[fredgold52]

I just found out today from talking with people on the phone that the needle in my 28mm Micarb is not the same needle as was in a 28mm Mikuni years ago before all the EPA stuff hit town.

I would like to richen up the mid range and have already raised the needle to its max position.  It would do better if it had a tapered needle in it with a tube that matched it.  Does anyone have an idea of what I should be looking for needle and tube wise from Sudco or similar vendor?

Thanks,
Fred

[t120rbullet]

The needle and jet are out of the old VM22 carb that Mikuni used to make. The 28mm Micarb is almost a direct copy of that carb with a larger bore.
The needle in the Micarb is a 4DH7 and the needle jet is a O-8.
You can use the Mikuni 175 series needle jets in the Micarb. The next size richer from the O-8 is a P-0 then P-1 and so on.

Now the down side, the 175 series jets use the hex jets not the round jets that the Micarb use. The hex jets flow quite a bit different than the round ones do.
A 120 round jet would equal a 170 hex. A 130 round would equal a 200 hex.

Now for the real down side. None of the Mikuni VM22 needles are available today and have not been available for a long time. The Mikuni VM28 needles are about 3/8 to 1/2 of an inch shorter than the Micarbs needles and cannot be used in the 28mm Micarb.

A few things that might be an option, the 535 that RE made for a few years had a different needle in it and you might find one of them.
A few folks have made their own needles, you could try that or turn a stock needle down a bit.

There is a richer slide for the Micarb, the 2.5. That worked for me.
Best of luck,
CJ







 

[fredgold52]

Thanks for all the information CJ.  It's way more than I was expecting.  This looks like more of a long term project for when I have a lot of time to do the research.

IOn the meantime, I guess I'll stick with what I have.  It seems to run pretty well, but it does take a long time to warm up to the point where there is no 'gasping for fuel' point in the throttle travel.

[t120rbullet]

Most air cooled motors are cold blooded, as long as it runs good when it's warmed up is what counts.
Let me know what you come up with in your quest for info. I've been copy and pasting info for years and can always use more.
CJ

[t120rbullet]

Fred,
I just got CMW's new catalog and I see they have needle jets in P0 through P4 listed.
Bleed Type ones at that!
Did you ever have any luck finding a needle?
CJ

[fredgold52]

No, I stopped looking for now.  Since it has been a little warmer, the bike is running well.  I don't have much in the way of mods that would necessitate a different (better) needle.  K&N filter, no PAV, drilled bazooka.  I don't have the carb dialed in quite yet, but since it's running a little rich, I'm not in a big hurry.

I saw the different jets and needles - very encouraging.  I'll probably go further with it this Summer.