28mm VM carbs

zed1015 wrote: Good score on those 28mm pumpers.
The best Mikunis of the bunch fitted to a stock bike.
Originally fitted to USA Z1R's , MK2's and possibly ST's
The triangular casting is blank and does not need any parts or cap so leave as is.
The triangle diapragm was only used on the 26mm version and funnily they were the worst of the bunch.

oh ok, thanks, I was taking a chance on them cause I don’t know a lot bout this style carb I won a bid on eBay got less than a 100 shipping included.

Ok guys, got the carbs clean in and out, reused main jet (120) pilot jet (17.5), new o rings gaskets and float valve seat and needle. So put them on the bike fired up fairly easy. My problem started when I tired to sync them, it was idling high so went to back on idle screw but it wasn’t even touching the throttle stop, so it idled down when I started adjusting each needle but then it turned into me chasing each cylinder. So I done something wrong or I missed a step so any help would be appreciated.

If the slide adjusters (sync screws) are adjusted so the slides are too far open the engine will race and the throttle stop won't be effective. You may need to go back and mechanically sync the slides lower in the carb bores.

Ok , bench sync, is there a certain cap I need to shoot for, I noticed the small cut out when the slides are all the way down, does it idle off that section?

I'm not sure exactly how far open to set the slides but lower than where you have them now would be a good starting point.

Ok I will try that tomorrow, I appreciate the advice.

They should be set at about 0.5mm to 0.7mm open, including the little space on the bottom. I use a piece of 20 gauge copper wire to set mine. You can get the wire at any Home Depot in the picture hanging wire section.

hardrockminer wrote: They should be set at about 0.5mm to 0.7mm open, including the little space on the bottom. I use a piece of 20 gauge copper wire to set mine. You can get the wire at any Home Depot in the picture hanging wire section.[/quote

Ok, do u put the wire next to the little notch or under it. I might have some of that wire laying around , I know I got fence wire and electrical wire in the garage.

I put the wire between the bottom of the venturi and the notch in the slide. Some people use 22 gauge wire. I use 20 gauge.

hi zilla i think around the 12 july this year under the carb section there is under cable adjustment heading a good write up on some vm 28 carbs ,i am also cleaning a spare set of 28mm carbs as a spare set ,you done well with yours from what they were like ,david

david richard wrote: hi zilla i think around the 12 july this year under the carb section there is under cable adjustment heading a good write up on some vm 28 carbs ,i am also cleaning a spare set of 28mm carbs as a spare set ,you done well with yours from what they
were like ,david

Thanks David, this is my first time working on or with these carbs, I’ll check out the write up, I’m gonna bench sync them and I had to order a new throttle cable the one I have want work , so I can’t drive it yet to see how it runs.

Bench carb sync