What's the trick to parting the cylinder barrels?

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powerdoc

powerdoc

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So I got the head off without much fanfare (you do really need a 3rd hand to hold those pushrods, though) but I can't part the cylinders from the bottom end cases. I'm pretty sure I've loosened all 9 bolts/studs but I can't part the barrels. I did some gentle tapping with a mallet and screwdriver at the joint of the bottom of the barrels but no go. What's the trick here?
 
Hi Powerdoc,
I think the base nuts should be longer than normal nuts (excuse the innuendo!) by undoing the base nuts they top out against the barrels
and force the barrels up. If you have short nuts, try putting a spacer above the nuts and then undoing them to force the barrels up.
Cheers
Martin
 
First...take a deep breath and tell yourself that you are NOT going to break off a fin. I looked at the idea of backing off the nuts to force upward on the fins but they are too far outboard and will put a lot of stress on the fin. So instead, a poured myself a drink and set up my heat gun to blow on the joint. This took a long time to get hot, so I poured a second drink, found my rawhide mallet and tapped at it sideways. Finally I ran the nuts to the tops of the studs and used that as a fulcrum to lever against. By putting the tip of my lever at the base of the fin, closest to the cylinder wall I figured I would be less likely to break one off. Amazingly by working my way around on the four corners it took very little pressure to start raising the cylinders off the cases.

I don't know if the heat did any good, but it gave me time to have a drink and think about it. I don't know if the drink did any good, but it gave me the courage to proceed. Be careful, and good luck.

Russ
 
No, don't try to force the barrels with the nuts against the fins, they will break. Put the head back on without the rods and try the rubber mallet against the exhaust area or the carb area. Once it breaks loose just keep rocking it and loosen the nuts as it goes up. Have some wood shims you can stick between the cylinder and base. Easy does it, don't break anything.

Dave
69S
 
Dogt's advice is solid.

Another thing to try is spinning over the engine, see if the friction of the ring/pistons make the barrel move.
 
Very easy to remove stuck cylinders: You will need a piece of hardwood about 50x100mm, and a reasonably heavy copper hammer. Hold the hardwood against the top cylinder fins, and hit it quite hard with the copper hammer, working around the cylinder. This method works fine on alloy cylinders fitted to Jap motors, and never had a problem with broken fins.
 
DogT said:
No, don't try to force the barrels with the nuts against the fins, they will break. Put the head back on without the rods and try the rubber mallet against the exhaust area or the carb area. Once it breaks loose just keep rocking it and loosen the nuts as it goes up. Have some wood shims you can stick between the cylinder and base. Easy does it, don't break anything.

Dave
69S
Click to expand...

I like the idea of putting the head back on and going for the most substantial parts of it, the exhaust and the intakes. I've used a heavy hammer with a piece of wood as an intermediary. You only need to use the 4 side bolts and the center nut, tighten them though. A little heat of the propane variety along the base gasket might help if you're going to repaint the cylinders.
 
Presumeing youre tearing the base gasket asunder , the heay gun will be a asist . Fins & Wood == SQUARE to FINS .
With a bolchk or two ( for Sq. Fwd , a 20 in 4 x 2 pine . SOFT will split the joint .Yea , a few little wedges could help
once an edge is pried , if its free fore & aft , both arms on it shoulg go straight up.

If youve a second pair of arms handy , grab the rods before they slap the case , but pistons pushed right down should
prevent the rods nicking & parting compant at redline . :mrgreen:
 
If I'm applying heat, does it go on the base of the barrel or on the aluminium?
 
powerdoc said:
If I'm applying heat, does it go on the base of the barrel or on the aluminium?
Click to expand...

I think it's safe to go along the seam. I was thinking along the lines of spit sizzle temps, noting more. You could do the same thing with a heat gun.
 
In about all cases that don't just give up on first timid efforts, apply HEAT as your shop friend. Do not be afraid of fry pan oil smoke temps if need be. Heat the barrel as easier to hit and holds heat longer than Al. Razor blades helped me get one off that had glue like hard crust in the seam. I've also lifted hard one with rest of bike intact by bolting a bar across top of cylinder with a small block of wood under it then use rear wheel to bump the bugger off its ass. You can pre load the jugs by snugging the long nuts up on fins pretty good, just not enough risking a fin rupture.
 
Right after coffee in the AM the "blue wrench" will come out again! I'll start without the head but if necessary will add same to increase the leverage. I do really hate to beat on potentially fragile aluminium. And I only used to think the castings on the head were bad; once I got it off I can see how REALLY bad they are!

That third bolt in the front of the head was a bugger to remove. A piece of flashing had fallen off and wedged itself next to the head and, until I got out the flashlight to look in there, I wasted about 15 min just poking the socket around trying to get it to catch. Once I pulled that bit of metal out with forceps it was easy to remove the bolt.

I guess it was made on a Friday.
 
powerdoc said:
I wasted about 15 min
Click to expand...
You're lucky. I spent 2 days trying to line up the transmission spline into the clutch housing on a JD2020. I couldn't believe it when it just went in with a clunk. I've had hours on the Norton, just getting the air filter off.

Dave
69S
 
I personally feel that once those things fit together, a liberal retro-lingual application of C2H5OH is always in order!
 
The reason cylinders are sometimes difficult to remove (unless very bad corrosion is present, where heat from a large propane torch is a good idea), is due to the gasket having become very effectively glued to both parts. Using a piece of hardwood to protect the upper cylinder fins and hitting quite hard with a heavy copper hammer, will work in nearly every case. Bad idea to use softwood for this job, as this might well split and allow hammer blow to contact fins directly.
 
Previous experiance with large hammers , mallets or backs of axes is adviseable . Please dont experiment on Injun .

' A Judisious Tap " of adequate proportion intelegently applied tangentally perhaps . The Extra hight of head does provide twice the moment levering . But you must be organised , as far as a stock of suitable timber offcuts go .

In fact cutting of to suitable dimensions is recomended . A 4 x 2 across the top near rear footrest mounts , one at the
rear of cylinder.And a bootle jack would do it . WITH CAUTION . There could be trouble if youve missed a nut or bolt .

Same , a V cut section on Fr Frame rails , , Block , lever , and one on the fins @ front . CAREFULLY . Beer LATER .

I think Id go for the Heat Cycle bit , and persevre with patiance . Anyone with a short temper , take up walking .
 
This all comes under the heading of IMHO. Don't strike the fins, with a hammer or anything else. Heat the area of the gasket because that's what's gluing everything together, it will help soften it. Put the head back on and strike the area of the exhaust or intakes with a hammer, using a block of wood to keep from marring the head.
 
You could actually bolt a block of hardwood on to the top of the barrels using the head studs/bolts. And whack away on it. I really prefer a heat gun to a torch as I don't have to worry too much about it if I clamp it in place and go find something else to do. The patience thing is the key. I found after bringing everything up to temp that it came apart very easily. It might have been luck, but mostly it was a matter of getting it to wiggle and shiming something underneath as I worked it higher.

If you buy a heat gun, get one with as much wattage as you can find. A good one isn't cheap but if you don't go from a high setting to off without a cooling period with the fan on they last nearly forever. I have an old Wagner that I have been using for almost 30 years and it gets used a lot!

Russ
 
DogT, good to know there's another Norton guy who likes tractors. They're both simple machines, really, just the Commando is a bit more eccentric.
 
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