Carb Boring???

[cr480r]

Anybody have any information or secrets they would like to share??

[Daddio]

I never thought that carbs were boring, I always thought they were interesting. shens
Sorry I couldn't help myself.
I'm not sure how it's done but I'm sure someone will know.

[SWIGIN]

i have done it to a few, no real secrets that i know of othe rthen you must keep the bore smaller then the slide.

[Billy Golightly]

Theres a pretty decent section about it in Graham Bell's book, Two Stroke Performance Tuning.

Daddio hit the main part on the head. Don't bore out further then sides where the slide wont close properly, and dont bore down enough that you interfere with the area where the needle drops down into the dump tube from the main jet in the bottom of the carb.

[Daddio]

Sorry Billy but I can't take credit for that. That was swigin that had the info.
I do have a question though. What do you use to bore a carb? I'm not opposed to trying new things.

[SWIGIN]

i used a boring bar on a lathe

[Billy Golightly]

Whoops, sorry. Was kinda late last night!

[cr480r]

I guess what I am trying to figure out is rather or not it should be bored straight or with a taper.. and if tapered, how much? It seems to me that the venturi should be the smallest point in the intake tract, but I dont wanna ruin parts to find out...

[Black86tri-z]

there is well at least was a place in springfeild mass called rep racing that use to helical bore all my carbs for me back in the day when i use to do water cross,i was cheating so to say it was noticable faster

[Black86tri-z]

it was wicked cheap to like 40 a carb

[cr480r]

anybody want to share thier carb boring secrets? I have a spare PWK i wanna bore to 41.5...

[factoryX]

my 36mm pwk is bored to a 38mm by duncan racing.

[x.system]

anybody want to share thier carb boring secrets? I have a spare PWK i wanna bore to 41.5...

Taper bore, I was going to do one of mine but found one of esr's 40.5 so I just went that route. I researched it and my motor builder also confirmered they need a taper for best performance. There also may be a reason the biggest you can get is a 40.5 with that body so you may want to start there. I'd like to see how it comes out though and what you end up with.

[cr480r]

Thanks for the input x.system... It makes sense to me that it should have a taper.. but i am curious of what is ideal. Maybe I should measure my 38 and 39.5 and see what they use.. I have a spare 38 that I want to sacrifice to the cause..