Cylinder boring machine

[Dialer]

In need of general info on cylinder boring machines. If someone was interested in starting a vintage motorcycle restoration operation, how would one go about acquiring said machinery? This is quickly becoming a lost art, as the cylinders we have that need boring are piling up, and can't find anyone in North Georgia that bores smaller cylinders (there's one guy in Lawrenceville that wants $145 per cylinder). My partner has some DEEP pockets, and is ready to purchase a used one, but I really don't know where to start. I see "milling" machines on FB Marketplace and e-bay, but none of them tell me what they do, or if they can bore cylinders. I've heard the term "boring bar", but that don't really tell me anything. I've BEEN to boring bars, but wouldn't have any idea what it has to do with refacing motorcycle cylinders. Can someone help us out? We have over 15 vintage bikes that are waiting restoration, but we need machinery...Thanks in advance!!

 

[Pig Predator]

What you're looking for is called a bridgeport mill. I would send them off to someone who already has the equipment and experience running it personally.

 

[Dialer]

Not for $145 per cylinder! That's highway robbery!

 

[Pig Predator]

Not for $145 per cylinder! That's highway robbery!

How much is it going to cost you to replace that vintage #'s matching cylinder when you screw it up? I mean, you didn't even know what the machine was called, I'm pretty confident that you or your partner dont know how to run it as well.

As a small business owner myself, that $145 shouldn't cost you a dime and you should have a little peace of mind knowing that a competent machinist performed the bore and honing and will stand by it. But, to each their own.

 

[livinoutdoors]

Not to mention if you think $145 is a bunch then you are gon be shocked when you see the price of machinist equipment. Mills aint cheap.

 

[Doboy Dawg]

You can find used US made machines for twice the price of Chinesium machines. That doesn’t include the schooling to learn how to properly set them up and operate.

How many jugs can you bore for $8000? I have a small milling machine and lathe that i could do motorcycle jugs on.

I take all my jugs and engine blocks to my local machine shop. Their costs get passed on to a customer. More than once they have saved me from using a block, head, or jug that I wouldn’t have found on my own.

I have an old school 350 SBC Chevy block and a 5.3 LS block at their shop now. My machinist called today the heads off the 350 are cracked.

We built a LS motor and replaced the head gaskets that blew again after a few weeks. The heads were cracked. We lost a good bit of money on that motor, but we made it right. Even the pro machinist can’t catch every flaw.

They comped us a LS block and set of heads for missing that. They didn’t have to do that.

 

[earlthegoat2]

$145/cyl for a motorcycle engine (jug) is not bad. They are best done on a lathe or milling machine.

Boring bars, like the above pictured Kwik-way, are really meant to be anchored on cast iron blocks of multiple cylinders for rigidity. Though, I have used one to bore out many Briggs Vanguard engines (aluminum) that folks used to put in their racing garden tractors. Yes, that is really a thing. I also used them for a number of L-head Briggs engines (iron) for junior dragsters. Both of these would have been better done on a machine described below.

Aluminum blocks are best done in a machine that has an adjustable cradle such as is made by Sunnen or Rockler. That is assuming the aluminum block does not need a new sleeve.

Anyway, boring bars are best used for blocks as opposed to jugs. Anything is possible though.

 

[Jim Baker]

Not for $145 per cylinder! That's highway robbery!

What is the % does 300 bucks add to the cost of a restoration.

 

[greg_n_clayton]

All my old Harley stuff goes to Pete Hill in Greenville SC. He has built 1000s of old motors in his time !

 

[NE GA Pappy]

the machine pictured above is what you want for small engine or motorcycle jugs. The heavy plate in the middle of the machine is used to bolt the jug to the underside. Then you center the boring bar over the jug and bore it. The heavy plate keeps everything from warping or moving around.

ps... I owned 2 NAPA stores in a prior life and still have some machine shop equipment, but not a small engine boring bar

 

[gma1320]

If you bought a new Sunnen machine they would probably teach you the basics of using it. You really need someone with a lot of experience to show you how to machine blocks. It is not something you are going to learn. By spending money on the machine and watching videos. Might be a good idea to spend $145, develop a relationship with that machinist over time and then see if he might be willing to teach you how to do it.

 

[Raylander]

Just pay the man

 

[MudDucker]

Back in my youth when I raced motorcycles, I was told a good hone would fix most problems. A buds dad had a milling machine and he said he knew what he was doing. He did, he knew how to make me buy a new cylinder. I would absolutely get it done professionally!