A video of the Hawk that I now have a stock motor on

[Bill Hilly]

It runs good, and makes the expected power, but it will kinda pop between gear changes sometimes, especially on light -medium acceleration. There is a spot on this video between 14.10, and 14.30 or so that shows what I mean. I have a Nibbi pod filter, aftermarket exhaust. It has a VM26 with 110 main, and 25 pilot ( I had accidentally said125 pilot). Do you think it's because of my mixture?, or the needle? Thanks

[bigdano711]

What is the VM26? Mikuni? You say you have a 110 main and a 125 pilot. Are you sure on that pilot number? Where is your needle position and how many turns out on the air/fuel mixture screw?


My laymen's guess is it has something to do with the idle circuit assuming you are returning the throttle to idle between shifts.

[Bill Hilly]

Originally Posted by bigdano711

What is the VM26? Mikuni? You say you have a 110 main and a 125 pilot. Are you sure on that pilot number? Where is your needle position and how many turns out on the air/fuel mixture screw?


My laymen's guess is it has something to do with the idle circuit assuming you are returning the throttle to idle between shifts.

The VM26 Mikuni style is nearly identical to the stock carb, and is the same size even though it's called a 26. Other than having one extra bolt holding the fuel bowl on, it's hard to tell them apart. They use Mikuni style jets, which are available. The pilot jets on them are sized different than some others. Some are sized by the size of the jets opening, and some by the how much they can flow. The 25 is actually pretty common for the VM 26 used on these bikes, probably about like a 38 pilot in a Nibbi, or PZ. . My mixture is out probably about 1.75, or 2 turns out. They have the hard to reach mixture screw, like the stock carb. I can turn it when the motor is cool, but it's easy to loose track of exactly how much, because you don't always know how flat bit is engaging the slot.
This carb has a very blunt needle, and I wonder is that may have something to do with it.
I just realized that I put 125 pilot, but I meant 25. LOL

[bigdano711]

I found the same thing with the Nibbi, pretty blunt needle. I tried to change to different positions with the clip and couldn't really tell a difference. When I changed to the Keihin style JJH needle, I got positive feedback on my idle, causing me to drop from 40 pilot back to 38. Do you know if the Keihin style needle will fit in your carb?

[Bill Hilly]

Originally Posted by bigdano711

I found the same thing with the Nibbi, pretty blunt needle. I tried to change to different positions with the clip and couldn't really tell a difference. When I changed to the Keihin style JJH needle, I got positive feedback on my idle, causing me to drop from 40 pilot back to 38. Do you know if the Keihin style needle will fit in your carb?

I think I have a less blunt needle in another VM26 that I have around here. The last Nibbi that I ordered was a PEZ, which is pretty much the same as a PE28FL, except it's a little smaller diameter at the air filter end, and it has a needle that's extremely thin, and tapered, almost like an actual needle. I used it on my " hot" motor, but I lowered it one position from the center, and still , I think it was a little much, because I would occasionally get the little" hiccup " if I rolled off if full throttle quickly.