Atlas Jugs Cracked

britbikemike

Joined
Aug 2, 2011
Messages
162
I am full head on into the Atlas restore now. I have grease in places I didn't know I could get grease! lol Most of my chrome is pitted, and would be better suited for sandblasting and a good powder coat, so it is probably going to get a mild period custom look. However I had a devil of a time getting the jugs off. One of them was cracked all the way through on the lower flange. Anyone else ever seen this? I took it, and the one for the Commando, into the shop and they said it could probably be repaired???? Anyone ever heard of this? Should I be worried? The jugs had not been bored, but I am a little concerned about just how they are going to go about doing it.
 
They would probably put new liners in and ignore the cracks or remove the cracked portion. Once you factor in the cost of the liners, fitting then reboring to accept new pistons I think you would be better off with a good used barrell.
 
Perhaps you should ask them how they are going to repair it ? !!

If done with new steel sleeves, it could well be better than new.
Certainly those iron flanges are often seen with damage.
 
750 Norton jugs are all over Ebay like dog-shit and they are cheap. It would be easy to find a set that is std. waiting for a first oversize. This would be cheaper and more reliable than a set of cylinders with some hokey repair job on them. Unless you are dealing with ultra-rare cylinders, like pre-war, model 88 or cammy parts, then it is not worth doing anything than just replacing them....
 
Re: Atlas Jugs Cracked-UPADATE

I finally got the estimate back on the Atlas jugs. They were cracked in THREE places! This guy owned a Triumph shop in the 60's, and used to race Nortons at Daytona. He STILL builds race engines for the old bikes, so I am very confident in his work. He will re-sleeve the cylinders and bore them out to standard, and evidently get the three layers of paint off of it (lol) for $300. To me that seems like a pretty good deal. Any thoughts on that? Any one else ever had this done? The last few sets of jugs I have seen on Ebay have gone for that or more with shipping, and they would probably still have to be honed at least. I guess I am jsut looking for some feedback.
 
Why not go for it ? If you buy some jugs off of e-bay there's the possibility of something being wrong with it, that even the seller was not aware of. Also your helping to keep this guy in business. I have some cylinders that broken at the bottom and i was thinking that they were done, maybe i'll send them to this guy to have a look at. I'll be curious how yours turn out. Cj
 
I used to have a 1965 Atlas that gave me numerous problems, and one was where all the studs holding the barrel into the crankcase came loose on the motorway on a dark night allowing the barrel to go up and down with the pistons then when I pulled over to the hard shoulder the engine locked up as the barrel tipped over. Part of the bottom flange on the barrel was cracked/broken, and I took it into a professional welded who could weld anything from alloy to cast iron as he had a TIG welder and he did a good job as I was able to reuse the barrel.
So, It probably could be done.
 
Bernhard said:
I used to have a 1965 Atlas that gave me numerous problems, and one was where all the studs holding the barrel into the crankcase came loose on the motorway on a dark night allowing the barrel to go up and down with the pistons then when I pulled over to the hard shoulder the engine locked up as the barrel tipped over. Part of the bottom flange on the barrel was cracked/broken, and I took it into a professional welded who could weld anything from alloy to cast iron as he had a TIG welder and he did a good job as I was able to reuse the barrel.
So, It probably could be done.
Click to expand...

Were you living near Heathrow?
I had an Atlas with a repair to the barrel flange.
 
[Were you living near Heathrow?
I had an Atlas with a repair to the barrel flange.[/quote]

Yep, at the time that I owned the Atlas. This is too much of a coincidence, which year did you weld up an Atlas barrel base flange? or did you buy a Atlas from Heathrow with this repair?
 
Here is the work the guy did on the jugs. Not too shabby at all.

Atlas Jugs Cracked
 
He put in new sleeves and set them back to standard. On the other side you can see a small hole where he did a small weld to secure them. Then he honed the new pistons to each cylinder.
 
Now you have a shiny barrel with a dangerously weak bottom flange - might hold up for a round around the block but useless for serious and fast riding. I have several cracked barrels here in my workshop that were once repaired with liners. The remaining material at the milled flats where the bolts sit is in places less than 1mm thick - no wonder they cracked (and destroyed the whole engine at 6000 revs...)

Good luck
 
WEAL Norton said:
The remaining material at the milled flats where the bolts sit is in places less than 1mm thick
Click to expand...

What does this statement actually mean.
What milled flats, what bolts ?

Hepolite have long supplied new sleeves to solve worn out cylinders, spun cast is the description usually applied to them. If they were not suitable for the job, you'd imagine that Hepolite would not have supplied them ? Sleeving is very common in the automotive world.
More detail required...
 
The automotive world is very different than what is used on the Norton. The Norton 750 cylinders are held to the crankcase with the flange, sleeving the cylinder removes the very metal holding the flange to the rest of the cylinder. I guess with through bolts, sleeving could be considered, but as WEAL norton mentionned the flange could break off and destroy the engine if the stock fasteners are used.

Jean
 
Triuph :shock: :oops: SLEEVEs are not uncommon , though lipped at top to locate vertically .
Some cowboys use Bonneville Sleeves & Pistons in Tridents .
The Alloy T100 & Dunstall 810 use them for some reason . :D

Useing a THIN paper gasket & considerate tightening ( EVENLY & PROGRESSIVELY ) should see it right .
Dont use a 5 yard thick cardboad gasket though.

Running Loose , as stated , can lead to later poroblems . perhaps .

Triumph :shock: :oops: Twins Blew the Barrels if Drag Raced on fuel , AT .060 over . But blew the
contraption apart ABOVE the flange . :D Suppose thats where your refering to it being a trifle thin .

Out with the Ruler . :p :? .
 
This repaired cylinder is pretty likely to either fail in use (bottom spigot broken off), or after a while will result in quite a lot of noise, as the unsupported part of the liner will heat up a lot quicker than the rest, and the resulting expansion may well be enough to nip the skirt of the piston.

Maybe a good idea to advertise the whole lot on Ebay, and look for a good used cylinder that can be relied on for trouble free service in future?
 
Carbonfibre said:
, as the unsupported part of the liner will heat up a lot quicker than the rest, and the resulting expansion may well be enough to nip the skirt of the piston.
Click to expand...

The laws of physics say that cylinder sleeves never expand inwards, so this comment is nonsense. And why sleeving is a common automotive practice. The bottom of the sleeve/spiggot gets almost no loading and almost no heat, so its not as though they are mission critical or anything.

Triumph used very thin sleeves extending to the spiggot in their alloy cylinders even from the early 50s, and providing they weren't mishandled are still around today.

Cheers.
 
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