Request help in selecting carb for 350 engine, dirt bike

janders1957 · Post by **janders1957** » Sat Feb 26, 2005 8:40 am

I'm building a dirt bound 350. Intake port is 26mm, I'd like to blend this out to 28/30mm and fit a Mikuni. Welcome input on the porting.

Most Mikuni's are jetted for two strokes. Can anyone recommend a source for Mikuni carbs set up at least in the ball park for a 350? Or offer up slide and jetting advice so I can convert an ebay carb? Or..., is there another carb I might consider?

This bike might see a low key club race or two, but is going to be setup as street legal DP in a Maico chassis ( a Maicati! ), and longevity is more important than max performance. But I would like to boost output a bit with a larger carb. Heck, a Honda XR200 runs a 26mm, I ought to be able to run something bigger on a 350...

Thanks,

Jon

Robin172 · Post by **Robin172** » Sat Feb 26, 2005 9:05 am

Have you thought about a Mk II Amal concentric? These are often on ebay and parts can be readily purchased for them.

janders1957 · Post by **janders1957** » Sat Feb 26, 2005 10:59 am

No, I really hadn't thought about anything but a Mikuni really.
Just looked some up on ebay, have to say I've never seen one of these in person. They look like they might be a bit tall. One problem I'm going to have is fitting the carb in between the head and both the frame top tube and the tube that comes up from the swingarm pivot. I did this Ducati/Maico conversion in the 70's, and I had to replace that side tube with one that bulged out at the top to clear the carb, there really isn't much room.
But I'll ask around and see if I can borrow one locally to check the fit.

Most of what I've read about Amals relates to the old side bowl carbs and generally wasn't favorable. I was only faintly aware Amal produced more modern designs.

Thanks for the reply and mentioning Amal, I will look into them.

Jon

Robin172 · Post by **Robin172** » Sat Feb 26, 2005 12:31 pm

I have a 250 that I've road raced since '93 and I've only ever used a MK II on it. Firstly a 32mm and since '94 a 34mm smoothbore. I raced a Rotax single in the 80's and I used a Mikuni on that. Really there is not much to choose between them but I don't know about the prices of one versus the other. If you go with the Amal I'll try to find out slide, needle, jet sizes you'll need if you want me to.