model 20 us export pistons
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- Joined: Fri Aug 03, 2007 4:02 pm
- Location: merseyside UK
model 20 us export pistons
I've just bought a 1955 U.S export model 20 engine. I can see why the fella wanted to sell it because it was minus the pistons and they are proving hard to find. The cylinders are bored out to a 545cc capacity (69mm). Can anyone point the way to a pair?
john cavanagh
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model 20 us export pistons
If you look at the engine stamping see if it is: 55/20B. The G9B/20B were the factory 545cc varient made especially for Cooper Motors, the West Coast distributor. All twins shipped to our West Coast in 1954 & 1955 appear to be the "B" varient.
I am often asked for a source of pistons & have asked the few specialists on these motors but know of none, although they do turn up occasionally.
I suggest you bite the bullet & have some made up. JP Pistons will likely make them for you & if you buy a minimum quantitiy of assorted sizes, probably get a reasonable quote.
Post a inquiry on this forum & the Yahoo! also as there are more over here. Also send a quiry to the North American Section Secretary, (John Deiderich, cycletoys@aol.com), & ask for it to be placed in our newsletter.
Cheers, Don.
I am often asked for a source of pistons & have asked the few specialists on these motors but know of none, although they do turn up occasionally.
I suggest you bite the bullet & have some made up. JP Pistons will likely make them for you & if you buy a minimum quantitiy of assorted sizes, probably get a reasonable quote.
Post a inquiry on this forum & the Yahoo! also as there are more over here. Also send a quiry to the North American Section Secretary, (John Deiderich, cycletoys@aol.com), & ask for it to be placed in our newsletter.
Cheers, Don.
- GSAX1
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model 20 us export pistons
I saw two new ones at a jumble some month ago. Didn't buy them because I didn't think they were worth anything.
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- Joined: Fri Aug 03, 2007 4:02 pm
- Location: merseyside UK
model 20 us export pistons
john cavanagh
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- Posts: 3
- Joined: Fri Aug 03, 2007 4:02 pm
- Location: merseyside UK
model 20 us export pistons
Thanks Don. I can design a piston myself on autocad and get a firm here to make one, do you know where i can get all the dimendions from? John
john cavanagh
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model 20 us export pistons
Sorry, I have none, & don't know of any outside an engine although the bikes are not rare here.
Try asking in the Yahoo! forum & if no results, try the North American newsletter.
As Michael says, they do turn up now & then.
According to the spares list, which you will find in the archives, the heads are the same as the 500cc. You should be able to use a piston from the G9 as a reference & the standard bore for the G9B is 69mm.
The tricky part would be the dimentions of the inside structure. Perhaps you can cut a scrap G9 piston in half for access.
If you come up with a solution, please advertize the fact so that others can share.
Cheers, Don.
Try asking in the Yahoo! forum & if no results, try the North American newsletter.
As Michael says, they do turn up now & then.
According to the spares list, which you will find in the archives, the heads are the same as the 500cc. You should be able to use a piston from the G9 as a reference & the standard bore for the G9B is 69mm.
The tricky part would be the dimentions of the inside structure. Perhaps you can cut a scrap G9 piston in half for access.
If you come up with a solution, please advertize the fact so that others can share.
Cheers, Don.