cracker Barrel

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E

ernest

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Oct 14, 2009
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I've managed to knock over my cylinder barrel and have it land on the worst place.

Here's a pic of the cylinder flange showing the crack right along base.
cracker Barrel


Inside the cylinder hairline crack.
cracker Barrel


Is this barrel now scrap metal?
 
No it's not just need to hunt down L.A. sleeve. And a machine shop who has done this job on a Brit Bike. Be sure they do know British iron though. Tough break.
 
thanks, I think I've got local shop where I was going to have the valves done that should be able to put in a new sleeve.
I don't imagine British bikes are worked on there all that often but they did the work on a friends Commando a few years ago and he's still running fine.

If you think I should have all this done by a specialist then let me know. I've got a quote from Leo Goff of Memphis Motor Works for the valve work but if he can manage all this...I'm in this deep anyways and may want to just bite the bullet and have the piece of mind it was done correctly. If this is all pretty standard though, I'm fine saving a few bucks.
 
Well when the jobs all done you don't need excuses. You don’t want the spigot so thin at the bottom that it has no strength for the job it must do. Conversely you don’t want the liner so thick that it can be seen through the base of the fins. When they do the cut out for clearing the connecting rods you will need to see a radius in the corners of the cuts just like on your jug not a sharp 90 degree corner. How big of a lip at the top of the liner? Heat the jug and chill the liner? Hold it down in the press firmly till it’s all cooled down? How much piston clearance for the pistons? And what grit hone for your rings is right? At least get a quote from a known good Brit bike guy like: http://www.evengineering.com/ before you go saving a buck. Just so you know how much money you saved doing it what other way you feel you need to.
 
Send it to Leo. It's a lot cheaper then going to a hammer machinist. Pay Leo first, then you don't have to pay the hammer machinist. Ask me how I know this.
 
Being a 750 barrel it @#$%ed really, it will become very weak at the flange, now I know some of you will cry that you have been sleeving 750 barrels for years and that they have sat on your bike for 25 year in the garage and never broke......
 
So your going to s%$*t and get without fleshing out your reasoning? So, more than one experience with this? Was it done by someone who had at least done one before? Now if someone had a good jug excess to their needs for the right price why not just go that way. But last I heard they are not all over the place.
 
By the time you bore the barrel for the sleeve the join at the flange gets very thin =weak,850 type barrels get away with it because the through bolt clamp from the top and not just around the bottom.That said if you fitted 7.1 com pistons and putted about like nanna ....
 
Interesting, I have never heard of this happening to any one. But if you say so, must be true. I am sure you’re not just supposing. Must have seen it happen. I wonder if you know if anyone has tried to machine a set of 750 jugs into a through bolt set up at the same time making the fix a good one.
 
splatt said:
That said if you fitted 7.1 com pistons and putted about like nanna ....
Click to expand...

My limited understanding is that you remove the existing sleeve and put a new one in. When you say the flange will get thin, where and why? Yes, you can talk to me like I don't know what I'm talking about. :mrgreen:

Superior Sleeve here in the Portland area would be more than qualified.

http://www.superiorsleeve.com/

I'm sure he's seen more than his share of Nortons, I'm sure Kenny even sent his share over.

But if Leo Geoff is slated to do some work, I'd just ask him.
 
Dave, The existing sleeve is cast right in the jug so it's not a sleeve just an extension of the casting. When you bore for a healthy sleeve thickness the necessary new hole could raze cane with the strength of the casting on a 750 because of the fault like it makes near the place were the lower flange has to be very strong. Just pushing in a new sleeve doesn't restore that strength. That said if you switched to a through bolt system it may be a mute point.
 
norbsa48503 said:
Dave, The existing sleeve is cast right in the jug so it's not a sleeve just an extension of the casting. When you bore for a healthy sleeve thickness the necessary new hole could raze cane with the strength of the casting on a 750 because of the fault like it makes near the place were the lower flange has to be very strong. Just pushing in a new sleeve doesn't restore that strength. That said if you switched to a through bolt system it may be a mute point.
Click to expand...

Thank you. That makes sense. Stupid question number two. If you broke off the cracked part and smoothed it out would it work? Does the piston go down that far and what stresses would the cylinder see there?
 
The piston has a cut out that is a near miss to the crank. The extension on the casting is needed at bottom dead center. The piston must be supported while the crank makes that pass and the piston changes direction. A lot of near misses down in there and the change in directions are not gentle.
 
Ernest,
check w/ GrandPaul for a spare jug.
He has just about every extra part you could ask for.
A board member sale may save you some $.
I'm just not sure money wise how the jug cost sizes up to the price of repairing your
current one? A price comparison there will determine if its worth replacing or repairing.
Marshal
 
PM replied to.

My one and only spare set of jugs have cracked/missing sleeves and are near max overbore.

Equal headache levels.

I'd leave it to Leo Goff.
 
thanks, I'll hear back from Leo to see if he'll take it. Unless something on ebay pops up or anyone else reading has a jug they'll sell I'll just have to ride with a sleeved cylinder.
 
Re: cracker Barrel
by splatt » Sat May 08, 2010 2:12 pm

Being a 750 barrel it @#$%ed really, it will become very weak at the flange, now I know some of you will cry that you have been sleeving 750 barrels for years and that they have sat on your bike for 25 year in the garage and never broke......



I totally agree with Splatt . A 750 barell is useless for sleeving if it is going to be used in anger . Even an 850 barell will show daylight when bored to 920 but this has enough meat to survive A 750 barell hasn,t got the material above the base flange
So .....it is scrap
If you are going to sleeve anyway please let us know after howmany miles the barrel started to go up and down with the pistons .And yes Norbsa I have seen this happen .
 
My bet is this problem could be over come with some extra machining. You would procure a sleeve from L.A. Sleeve the same O.D. as the cast extensions on the jug as a starting point. That sleeve would only be left that O.D. at the exposed bottom. Say 4” longer than needed fer holding in the lathe. It would than be reduced in the lathe to a working wall thickness for the rest of its diameter. A thread would than be cut both in the cylinder wall at the top and onto the sleeve at the top eliminating the need for a spigot at the top of the liner. Just one inch of fine thread would do. With modern high temp thread locking compounds it would be very stout. This has been done before as a way to manufacture liners in the past.
Of course buying a set of the 750 through bolt castings would be even better. And again has anyone tried re-drilling the old casting for this through bolt set up? Just what I need another project.
 
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