The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: Beriano on 27.12. 2014 21:02

Title: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: Beriano on 27.12. 2014 21:02
I,m new to this forum,following a recent con rod failure on my '48 rigid framed A10 (1950 engine) I am in the process of gathering bits for my rebuild. In this connection I have acquired A large journal crank and already have a spitfire cam if needed and also have thick flange barrell.New A10 pistons tend to be much more expensive than A65 pistons, as I intend to increase the compression can anyone advise if the A65 pistons will work as direct replacements.?.....many thanks in anticipation of a reply (hopefully)
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: trevinoz on 27.12. 2014 21:18
The short answer is no.
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: Triton Thrasher on 27.12. 2014 21:24
A slightly longer answer:

 I see no reason why A65 pistons would have anything at all in common with A10 pistons.  The A65 bore is much larger, which makes me think you haven't even Googled this.

What was your "rod failure" and what was the reason for it? If the rod broke, the usual reason is a big end seizure. The usual reason for a big end seizure is oil supply failure.

What compression ratio do you want and why?
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: Beriano on 27.12. 2014 22:07
Rod failure was due to lack of oil....my son took bike out for  spin when I was away without checking level beforehand....re compression increase not yet decided.thanks for your help.
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: beezermacc on 27.12. 2014 23:08
A10 pistons are less than £100 a pair.
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: RichardL on 27.12. 2014 23:43
Beriano,

First,  *welcome*.

Second, we love pictures of bikes in all states of repair and rebuilding. Also, they help when trying to give advice, opinions or chiding (the latter always in good fun).

Third, you are closer to Aberystwyth than, I'd say, 99% of forum members. You should take a ride with your parts over to SRM in Aberystwyth and talk to Gary Hearl. He has always been generous with advice and information and can help out (a lot) with parts. (You can get cheaper parts but, perhaps, not better.)

Regards,

Richard L.
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: BSA500 on 28.12. 2014 10:37
A10 pistons are less than £100 a pair.
Beezermacc,
I am on the lookout for a set of A7 +20 pistons. Whereabouts do you get yours from as I am having trouble geting some for that sort of price?
thanks Andy
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: beezermacc on 28.12. 2014 14:17
I stock the new Hepolites but they are only available for A10's. JP pistons are available for A7's but they're twice the price.
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: RichardL on 28.12. 2014 15:24
...oh, and let me also mention there is a gentleman in Cheshire by the name of Andrew who runs a business called Priory Magnetos, has been very generous with his knowledge, appears to have quite a selection of parts at fair prices, and sometimes goes by the name Beezermacc.  *smile*

Richard L.
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: BSA500 on 28.12. 2014 20:37
Yep seen the prices for JP pistons  *eek*. I was speaking to the guy doing my rebore(once I have the pistons) and he has people bringing what they believe to be Helopite(sp) pistons, and he has to tell them that the box may be helopite but pistons were not. Be careful what you buy folks  *sad2*
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: Triton Thrasher on 28.12. 2014 21:40
Yep seen the prices for JP pistons  *eek*. I was speaking to the guy doing my rebore(once I have the pistons) and he has people bringing what they believe to be Helopite(sp) pistons, and he has to tell them that the box may be helopite but pistons were not. Be careful what you buy folks  *sad2*

They're Hepolite pistons all right. Modern Hepolite pistons are made by JCC in Taiwan.

They're pretty good.
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: bsa-bill on 28.12. 2014 21:56
and HP sauce is now made in Holland, has been for many a year, I haven't bought any HP since they shifted, changed to Daddy's, my choice but if they thought every body choose the same they might not have moved - ok point made
now pistons, the last ones I bought were made in Oz I believe, seem ok so far
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: Topdad on 29.12. 2014 11:23
bloody hell Bill you just confused half the forum with mention of HP and Daddies ,to enlighten ..... Both were British favorite sauces to accompany our world wide famous healthy fry up for breakfast , to save money a company and trans HP ( HP = Houses of Parliament) to the continent ,agree totally with you bill by the way , back to topic gents regards bob  *wink2*
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: bsa-bill on 29.12. 2014 11:51
bloody hell Bill you just confused half the forum
ah only 50% success then  *smiley4*v- yes apologies all

back on track I believe I bought JP pistons for my Flash way back in 99 and understood they were made by Hepolite (or the remains of) what did have a Hepolite box were the liners I bought at the same time, pretty sure they came from C&D and they are a bit particular about what they sell, haven't bought much from them lately, no reason really except it's so (too) easy to do stuff online, I did email order stuff from them tho, must look back and see if their site is fully online

Just had a look - no just a front page and tel No
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: morris on 29.12. 2014 19:49
Bit off topic but anyway...
bloody hell Bill you just confused half the forum with mention of HP and Daddies
HP, although indeed made in Holland, still my favourite, but may have a go at Daddies next time...
A plate of chips, a fried egg, some Haywards onions, topped with HP or Hellman's and flushed through with a pint of Old Speckled Hen.
Think I now confused all of the Brits on this forum *smile*
BTW, did you guys read the small print on Bird's custard lately?
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: Triton Thrasher on 29.12. 2014 20:30

BTW, did you guys read the small print on Bird's custard lately?

Does it no longer contain birds?
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: morris on 29.12. 2014 21:02
Does it no longer contain birds?

