76 KZ900A4, VM28s

Ok, These carbs have been giving me fits! I originally had two lean and two rich. I found that while tuning. Someone had drilled the hi-speed air bleeds of two carbs creating a lean condition. I drilled them all and in turn had to go to a 130 main jet. It was too fat, so I drilled the emusion tubes to further assist the air bleeds. Now it idles great and is good around town and on hard accelleration. I did have to raise the needles all the way to get rid if a part throttke lean cindition that I have been chasing since the beginning. It still has the 1/4-1/2(or a bit more) lean condition out on the highway. I am thinking I need a different needle set. Any suggestions??? :whistle:

I would change everything back to their stock settings and start there as a base line. Has the engine been modified and do you know why the air jets were drilled?

Don't know why or if the engine has mods. Don't think so. It runs so good up top and I am just trying to get rid of a part throttle issue. It has a 4-2-1 exhaust and pods. Pull very strong to around 9500. Idles liks a pussycat.....just has a cruise lean out.

try putting the fat white washer that sits on top of your needle,under the metal clip which sits in the only groove those needles have. it worked fine on my vm28ss carbs.i also put the thin washer on top of my needle. the cut-a-way on your carbs are probably #2 if you had #1.5 that would be perfect but more expensive than changing to a 5dl31 needle which would work well for your aplication. thats the same needle that comes in the 29mm smoothbores. happy jetting. oh, i am assuming your carbs are mikuni 28mm vmss and not 28mm vmsc.

The carbs already have 5DL31 needles. There are no washers on top of the needles at all, just a metal screw on retainer. They are mechanical smoothbore carbs. I don't know how to I.D. them. I was looking on the charts for Mikuni carbs and found the breakdown and was thinking on using the 5F3 needles.