Carburetor boring in Wellington?

[Sable]

I've got a pair of Mikuni VM28s that I'm looking to have bored out a bit as a potentially easier and cheaper option to tracking down a pair of VM32s. Can anyone recommend a guy? Also, information on what's involved would be appreciated, always good to learn

[Grumph]

While boring of carb throats can be done - and i've done it many times - I don't recommend it.

The boring should be done above the existing center line so as not to take material off the bottom of the bore. If the bottom is touched you can seriously compromise the idle holes and possibly the area where the slide rests when closed. It aint easy.

For a road bike 2mm is nothing - and given you will almost certainly have to source different needles and go through a lengthy setting up process, I wouldn't do it.
Stick with what you've got.

[pete-blen]

Also, information on what's involved would be appreciated, always good to learn

I done a Amal aclohol carb years ago for a MK3 Westlake speedway engine..
just put it in a lathe run a boring bar though.. finished with a 600 grit hone stone.
took it from 36mm to 38.5mm...
Smear a good coat of grease over the inside of the bore... stops any any alloy swarth
getting stuck down any of those small holes... make certain the holes are filled covered
in grease...

PS... the dia of the slide is the biggest yer can go... slightly smaller is better..

[F5 Dave]

For something precision & MC related Karl at Cemack in petone would be worth a try. But presumably you have the nouse to retune it for other mods you have done. Covered a bit in Graham Bells 2 stroke book, but I'm sure you already know that as you will have a copy, or will for Christmas.

[Crasherfromwayback]

For something precision & MC related Karl at Cemack in petone would be worth a try. But presumably you have the nouse to retune it for other mods you have done. Covered a bit in Graham Bells 2 stroke book, but I'm sure you already know that as you will have a copy, or will for Christmas.

+ 1 for the quality of his work.