Preferred method for barrel removal

[Housewiz]

Popped off the head today and was moving towards pulling the barrel.  Rapped the edges of the fins with a rubber and leather mallets a few times and with all the broken fins I have (PO - not me!) on the head and barrel I stopped.  Not interested in driving a sharp edged pry between the barrel and lower end casing so I am looking for recommendations from those of you who have completed a successful separation of the parties in question.

Thanks,

Steve

[Brian]

They should come off reasonably easily Steve. Give them a tap with your rubber mallet from a few different directions, eg. from the side front rear etc. The thing to remember when using a mallet is to only hit them directly on the end of the fins, never up or down as that is what will break the fins.

After you have tapped them a few times push the pistons down the bore and grab hold of the barrel from the top and give them a good wiggle and pull upwards, they should come off easily.

[Housewiz]

Hey Brian,

Did all that - precisely as you stated.  Nada as we say in the US.  Will have another go tomorrow.  I want to sell these puppies, even w/minor fin damage so I am being ultra careful.  Due to really high repair estimates, I had to buy a new thick barrel and alloy (2 carb) head.  Splurge I guess on the dually however I really wanted a unique SR that sports two blingy 279 Amals.

Thanks,

Steve

[mark]

I had a similar problem where the barrel wouldn't budge. I found that there was a small overhang between the flange and crankcase at the rear left side and used a screwdriver that was long enough to be able to be hit from below the engine plates. A couple of sharp taps was enough to break the seal.

Regards
Mark

[wilko]

But i've always used a tyre lever between the bottom two fins and heaved...... So that's why i always brake fins?

[muskrat]

 I use a 18" jemmy bar placed under the bottom fin and right in against the body, a piece of wood on the timing or primary covers. I need to do this way as the cylinder studs go right through the barrels and head.
Cheers

[duTch]

 I'm not sure if I've actually had to do it, but how about a piece of flat bar or similar between the bottom fin and the flange nuts, and as you undo the nuts, in turn will push the barrel (carefully), they're a fine thread, so good mechanical advantage. may need to be in conjunction with the 'Light Tap' (Hey I mentioned rubber mallet a while back and copped shit- so hey yeah?  )
 good luck ,duTch

[muskrat]

 That's not a bad idea at all Dutch. How about eye bolts into the head bolt holes and a winch from the rafters.
Cheers

[Housewiz]

Hey Dutch,

Excellent idea.  Will have a go and report the results. 

Thanks,

Steve

[Topdad]

Dutch , thats a great idea next time I'll try that, Musky sounds a bit bit ott but... we are talking cantankerous old BSA's here so anything considered, cheers BobH ps doing that arseover obviously didn't do any  damage to the brainbox then Dutch !!

[metalflake11]

Great idea Dutch! ...........I've got some 750 Bonnie barrells that wont come off, I'm going to try that. If it fails, it's out with the block and tackle and try Muskrats plan ............ There's always a way! wink2

[Housewiz]

Hey Dutch,

Your idea worked perfectly.  Barrels are off.  One .040 piston and rings are a bit rusty - maybe the PO left out that spark plug?

Crank spins nice.  Time for a rebuild along with a valve job on the head.  Odd the pushrods were missing.

Thanks again!!

Steve

[NottsIan]

Glad you got the barrels off.

For future reference, here's another technique I've used before.

Put the head back on. With the pistons near the bottom, feed some soft rope into the plugholes so it coils up on top of the pistons. Turn the engine over gently, the pistons will push the barrels off. This also works for getting stuck cylinder heads off too (with the head bolts out of course!)

Hope it helps someone.

Ian.

[muskrat]

And make sure it's on the compression stroke. Don't want to bend valves too.
Cheers

[metalflake11]

A mate of mine used the rope in the combustion chamber trick, to replace a valve spring or something related. Seems to work!