The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: ColinF on 24.10. 2016 19:12

Title: What goes there?
Post by: ColinF on 24.10. 2016 19:12
Hi, i'm currently building a custom bike based on a 1953 A10 plunger frame and engine for a friend.The whole thing turned up dismantled and in boxes.There are two sets of crankcases, the set with matching numbers to the log book and a second set which had the crank in it.I know the cases are stamped in pairs and assume this means they were align bored at the factory and aren't interchangeable? The original set has a hole in the back of the primary case above the sprocket and the 2nd set has damage where the dynamo mounts. I would rather use the original set to keep the engine number, i know i can get the hole repaired too. There is a flange on the back of the primary cover part of the left hand crankcase,above the drive sprocket,what is mounted on this? It has a small hole in it at the front and a threaded hole at the back.This flange is damaged ,probably by the chain, I was thinking of trimming it back before getting the repair done but need to know if i still need a mounting point there. Any help would be appreciated.
P.S can post pic if it helps.
Title: Re: What goes there?
Post by: chaterlea25 on 24.10. 2016 19:47
P.S can post pic if it helps.

Please do

Title: Re: What goes there?
Post by: morris on 24.10. 2016 22:02
Hi Colin, I understand you're referring to the flange on the left of the drawing at the back of the chaincase.
The small hole is for a bracket that holds the breather pipe above the chain. There's a drop of oil coming out of the breather from time to time which otherwise would be wasted but then serves as an automatic chain oiler.  *smile*
The bigger threaded hole is for the chainguard.
I'm not using any of them. I pushed a rubber hose on the breather and let the odd drop just fall down.
The threaded hole is for the chainguard, but is not really necessary either.
The chaincase will easily hold on the mudguard and rear chaincase bracket.
Title: Re: What goes there?
Post by: ColinF on 26.10. 2016 20:44
Hi, thanks for the replies.Can't post pic of actual part as my nephew has taken it to work ( large engineering company that reconditions engines ) for their alloy welder to look at but the illustration posted above shows the flange in question. I was hoping it wasn't really needed so it can be neatly cut back .The custom bike wont be using the standard chain guard anyway.Once the repair is done i can get on with rebuilding the engine.I'll probably be back to find out the best places for engine parts as it's unlikely it's all there!
Thanks again,Colin.