BSA Owners' Club Workshop Discussions

The BSA Workshop => Twins => Topic started by: Caulky on 26 May, 2018, 20:12

Title: '71 A65L Head gasket
Post by: Caulky on 26 May, 2018, 20:12
Hi all
Anyone know where I can buy a 'thick' 2mm? copper head gasket for my lightning?
Title: Re: '71 A65L Head gasket
Post by: AWJDThumper on 27 May, 2018, 08:32
Why do you need such a thick gasket?
Title: Re: '71 A65L Head gasket
Post by: Caulky on 27 May, 2018, 10:45
Because the head has been skimmed and the exhaust pushrods cannot be fitted.
Title: Re: '71 A65L Head gasket
Post by: Bess on 27 May, 2018, 11:00
Hi,
    How deep have the valve seats been ground in the past? is it worth trying a thicker gasket at the base of the cylinder?

Best wishes...
Title: Re: '71 A65L Head gasket
Post by: Caulky on 27 May, 2018, 11:10
I sent the head to "the cylinderheadshop", for new (ethanol) seats, valves and porting.
Not too keen on raising the barrels.
Bonding two copper gaskets together is an option.
Title: Re: '71 A65L Head gasket
Post by: AWJDThumper on 27 May, 2018, 12:55
The neatest solution would be to remove the steel end caps from the pushrods and skim off the required amount and then replace.
Title: Re: '71 A65L Head gasket
Post by: Caulky on 27 May, 2018, 13:48
Thankyou, didn't think of that.
Are the caps just an interference fit?
Title: Re: '71 A65L Head gasket
Post by: AWJDThumper on 27 May, 2018, 14:43
Yes. A bit of gentle heat will expand them and they should then come off.
Title: Re: '71 A65L Head gasket
Post by: Caulky on 27 May, 2018, 14:58
Thanks! I have had the cups come loose, on a Bonnie.
In the meantime I have contacted "Gaskets-to-go" who can make special gaskets.
I`ll post what happens.
I could buy two, one for anyone else in a similar predicament.