mikuni vm 34 parts source

I'm still new here and the norton I have came with a 34mm mikuni vm34 round slide carb , since it sat for 10 to 15 years prior to my purchase it was a tad dirty, after a through cleaning it's as good as new. However I will need to replace the floats as well as all the "soft" parts float bowl gasket O rings etc. does anyone here know of a good source for mikuni vm34 parts ? Thanks Ray

MAP cycles

thanks guys

update on the vm34 carb that came with this bike. I've found all the bits and pieces I needed to rebuild this carb. I got a new set of plugs champion n7y's and got the engine to start but take gas it will not do , I set the throttle setting at 1 and a half turns on the air screw & just a slight lift on the slide screw. choked it & kicked twice, turned on the ignition & she fired but doesn't seem to want to take gas ??? what am I doing wrong ?? I also set the points & have good spark so I am at a loss as to what to do next. help
Thanks Ray Oh btw I've got 120 on both cylinders & the engine sounds very healthy !!!! changed all the fluids 20 wt. for now since it's been sitting for 15 years & 80/90 gear oil in the primary . thanks again Ray

krazyray said:

...I set the throttle setting at 1 and a half turns on the air screw & just a slight lift on the slide screw. choked it & kicked twice, turned on the ignition & she fired but doesn't seem to want to take gas ???

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All of the fuel up to around 1/4 throttle (that includes while you're cruising on level ground) is handled by the pilot jet. What you're seeing is not "taking the gas", but actually going lean when you open the throttle, since the pilot jet and/or its passages are most likely plugged. It idles while on "choke" (actually, a fuel enrichment circuit on the Mickey), since that artificially adds fuel to the idle circuit. You probably have around a 35 to 40 (0.35-0.40 millimeter) pilot jet, and they can be very difficult to clean. Resist the temptation to use a wire to clear it, since that can alter its flow characteristics. Soak it (the pilot jet only) in a good, strong carb cleaner (dip) overnight, then use compressed air to make sure it's cleared.

krazyray said:

...80/90 gear oil in the primary.

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I believe the consensus is to run F-type ATF in the primary, since gear oil will render the clutch virtually useless. 80/90 is great for the gearbox, though... Just a typo? Nathan

When you "choke" the Mikuni you are opening a separate intake with its own fuel route.
If you crack open the throttle even a little when the bike first fires you will kill the engine!
When the engine fires leave the throttle fully closed.
After a few seconds you can slowly feed in some throttle and back off the "choke'.
If it starts to stumble put the choke back in until it has warmed a little more before adding throttle and taking off "choke".

ok soaking the carb again ( overnite) I will blow it out & see what happens ? let ya know . drained the 80/90 gear oil from the primary chain case will remove the outer cover & clean & replace the fluids with "F" type atf 200cc's , I hope this works btw the existing battery is stone cold dead & my new one isn't here yet , will that make any difference at all ??

thanks Ray

krazyray said:

ok soaking the carb again ( overnite) I will blow it out & see what happens ? let ya know . drained the 80/90 gear oil from the primary chain case will remove the outer cover & clean & replace the fluids with "F" type atf 200cc's , I hope this works btw the existing battery is stone cold dead & my new one isn't here yet , will that make any difference at all ??

thanks Ray

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You'll need to do more than soak/blow... use small wire ti clean out ALL passages, verify flow with spray solvent. Do them all.

Get yourself a DynoDave clutch pushrod seal... slickest little answer to that problem. http://atlanticgreen.com/ndnsclutch.htm read, then scroll all the way down.

Use jumper cables to a car battery to test fire the bike while you wait for your batt to come. Pay close attention to polarity, is you bike still positive earth? or converted neg?

All carb passages are clear as far as I can tell , jets (all) carb body & float bowl ( soaked ,blown & cleaned w/ carb cleaner all are clear. so far so good.
drained the 80/90 out of the primary, removed the outer cover cleaned ( not a speck of dirt anywhere ( wiped & dried with paper towel )
now!!!! then ...... the primary chain is sooooooo tight it's about ready to pop. ( not good ) as according to my research I should have 3/8 slop . so tell me if I have this correct.
loosen the bottom trans bolts then adjust the adjuster to achieve 3/8 slop in the chain . then tighten to 70 ftlbs on the lower blots. however the manual says not to touch the left adjuster nut. I stand confused & I can't find a picture of what I am trying to accomplish anywhere.
so I guess I looking for primary chain adjustment procedure w/ pictures 1972 750cc roadster
I don't want to reassemble without proper adjustment. oh & I bookmarked dynodave's page for future reference when I get that far.



thanks again Ray