New/possibly larger carb for 01 Dirt Squirt

[Antique 1]

First post. Going to be re-building my 01 Dirt Squirt motor in the near future, which I'm sure I will need help with, but I know the stock 26 mikuni was pretty much junk when I got the bike. I would like to give the bike a bit more snot, maybe a little port work too. Thinking about a 28 or 30 mm. Any thoughts ??

[matt glascock]

The bike was engineered (well) to run best with the VM26 carburetor. Without significant port work, a larger carburetor will see slower air velocity through the pilot circuit and across the venturi and a weaker signal. You might get a bump at WOT, but the low end and transitioning through the different circuits will probably suffer most likely resulting in a sag in the midrange. You might be able to tune some of that out on the VM28, but unless you are planning on porting the motor, best to stick with the VM26. What kind of riding will the bike be used for? All-out MX, go with the 30mm and port the crap out of the motor. Play bike/trailing? Go stock. As a rule of thumb, the more you pump up the motor with carburetion, porting, head shaving, case stuffing, etc, the more fiddley it will be to get dialed in at the track every time you race.

[Antique 1]

Thanks for the quick reply. My thought was to build a little bit of a hot rod. I've painted it Ford tangerine orange with a Ford engine blue frame, kind of a Super Combat clone, and sourced a Torque Engineering down pipe as well. It won't be raced, just a little piece of jewelry to be ridden around at vintage bike meets by me and my buddies, all in our 60's.

[matt glascock]

Sweet. VM28, mild porting, you'll be set. My toaster tank SR has a similar set-up right down to the pipe and it RIPS. If you, or someone you know has good welding chops, you might consider converting your low pipe to a high right-side mount. Hodaka Dave did that conversion for me and I love it. It really tucks in nicely and he included a nice wire mesh heat shield. Although its set up for MX, with the reed valve induction, its been a pretty cool woods weapon on more than a few occasions.