Keihin Thoughts

[wayne thais]

I recently had an issue with the Keihin PWK on my 09 3.2 4T. Hard starting when hot and dying going downhill.

Took the carb off at least 4 times, cleaned everything, set the float level and it would still spit fuel out of the overflow. I have used the Keihin on almost all of my bikes since "99" (GG TXT270) plus most of my Sherco's (several). I have never had any problem with the PWK until now. I talked to Ryan and he suggested that I carefully look at the needle seat, he has found small particles there that he had to remove with a dental pick. I took the carb off again and cleaned the seat thoroughly and reset the float (19 mm) holding it at 45 degree angle. It runs great but still occasionally spits a little bit of fuel out of the overflow. On Monday I am going to order a new needle, I noticed a slight groove on the one in the carb. In order to keep the crud out I have installed an inline filter.

It appears that the needle and set as well as the float setting is extremely critical on the Keihin.

If you are having problems with your 2.9 or 3.2 starting and running look very carefully at the needle and seat and the float setting.

Wayne

Edited March 29, 2009 by Wayne Thais

[borus]

i had the same issues on my caby plus plugging the pilot until i installed a fuel filter, since then no problem

cheers

[hemisavoy]

I have had the overflow issue with my '06 Caby as well. After exploring many avenues, including smoothing molding lines on the floats, deburing tiny sharp areas on the main jet tower where the floats may touch, and slightly moving the brass overflow tube closer to the main jet tower to avoid float interference, the thing that finally cured it for me was slightly, and I mean ever so slightly lowering the float height. I did this by trial and error till the problem was gone. I doubt I have moved it more than a mm, but it worked and I have been overflow free for more than a year. That and bumping the pilot to a 50 for my altitude has made this bike run like an electric motor.

[wayne thais]

Do you remember what you ended up with as a dimension for the float setting? The normal setting is 19mm.

[hemisavoy]

Wayne, I honestly didn't measure it. I doubt it is under 18. It was a very small amount. I was just trying to get the floats to shut off a bit earlier than they were at the 19 setting. I adjusted in very slight increments till it quit running out the overflow. It was just a bit. In my opinion only, the 19mm measurement is just a bit too much allowing the overflow to come into play.

[wayne thais]

Wayne, I honestly didn't measure it. I doubt it is under 18. It was a very small amount. I was just trying to get the floats to shut off a bit earlier than they were at the 19 setting. I adjusted in very slight increments till it quit running out the overflow. It was just a bit. In my opinion only, the 19mm measurement is just a bit too much allowing the overflow to come into play.

Correct me if I am wrong but since you are measuring with the float bowl upside down the dimension would probably be 20 rather than 18, do you agree?

Thanks,

Wayne

[hemisavoy]

I apologize Wayne. You are right. I'm thinking 180% out. I was dropping the floats in the bowl a bit so they would shut the needle off a tad bit earlier. So, yes, more like 20 instead of 19. By the way, on my Caby, the carb sits clocked a bit off center (like 11:30 instead of straight up 12:00). I don't know if your 4T is that way. Did it affect my float setting differently than it will yours? Don't know. Good luck, and I hope a tiny float adjustment will help you.