Well... yes but no but yes but of German origin...
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: bsa-bill on 29.12. 2014 21:14
a wild guess - "contains eggs"
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: morris on 29.12. 2014 21:42
a wild guess - "contains eggs"
Still no eggs. But entirely made in Germany with German milk... *shh*
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: bsa-bill on 29.12. 2014 21:59
 
Quote
entirely made in Germany with German milk..
They have no cows over there then *smiley4* OOPs another wedge in our relations with Europe

   Beriano - you must be wondering what on earth is going on, however the first answer to your post was really  definitive
Keeps us informed of your progress and pics
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: Topdad on 30.12. 2014 10:53
good morning Morris, just read your post re chips egg and pickled onions plus ample doses of sauce mayo and speckled hen , I 'm not confused ,just grateful for the input if/when we meet i'll remember to stay well "UP WIND " from you!! if you order that .  *smile* *countdown* many thanks for the moderators leyway with this off topic banter ,cheers Bob.
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: muskrat on 30.12. 2014 12:13
If you could fit A65 pistons in an A10 it would make about 750cc. A A10 crank in a punched out A65 can get about 900cc *eek* *work*
Cheers
 *shh*
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: Rocket Racer on 03.01. 2015 04:00
I,m new to this forum,following a recent con rod failure on my '48 rigid framed A10 (1950 engine) I am in the process of gathering bits for my rebuild. In this connection I have acquired A large journal crank and already have a spitfire cam if needed and also have thick flange barrell.New A10 pistons tend to be much more expensive than A65 pistons, as I intend to increase the compression can anyone advise if the A65 pistons will work as direct replacements.?.....many thanks in anticipation of a reply (hopefully)

Photos would be nice!
now given a thick flange barrel is big fin, you also mention a sports cam...what state of tune are you aiming for? Keeping the iron head?
Cake Street Classics certainly used to stock wiseco pistons.
I personally avoid JP's like the plague.
I had a ride on a mates cooking '55 flash on New Years Day, delightful. Smooth as. Not a go fast bit to be found on it. Quite a different beastie to my methanol twin carb track bike, but no worse for it.

A65 pistons not an easy solution, the stock flanges don't have enough meat in them to go beyond 72.5mm
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: Gerry on 04.01. 2015 23:43
Hi Guys, JP pistons and rings are made here in Adelaide and sold all over the World. Haven't bought any myself from them but have purchased rings from them over the counter. Cheers. Gerry
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: Gerry on 04.01. 2015 23:45
Hi again, Here's J P Engineering web address - http://www.jp.com.au/JPPistons.html  Cheers. Gerry
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: Rocket Racer on 05.01. 2015 01:29
Thanks to a very wicked fellow forum member  *wink2* I've just bought some suitable pistons for my a10  *yeah*
certainly not under a 100 quid though

Can't wait to try these out   *respect*
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: Brian on 05.01. 2015 01:55
I had a look through my books and while I couldnt find 67-554 I did find 67-1554 which are 8.75-1 pistons. Looking at the tops of the pistons I think that would be about right.

I'm still searching but somewhere among my info I have listings for BSA pistons that go up to 14-1. I will find it sooner or later.
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: RichardL on 05.01. 2015 05:03
Brian,

I saw the listing from which RR bought these pistons. Seller was listing as 14:1,  which makes more sense to me than 8.75:1. My little dome-tops are considered 9:1 and there is a lot more piston above the top of the bore with these. I am assuming RR was looking for high compression, after all "R" number two is for "racer". (RR, I'm not trying to talk for you.)

Richard L.

Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: Brian on 05.01. 2015 05:09
The pistons in the picture certainly do appear to have high crowns but the valve recesses are shallow so I think the gudgeon to crown height is low. Maybe someone can identify the number on the top more accurately.
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: Rocket Racer on 05.01. 2015 05:54
553 or 555 are 14:1 have yet to find ref to 554, but assuming they are 70.5 they look more dramatic than a set of 10.5's so I'm hoping they are as advertised 14:1 methanol pistons  >:D
Which should be very interesting...
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: Brian on 05.01. 2015 07:00
The number stamped on the piston, in this case 67-554, is the number for the bare piston. The numbers in the parts books usually is for the complete piston assembly which makes it difficult to identify pistons unless you have detailed information on the numbers which I do not.

Whatever the case I hope these pistons work out well for you RR, good luck.
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: trevinoz on 05.01. 2015 20:12
I would say most definitely higher than 10:1.
I had a set of 10:1 many years ago and they weren't anywhere as high as that.
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: Rocket Racer on 06.01. 2015 01:25
Once I've got them fitted and had a run I'll provide some feedback via my road racing sidecar thread, but don't hold your breath this wont be before March.
There aren't that many practical uses of 14:1 pistons on a typical A10, so lucky for me Bender only lives on the track. He would be lost without his alcohol  *beer*
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: bsa-bill on 06.01. 2015 10:00
A10 pistons are less than £100 a pair.

Well these ones are,

http://www.ebay.co.uk/itm/Hepolite-piston-kit-11062-STD-To-fit-BSA-A10-650cc-/390968118392?pt=UK_Motorcycle_Parts_13&hash=item5b07840c78
Title: Re: Can A65 pistons be fitted to an A10 as direct replacement ?
Post by: Rocket Racer on 06.01. 2015 23:48
A10 pistons are less than £100 a pair.

Well these ones are,

http://www.ebay.co.uk/itm/Hepolite-piston-kit-11062-STD-To-fit-BSA-A10-650cc-/390968118392?pt=UK_Motorcycle_Parts_13&hash=item5b07840c78

perfect for a road bike, the sort of thing I'll fit to my daughters C11...as it needs a rebore and +60 piston