BSA Owners' Club Workshop Discussions

The BSA Workshop => Twins => Topic started by: AdrianS on 05 Sep, 2020, 18:34

Title: A50 head gasket
Post by: AdrianS on 05 Sep, 2020, 18:34
In preparation for my engine strip, I will need a new head gasket. I believe the early engines had a composite gasket and later ones had a solid copper gasket which could be re annealed.
Can either gasket be used? I haven't a clue what is on the engine at the mo, but with oil weeping out of the head joint somewhere I suspect it is a composite gasket.
Title: Re: A50 head gasket
Post by: Bess on 05 Sep, 2020, 19:32
Hi,
    You can use both, however:

I would use a solid gasket along with new bolts and the recommended thicker washers all purchased from SRM in Wales for the best result.

Best wishes...
Title: Re: A50 head gasket
Post by: AdrianS on 05 Sep, 2020, 20:59
Cheers
Will be in touch with SRM!
Title: Re: A50 head gasket
Post by: DAVE BRADY on 05 Sep, 2020, 22:03
Adrian,

If you haven't already got one get a tap to clean the threads in the barrels.  It is surprising how much muck is down there and the resistance it creates absorbs effort so reducing the accuracy of the torque setting.  SRM may supply one.

Dave.
Title: Re: A50 head gasket
Post by: JulianS on 06 Sep, 2020, 09:47
The later models had the 2 rear head bolts, orignally 5/16 inch diameter, increased to 3/8 inch to improve sealing.

BSA issued a service bulletin detailing converting earlier models.

Worth considering if you still have 5/16 rear bolts.
Title: Re: A50 head gasket
Post by: Mike Farmer on 06 Sep, 2020, 16:49
 :) :) :)

I did this mod on A65. Its worth noting at this stage that you will also need the rear head bolt holes drilled out. If they are not dead square then you will have serious problem. I know cos---------------and it wasn't me that drilled it.

Mike 8) 8) 8) 8)