Vintage Dirt Bike Q & A

Has anyone tried making their own airbox to carb boot? Is it possible for the backyard mechanic to mold their own rubber or do rubber welding to fabricate a custom boot from a stock boot?
I was told to use automotive radiator hose but every radiator hose I've ever seen had a constant diameter. Mine needs to be fat at the airbox side and narrow at the carb side. All ideas appreciated! Thx.

You could try a few things that I can think of:
1) try ebay, or vintagemx.us, or bikeboneyard.com for the original part. Patience will get it for you.
2) Use a rubber hose the diameter you need for the carb side. Then weld up a sheet metal fitting that looks like Abe Lincoln's stove pipe hat with not top on it. Pop rivet the brim into the face of the airbox, and make the tube part the size you need to slip inside the rubber tube.
3) Run a carb mount universal fit air cleaner without an air box.
4) try Googleing rubber fabrication, or check out chinasource.com for fun too.

1 doesn't require ingenuity, just patience.
2 requires some work, might remove the still-air-chamber effect of a massive dead-air space boot.
3 isn't so good for riding in the muck.
4 is tons of money

Enjoy!
Jon

I made a airbox to carb boot and run it for 2 years on a Cr125m2 out of a old car CV joint boot. Darcy

I was looking at a CV boot yesterday for that purpose. The universal ones seem the best choice because they have three step sizes on the large end and you choose the size you need and cut off the larger part. Some are really stretchy and would fit various sizes. On the carb side it looks like you could cut at the bottom of a bellows and stretch it over the carb bell. I'm trying to find one that does not taper so much because on my CR250 the carb bell is 62mm and the airbox is 68mm. It would not look like stock, but on a racer it would be OK. If I find one that works, I will list what it fits.