The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: coater87 on 21.07. 2017 05:36

Title: What kind of numbers are these!??
Post by: coater87 on 21.07. 2017 05:36
 These are the numbers on a swing arm motor. Whether A7 or A10 I have no idea.

 Any thoughts ?
Title: Re: What kind of numbers are these!??
Post by: Black Sheep on 21.07. 2017 06:32
I suspect the short answer is not the original number stamping.
Title: Re: What kind of numbers are these!??
Post by: duTch on 21.07. 2017 07:32

 Looks dodgy *dunno*
Title: Re: What kind of numbers are these!??
Post by: Klaus on 21.07. 2017 08:25
Looks strange, but I guess the long figures are a Date 19658 can mean August 65.
But whats about the crank inside  *dunno*A7 had a shorter strocke than A10
Never seen befor is the prefix Z.
I had a crankcase stamped DA7 , asking the BSAOC, this combination never left the faktory, but the figures looks like original punshes.
Maybe a Monday engine *eek*
Title: Re: What kind of numbers are these!??
Post by: Bsareg on 21.07. 2017 08:58
I remember  reading an article about a gold star stamped with a BC prefix ( a humble c10 or c11 prefix ) straight from BSAS .  Suppose the chap just picked up the stamps in the wrong sequence .
Title: Re: What kind of numbers are these!??
Post by: JulianS on 21.07. 2017 09:26
The case looks polished. I think an original number has been ground off and this one stamped on.

ZA7 3 does not exist as an original prefix and the stamper might have meant ZA7S forStar twin.

ZA7 was an early long stroke prefix. The inside of the crankcase should give a clue whether long stroke or not.

ZA7S and ZA7 numbers did not reach 19653.

Title: Re: What kind of numbers are these!??
Post by: duTch on 21.07. 2017 11:16
Quote
...ZA7 was an early long stroke prefix. The inside of the crankcase should give a clue whether long stroke or not...

 To save some work,  the timing cover shape(and a few other views) would do the same  *????*
Title: Re: What kind of numbers are these!??
Post by: Tomcat on 21.07. 2017 11:44
Coater87 said swing arm engine.
Should be CA7, CA10 or later for a swing arm engine. Sorry to be the bearer of bad news but I agree with JulianS, cases have been polished and IMHO the stamps don't look factory. It doesn't matter if you have a receipt for it and the registration department in your country don't have these numbers on their computer, they don't know what the numbers should look like.  But, don't go near a concourse competition.  *eek*
Title: Re: What kind of numbers are these!??
Post by: coater87 on 21.07. 2017 12:43
 I do not own this, it's for sale.

 I asked the guy to send me pictures of the motor numbers. This is what I got from him.

 I explained the numbers were bad, it's not a rocket gold star super ultra rocket motor. Then I explained it may not even be an A10 motor, but an A7.

 I think I *****  him off,  which is too bad because the crankshaft may be a good one. But who knows without tearing into it. *dunno*

Lee
Title: Re: What kind of numbers are these!??
Post by: duTch on 21.07. 2017 13:29

 
Quote
.....  which is too bad because the crankshaft may be a good one. ...

 Maybe best pretend it's not a good'un for peace of mind *dunno*...... or go hard and live dangerous *work* *fight* *beer* 
Title: Re: What kind of numbers are these!??
Post by: coater87 on 21.07. 2017 13:45

 
Quote
.....  which is too bad because the crankshaft may be a good one. ...

 Maybe best pretend it's not a good'un for peace of mind *dunno*...... or go hard and live dangerous *work* *fight* *beer*

 He is up near 800.00 U.S. for this really rare, one off, Super Ultra Rocket Gold Star motor.

 Taking a chance is one thing, wiping my butt with a wad of money is another. *eek* *smile*

 Someone WILL buy this though, next month it will be on EBAY for 1500.00....

 Lee

 
Title: Re: What kind of numbers are these!??
Post by: Black Sheep on 21.07. 2017 14:15
I hope the eventual purchaser will be wearing oven gloves 'cos it looks red hot to me.
Title: Re: What kind of numbers are these!??
Post by: chaterlea25 on 21.07. 2017 20:03
Hi All,
Lee,
On any BSA crankcases A and B series I have looked at there is a date stamp,(in UK format) usually inside the timing case or outside on the case more or less under the magneto
Definitely a re stamped number
Are there any more pics on the ad?
Go on give us a laugh *smile* at $800 he will be looking at it forever ??

John