Author Topic: Head gasket leak  (Read 1404 times)

Online muskrat

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Re: Head gasket leak
« Reply #15 on: 03.12. 2014 07:37 »
Still the ? remains. Where is the oil getting in to blow out. The piston is oil crusted, the only way in is from rings or valve/guide. You could deck the head and barrels and use superglue at the joint to seal it but the oil will still make its way to the wrong side of the piston. For a few £ a quick hone and new rings (bed in correctly) will eliminate one possibility. Worn guides/valves can be lived with but loose guides can't. I always use the copper spray on head gaskets (habit from running 14:1 on the racer).
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'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
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Offline Andreas Larsen

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Re: Head gasket leak
« Reply #16 on: 03.12. 2014 09:04 »
Copper spray is sadly not legal i the EU I htink, at least I've trawled the www for it and can only find north american or australian supplies that state they only ship nationally..

Edit: I've found some guides to make your own but I don't know if that is wise?  *eek*
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Offline a101960

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Re: Head gasket leak
« Reply #17 on: 03.12. 2014 09:56 »
Quote
Copper spray is sadly not legal i the EU I htink, at least I've trawled the www for it and can only find north american or australian supplies that state they only ship nationally..
Available in the UK from: http://www.ebay.co.uk/itm/VHT-SP21A-COPPER-GASKET-CEMENT-CORK-PAPER-METAL-GASKETS-/380614635400?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item589e666f88 I bought some from this place. They do ship to addresses outside the UK, but check by emailing here  ebay@partsorama.com for shipping cost because it can only be shipped via a courier. They cannot send via post.
John

Online Rocket Racer

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Re: Head gasket leak
« Reply #18 on: 03.01. 2015 22:44 »
A mates '55 flash showed some evidence of a weeping head gasket so we lifted the head on New Years day. Both the front oil drains showed blow out and that was only enough to wet the fins, not leak back beyond the barrel. So not the same as your problem

It'll go back on with some copper spray on the annealed gasket, once the valves go back in.
Exhaust clearances were tight and the exhaust valves both leaking and corroded on the seat, one quite badly. Not wishing to highjack the thread, all the valves are just outside clearance but as the owner has only just bought the bike I think a bit more bonding/riding time over the summer is in order before the head gets refreshed properly. I found a decent spare exhaust valve to replace the pitted one and all the seats have lapped in nicely with a fine paste, Certainly plenty of clearances presently.

My FIL's Benelli twin had a bad oiling problem out an exhaust and it turned out to be a failed guide, the bottom half of the guide had broken up and vanished. So oil was getting down the guide remnant and that cylinder didnt run reliably, kept chiming in but not at idle.
A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
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