A10 Piston Needed for 1953 BB32 Gold Star

[rolfdh9]

I hope someone can help.
I need a Plus 60 A10 piston.
I would prefer 8.5:1 compression ratio but really anything will do.
I have a 1953 BB32 Gold Star engine. It is impossible to get a piston. The bore is 71mm and the barrel is on standard size but needs a rebore. A +60 A10 piston will be about 71.5mm the same as a +20 BB32 piston.
The distance of the top land above the gudgeon pin of the A10 piston is only 1mm more that of a BB32 piston. Apparently according the Auto Cycle this substitution has been done before.
Pairs of pistons cost about £260. I have seen some old original pistons but they are never +60 or they are very well worn.

So please has anyone got a +60 A10 piston they are willing to sell?

[a10rgs]

Hi,
have you tried Mikes Classic Spares in Australia? He has a Std. BB32 piston for sale.
Maybe he can help with an oversize one.
Uwe

[Tors]

i found these

https://www.vintage-motorcycle.com/en/parts/bsa-pistons-new/bsa-a10-piston-060-pair


edit.. sorry you're not looking for a pair..

here's one: https://www.vintage-motorcycle.com/en/parts/bsa-pistons-used/piston-used-60-bsa-a10-racing?destination=/en/search%3Ffulltext%3DA10%2Bpiston

[chaterlea25]

Hi Rolf,
I'm pretty sure I have one, but it is a 10:1
If I get a chance tomorrow I will dig it out and check the size etc.
I had it on our autojumble table and John Harding (piston man) said what it was
that was several years ago so working from memory

John

[chaterlea25]

Hi Rolf,
Attached are photos of the piston I have, it has never been used but has a little oxidation that will clean off easily
I hope the dimensions are readable for you
I do not know why the photo's come out upside down 

John

[bikerjohndavies]

I have a +0.060 9:1 AE piston (11412) spare if you are still looking. Been sat in my spares box for many years but should clean up OK. Where are you?

[rocker21]

many years ago i fitted an A10 piston into a B31 but it needed a spacer under the barrel as the piston hit the head, made it out of a bit of sheet alloy i had and it ran just fine, it was a 9:1 and we went to a rally in Holland on it, ran just fine. i will look and see if i have any A10 pistons in the odds and sods box.

[rolfdh9]

Thank you everyone for you help.
The problem has been solved.
Today I went to the auto jumble at Shepton Mallet in Somerset looking for a piston.
I looked around all of the halls several times. I went back into the main hall for the forth time when I spied a piston which looked interesting. No rings or pin but in good condition. The stall holder said it was BSA A10 +60 oversize. I could not believe it! I bought it straight away and then the stall holder told me that he was John Davies and he had seen my forum posting and brought the piston along incase I turned up at the show. Incredible! I always thought I was mad to keep on wandering around but it paid off.
Thank you John, thank you very much indeed.

[rocker21]

I had a stall at shepton as well, was in the bottom hall

[Radlan2]

I am a Shepton regular as well, I picked up a pre ordered K2F from Paul of APL magnetos. Wish I had known you guys were there so I could have put names to faces. There was a chap outside who campaigns an A10 in a classic scrambler series (have a llook at the amazing Triumph of BNH racing). Anyway the A10 guy has had trouble with barrels breaking at the flange, 3 last year, I told him about my through bolted motor but forgot to say about knocking in a wedge of wood between the rocker box and frame which I read about on the forum!
         About Rolf's piston, I have a '53 BB32 with a scruffy standard piston and also I have a new replacement from an earlier model, part number 65-794. This earlier piston looks the same but with a longer skirt, which can be shortened easily, and also flywheel scalops will need to be added which could be done with hand tools at a pinch.
       Hope this helps
                Chris

[bikerjohndavies]

Thank you John, thank you very much indeed.

Glad I could help and good to chat to you yesterday.