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Discussion Starter · #1 ·
What bronze do you recommend for valve guides? We just made one out of 660 but was told that 630 or ampco 45 is the way to go. I cant find any ampco 45 for sale but online metals has the 630.

Also need to ask how your removing your valve seats. There's the machine out method and was told you could weld onto them, when the weld cools it will shrink out the guide enough to tap out w a drift.

Thanks,
Toby
 

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Discussion Starter · #3 · (Edited)
66-68 Motobi/Benelli Barracuda 250cc OHV 4 stroke, italian light weight thumper, aluminum head/barrell/cases

Original guides are def bronze or brass alloy, cant tell the exact makeup but they are splintered bad on the CC side. After a little research I'd guess the stock guides are manganese bronze. I read an article about how the Europeans used a lot of it. It was a really cheap material and easy to work with. Didnt seem to last but it was cheap to fix. I'll post some pics of the carnage later.
 

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Discussion Starter · #7 ·
DUDE! WHAT? lets get some pics of this thing!! sorry i cant help in the materials dept, but oh my god, please share your project!
Sorry man, its completely dissasembled and in a crate, not much to show right now. I had it shipped to Texas from CALi. I really need to get organized and start a build post on it. It came with a race frame with custom trees and rear sets. Its gonna be the bidness once its together. I already have a 125 5 speed and liked it enough to find a 250. Here's the 125.

 

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Discussion Starter · #8 ·
I have used diesel Ford tractor valve guides as a template. If you are making your own, I assume you have the equipment to turn them down to shape and bore/ream them. I have a bunch of these cast iron guides I would be glad to ship a few off to you to work on.

Check out my thread: http://jockeyjournal.com/forum/showthread.php?t=93016 it details how I fixed an enlarged guide hole with the very guide I am talking about. Worked like a charm.
Thanks for the offer. I ended up ordering 1' of bronze alloy from onlinemetals.com. Were gonna work it out. My neighbor is a retired machinist and keeps himself busy helping punk kids like me. He got bored over the weekend and made a guide from 660 just to see whats involved. He's a saint. I took him the motor today and he's going to make a couple gear pullers so we can split the cases. The pinion and cam gears are helical and the teeth are easy to chip with a normal puller.
 
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