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Technical Discussion Forum / Re: 25/25 watt NOS bulbs
« Last post by Thomas on September 13, 2019, 04:29:32 PM »
Thanks!  :)
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Technical Discussion Forum / Re: 25/25 watt NOS bulbs
« Last post by singleminded on September 13, 2019, 01:21:52 PM »
www.norbsa02.freeuk.com/goffybulbs.htm

Paul should have standard bulbs as well as the halogen ones.
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Technical Discussion Forum / 25/25 watt NOS bulbs
« Last post by Thomas on September 13, 2019, 09:15:49 AM »
Hi all! Does anybody have a source for BA15d 25/25 watt NOS bulbs? Cheers, Thomas
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Technical Discussion Forum / Re: 1935 Model 8 Piston rings, advice please.
« Last post by Exstress on September 12, 2019, 10:44:10 PM »
Thanks for the replies.

The Piston is a BSA B31 made by JP and with a compression ratio of 6.5.1 which is obviously not suitable.  I will try and get the correct one this time.
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Technical Discussion Forum / Re: 1935 Model 8 Piston rings, advice please.
« Last post by singleminded on September 12, 2019, 06:57:59 PM »
If the B31 piston you got is a standard compression ratio the the hieght between pin and crown will be wrong.Hepolite number SW10962, described as Flat with Valve pockets.
The 7.75:1 has, according to my book got the same compression height..Hepolite number 9939, described as Dome with valve pockets.
Do you have a Hepolite number for the one you bought.
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Technical Discussion Forum / Re: 1935 Model 8 Piston rings, advice please.
« Last post by wessex_man on September 12, 2019, 02:45:46 PM »
Looks like it's going to be a bit on the low side compression wise and requires heavy modification. I'd think again.

You definitly could do with one like you have taken out.  Hepolite part number 3238 I had a +40 and +60 both gone now the last one at last Shepton.

The later ones have a larger gudgen pin than the earlier but the small end can be reamed to suit.
here's some pic's I took when selling them.







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Technical Discussion Forum / Re: 1935 Model 8 Piston rings, advice please.
« Last post by Exstress on September 12, 2019, 02:08:54 PM »
If there is enough meat in the barrel then you might find a slightly bigger but more available piston..
A 1946/1958 B31,, 7.75:1 cr is 71mm, has the same compression height and gudgeon pin but may need to be shortened..There are also some 600/650 twin pistons that may work..My Hepolite book is not very comprehensive I'm afraid.
I have a 9A and pistons are going to be a problem for me in the future..I'm sure one of the Model * owners out there has had the same problem and can give better advice..
Post this to the facebook page as well, the more people that see your question the better..John
John, I have got myself a B31 piston which unfortunateley is nothing like the piston fitted to my model 8.  Can you advise if the piston on the right is a B31 or perhaps the one fitted in my bike is wrong anyway.  The distance from pin to crown is substantially different.
Regards, John
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Technical Discussion Forum / Re: 1935 Model 8 Piston rings, advice please.
« Last post by Exstress on September 05, 2019, 03:57:59 PM »
Apologies..... Its a BSA B31 piston manufactured by JP pistons.  Advertised at 71mm diameter.  My fingers sprung into action before my brain!
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Technical Discussion Forum / Re: 1935 Model 8 Piston rings, advice please.
« Last post by singleminded on September 05, 2019, 07:37:56 AM »
I thought that the B50 was a 500 with an 84mm piston? is there another B50.
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Technical Discussion Forum / Re: 1935 Model 8 Piston rings, advice please.
« Last post by Exstress on September 04, 2019, 06:55:42 PM »
Thanks for the replies.

I have found a supplier has a Hepolite Piston showing in stock but he hasn't actually found it yet!  He also has Model 8 valves and end caps. I will confirm if this is the case...….

If not and I go down the B50 piston route, will I be ok to get a standard piston at 71mm diameter for my cylinder that has never had a rebore but needs one now?

Thanks, John
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