Author Topic: engine numbers  (Read 1201 times)

Offline mike667

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engine numbers
« on: 23.05. 2009 22:22 »
Hey gang
  screwing around in the garage - I see that my engine numbers on my 61 A10 is  DA1014115 HC - does the HC mean high compression ? If so  I'm surprised,  as the bike  is fairly easy to kick over (in comparison to my commando)and i don't think the motors to worn as no oil consumption etc
thanks

mike

Online groily

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Re: engine numbers
« Reply #1 on: 24.05. 2009 17:50 »
Who knows what's in that there engine after all these years? Unless you open it to inspect . . . . 
I also have some dubious stamps averring 'high compression', and yet the pistons are a very nice pair of flat top things that will hopefully last for ages and allow the nether regions to do the same. Personally, as a relatively high mileage 52-week a year person, I reckon a decently maintained cooking engine can often be a better bet than a more rorty one that only works right on alternate Tuesdays. Especially when we get out mostly on days that aren't that Tuesday . . . . Although I am of course all ears and momentarily jealous when people who know tell me that a 357 cam and something well north of 8:1 c.r. is the d's bs.
But if I truly deeply madly wanted them, I wouldn't have sent the poor dog to the vet . . . . . and I'd have bought shares in an octane boost company  . .
Bill

Offline dpaddock

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Re: engine numbers
« Reply #2 on: 24.05. 2009 20:34 »
According to "Super Profile - BSA A7 and A10 Twins", the HC stamp confirms that "high compression pistons have been fitted". Because you seem to have a Golden Flash engine, I imagine this means (perhaps) Royal Tourist (the US market GF) pistons having 8.3 cr instead of the home market 7.25 pistons.

Perhaps someone else has better info for you.

David 
David
'57 Spitfire


Offline mike667

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Re: engine numbers
« Reply #3 on: 24.05. 2009 21:32 »
thx Guys!
 
  i suspect the orginal pistons are in the motor in my royal tourist -  but thats only a guess since i havn't opened it up and the previous owner never did either after talking to him - guess i shalln't think about it to much unless it goes boom
thanks!
mike

Offline beezalex

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Re: engine numbers
« Reply #4 on: 26.05. 2009 18:09 »
Pretty much any A10 is gonna be easy to kick over compared to a commando.
Alex

Too many BSA's


Offline 69Bonni

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Re: engine numbers
« Reply #5 on: 27.05. 2009 15:13 »
Hi Mike, All,

Take a look at post http://www.a7a10.net/forum/index.php?topic=932.0

I guess as they came from the factory they would have the hotter cam and HC pistons, but we must not loose site of the fact that most of our bikes are probably 50 odd years old and a lot of things can happen in that time!

I would be to frightened to admit to some of the things i did to bikes when i was a kid to get me to work on Monday morning and if it meant sticking pistons out of an old Flash into a Super Rocket then thats what youd do. Old bikes today bear no resemblance to the bikes back then, most (well the ones i had) were painted all sorts of colours, held together with Jubilee clips and Black and White checker tape (made them go faster) and when you blew it up you either bought another one or got another engine from the junk yard, im suprised any bike has matching numbers nowadays 40years on!

groily is right a Lower compression engine is less highly strung and easier to live with than a hot engine i actually dropped the compression ratio of my RR

Have fun and enjoy your bikes

Steve
Kind Regards
Steve Rickman