boring out smoothbore carburetors?

[makenzie71]

I've seen a bit of hub bub about swapping to other GS model carbs to get the bigger bores and it made me wonder a bit about why not just bore out the stock 26mm carbs? There's plenty of room to get up to 29~30mm without worrying about sidewall thickness.

Comments?

[SqDancerLynn1]

I have seen people claiming to bore them to 28mm Never seen one

[makenzie71]

I'm going to throw my buggered up one on the lathe next week and see how far it can go. It looks like we can get 30mm, max, out of them before sidewall becomes an issue, but I can't tell if there's anything inside yet that'll cause concern.

[Nessism]

[makenzie71]

How much did you get out of them? Also, how fast did you spin the bodies and what was your feed? I'm worried about it wanting to wobble a bit and I'm not really used to cutting something soft (usually stainless).

[Nessism]

How much did you get out of them? Also, how fast did you spin the bodies and what was your feed? I'm worried about it wanting to wobble a bit and I'm not really used to cutting something soft (usually stainless).

Didn't bore any myself, just found a nice photo.

[heathen]

my guess on speed and feed would be less than 250 rpm and somewhere around .002 per rev. the reason for the low rpm is if something goes wrong you wont shoot it across the shop. nomally on aluminum you can run rpm wide open and feed depends on what you want your finish to look like. i would also use a .015 radius on your cutting tool. if you can get a good hold on the carb in the chuck without damaging it you can run it faster.

[Shaughn]

That's no Hobby Unit There

nevermind . . .

[TheCafeKid]

my guess on speed and feed would be less than 250 rpm and somewhere around .002 per rev. the reason for the low rpm is if something goes wrong you wont shoot it across the shop. nomally on aluminum you can run rpm wide open and feed depends on what you want your finish to look like. i would also use a .015 radius on your cutting tool. if you can get a good hold on the carb in the chuck without damaging it you can run it faster.

They ARENT made of alu tho. Its mostly ZINC.

[makenzie71]

Soft all the same. I think I can get a good bite on the carb without damaging it...we'll see. I'm just hoping I don't see any balance issues and that our little boring bar doesn't walk.

[chef1366]

Good luck with that! I'll be interested in how it turns out.

[terry]

I've got some old carbs laying around, I might stick one in the lathe and see how it goes! Cheers, Terry.

[TheCafeKid]

One of these days...carbs made from harden carbon ceramic. It would work! Why? Just cause it would be cool...