solvent (brake cleaner). If you're unsure where the passages lead, or SHOULD lead, review the diagram here. http://www.mikuni.com/pdf/vmmanual.pdf
 
If this VM has the black individual floats, I have seen them installed upside down, and cuting off the fuel supply
 
Yes

Blow air into a hose connected to the empty carb.

Then turn the carb upside down to see if the float shuts off the air.
 
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