Bsa Alternator, Crankshaft type.

[muskrat]

 So if the A7 barrels have been bored out to take 71mm bonny slugs they wouldn't be strong enough to hold a fart let alone decent cr. Sleeve it back and std A7 pistons with the extra stroke will give a decent cr result. To play around with the cr use different thickness head gaskets. Lani at copper gaskets can make them in any thickness and bore size. http://www.coppergaskets.us/MCG.html
Cheers

[Harryc208]

Thats a point I hadn't even thought about, Il have them sleeved.

On the point of strength, In one post didn't you mention a through bolting system? Would that be applicable here?

[muskrat]

If I tell you I'll have to kill you !
Depends on if you want to race it. I was running 13:1 cr on methanol. After breaking a few barrels I worked out the through bolt system. Then it broke a couple of small journal A7 cranks (no large journal for A7). Just moved the weakest link. Hence the idea of the A65 crank. Stopped racing so shelved the crank. I still use the through bolt on the '51 and '57 cafe because I can 
 Keep yours at 9 or less and should be OK.
Cheers
 PS, once done for through bolting the head and barrels are that way for life, the cases can revert to std.

[Harryc208]

I wont be racing, and 13:1 on the fuel we have here would send most engines to mars.

Il try and have barrels sleaved soon, in the meanwhile il have a look at a sleave for the drive side bearing.

[muskrat]

I was telling a friend (poor bugga has only 12 bikes, 1 is a ABSAF 600 Goldie) and he thinks the late B33 alternator covers will fit, or made to.
Cheers

[Harryc208]

After contacting ABSAF, been quoted € 495,00 plus vat for a set of primary cases unpolished.

A little out of my price range, so I think il end up making my own.

[Flatboy 1950]

Hi , I have a set of Alternator chain cases for a twin , but I am in South Africa & the postage usually kills any deal !!

Regards , Flatboy.

[Harryc208]

You have PM flatboy!