The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: Housewiz on 03.12. 2012 22:23
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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
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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.
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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
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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
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But i've always used a tyre lever between the bottom two fins and heaved...... So that's why i always brake fins?
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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
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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? *smile*)
good luck ,duTch
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That's not a bad idea at all Dutch. How about eye bolts into the head bolt holes and a winch from the rafters. *eek*
Cheers
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Hey Dutch,
Excellent idea. Will have a go and report the results.
Thanks,
Steve
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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 !!
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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 *lol*............ There's always a way! wink2
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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
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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.
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And make sure it's on the compression stroke. Don't want to bend valves too. *eek*
Cheers
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A mate of mine used the rope in the combustion chamber trick, to replace a valve spring or something related. Seems to work!
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Yes I too use the Indian Rope Trick.
Back off the rockers slip some good rope ( hemp is best ) down the plug holes then either a couple of swift kicks or a bit of a walk down hill in top.
Never fails
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Glad it worked Steve, I came on that idea by misdemeanor long time gone, where bodgy nuts had locked onto too-long studs, and the only way out was up, so was born a not so useless idea>>!
Hey muskie that' a great idea too, you must have some very rare BSF eye bolts ;), best I can come up with is Eye nuts on a mixed thread stud (....?/BSF), trouble is I've only found metric series eye nuts(maybe I shop at the wrong places), and I dunno that a imperial/metric combo exists, without custom engineering....... *smile*..... and then yea'd need to maybe bolt bottom end to the floor, if it's really well glued on....and if your little winch doesn't work, I have access to some small heavy lift cranage (or is it 'carnage'), 500T..? *eek*
No worries Bob, the brain cells need a shake up every now and then, they get complacent and lazy, nothin' better than a bit of random shock therapy *conf*
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That's not a bad idea at all Dutch. How about eye bolts into the head bolt holes and a winch from the rafters. *eek*
Cheers
Why don't you tell everbody what happened when you last used that method Muskrat?........... Better still. I will show them!
https://www.youtube.com/watch?v=Ylinj9Jc9WM
10/10 for effort.... but honestly!!! *doh*
No offence meant Mate, it's not a bad idea at a pinch!
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Ah, maybe that's why I now roll out of bed at night. The rafters in the shed are the floor joists for the bedroom. *smile*
Living in the bush for years with no electricity, I had to invent ways of doing lots of things. I built the racer at night with a kero lantern for light. *eek*
Cheers
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Hoo boy, yup I've seen that a few times, I think I worked with someone a while back who was there- bad blue!
Musky, at least I had the luxury of a 2KVa gen-set, Lister powered, 3-1/2 HP single, still got it, but a bit weather beaten, was it a lantern, or an 'Aladdin'- you know the pressure ones with metho starter and then pump it up - that's what I grew up with....till we got a 32 V Southern Cross powered setup, them wuz the daze.. *conf*
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Trying to get the rotor nut off a Bantam at the weekend I couldn't get things to lock up sufficiently - clutch seemed to slip. I ended up lobbing a small block of wood in the hole and bolting the head back on. That seemed to do it.
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Don't forget to take the wood out, I know it burns, but at a guess I'd say the octane rating is low..but there could be room for a steam boiler- just add water ?