68 barrel spigot cracks. Can it be saved?

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The repair is pretty involved.
It can be welded [nickle, silver or bronze] with a pre and post heat of 1500 degrees plus.

Sleeved 750 barrels often crack near the base bolts as they are very thin after installing sleeves.

I have seen a lot of barrels run with cracks. It makes the engine a little noisier. Jim
 
comnoz said:
The repair is pretty involved.
It can be welded [nickle, silver or bronze] with a pre and post heat of 1500 degrees plus.

Sleeved 750 barrels often crack near the base bolts as they are very thin after installing sleeves.

I have seen a lot of barrels run with cracks. It makes the engine a little noisier. Jim
Click to expand...

So basically what I hear you say is he should live with what he has (run it), and repairs and/or sleeving is not a viable solution.

To add to your implication, many bikes run with the portion that is cracked totally removed. Yes/no? And if so, wouldn't it advisable to go ahead and remove the portion that may potentially releave itself while running.

If I recall, this is not all that uncommon. Yes/no?
 
pete.v said:
comnoz said:
The repair is pretty involved.
It can be welded [nickle, silver or bronze] with a pre and post heat of 1500 degrees plus.

Sleeved 750 barrels often crack near the base bolts as they are very thin after installing sleeves.

I have seen a lot of barrels run with cracks. It makes the engine a little noisier. Jim
Click to expand...

So basically what I hear you say is he should live with what he has (run it), and repairs and/or sleeving is not a viable solution.

To add to your implication, many bikes run with the portion that is cracked totally removed. Yes/no? And if so, wouldn't it advisable to go ahead and remove the portion that may potentially releave itself while running.

If I recall, this is not all that uncommon. Yes/no?
Click to expand...

It's not that uncommon.
I would grind out the crack if it is short or break away the piece if it is large. If your missing a large piece all the way to the base of the barrel but just on one side it will run but it will wear a bit faster on the piston skirt. Round off the edges a bit.

If both sides are broken I don't think I would run it, but I have seen it done. Jim
 
Not trying to hijack the thread but since it's the same subject. Could this barrel be used as is? Would be in a street bike, not ridden aggressively.
68 barrel spigot cracks. Can it be saved?
 
I would be happy to run it like that, round the edge off a bit though. I'd feel happier about running it with the piece missing altogether like that than with a crack.
 
Was thinking the same thing. Remove the broken piece and clean it up. Thing is by the time I radius it it will be about 2" long that's about 1/4 of the spigot removed. As It needs a rebore I'm thinking it's worth putting that money toward a new barrel and have piece of mind... Well as much as you can with a commando.

Next thing is what barrel to go for. I see both Norvil and Andover both list new barrels but norvil do list one with thru bolts same as 850. Any thoughts?

Thanks
 
I've been running a through-bolt 750 barrel on my Combat for the last fifteen years or so--it is a very rigid assembly. If you go that route don't forget to reinforce the corresponding crankcase threads with Helicoils or some other insert



Tim Kraakevik
kraakevik@voyager.net
 
htown16 said:
Not trying to hijack the thread but since it's the same subject. Could this barrel be used as is? Would be in a street bike, not ridden aggressively.
68 barrel spigot cracks. Can it be saved?
Click to expand...

You can run it if you round the edges off. It will be a little noisier and it will wear the piston skirt faster.

If it were mine I would give it to someone with a show-more-than-go-bike and find a used barrel to recondition. Jim
 
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