Author Topic: Time for a rebuild  (Read 3766 times)

Online BSA500

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Re: Time for a rebuild
« Reply #30 on: 02.01. 2015 13:31 »
Re the crank the journal measures up nice and 'round' no hint of being oval. I shall prob get the -20 timing bush to give him plenty of metal to bore out  *smiley4*
Re the pistons. Those have been in these STD bores for the last 15 years with one ring change 5 years ago due to the lack of wear. The scratches have only occurred in the last 5 years. I suspect it could be down to lack of air filter *dunno*. No dry assembly always plenty of oil used, proper running in but after that plenty of revs and snappy get aways at the traffic light Grand Prix  ;). I put the lack of wear on the crank etc down to the fact I changed the oil pump(after the original pump failed) to a cast iron bodied SRM pump. She has done circa 50,000 in the last 15 years so not so bad(have to admit this is the second crank after I cracked the big end journal when the timing slipped and the oil boiled ooopps)

Online BSA500

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Re: Time for a rebuild
« Reply #31 on: 14.01. 2015 09:18 »
I have located some pistons at a good price but was wondering if anyone has used this shop/store and how was their experience. Its www.classicbikeshop.co.uk

Online chaterlea25

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Re: Time for a rebuild
« Reply #32 on: 14.01. 2015 16:18 »
Hi,
I cannot see any A7 pistons on their website ??
(or am I missing something??)

John
1961 Super Rocket
1963 RGS (ongoing)

Online BSA500

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Re: Time for a rebuild
« Reply #33 on: 14.01. 2015 20:51 »
No your right, but when I inquired about the price etc they came back with a quote for a set of A7 pistons +20 of £100 incl vat(£3 p&p)

Online BSA500

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Re: Time for a rebuild
« Reply #34 on: 02.02. 2015 13:51 »
Piston update they do not stock A7 pistons( http://www.classicbikeshop.co.uk/). I have ordered mine from Draganfly(on back order) seems nobody stocks A7 pistons these days. A10 on the other hand how many do you want sir :(

Offline muskrat

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Re: Time for a rebuild
« Reply #35 on: 03.02. 2015 11:24 »
G'day BSA500.
I just had a quick look at this list (download) www.britcycle.com/products/Pistons_Rings.pdf
The C15, C25 and B25 are 1mm bigger,Notrun 500 twin pistons are the same bore size. You'd have to check the pin size and crown height.
I used to run std A75 pistons (67mm) but had to use A10 rods shortened by 2.5mm in my A7SS racer (crown height was shorter).  *eek*
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Online edboy

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Re: Time for a rebuild
« Reply #36 on: 03.02. 2015 19:31 »
norton pistons would be difficult as the valve recesses are offset compared to bsa pistons. i m after +80 pistons for an a7 and in the same boat. t150 pistons are close but have a higher dome so what about a spacer at the cylinder head muskrat? have you looked at wiseco pistons?

Offline muskrat

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Re: Time for a rebuild
« Reply #37 on: 04.02. 2015 08:27 »
To use T150/A75 pistons you'd need to space the barrels 10mm *ex*. Don't know of a Wiseco that fits.
Try your local engine re conditioner. They have books of piston sizes.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline Rocket Racer

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Re: Time for a rebuild
« Reply #38 on: 05.02. 2015 00:28 »
Not wishing to turn this into another some pistons are crap thread, I would say take your time with getting pistons that suit. There are brands I won't touch with a barge pole, I think they are made from recycled aluminum windows.
Try and find some NOS ones, tricky I know but worth the effort of a big seize
A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
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Offline Rocket Racer

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Re: Time for a rebuild
« Reply #39 on: 05.02. 2015 00:42 »
http://www.vintage-motorcycle.com/index.php?language=en&site=4&pid=113&id=21072&limit=0

I'd be thinking about these if I were you, NOS is always my preference, or are these the wrong A7... *eek* doh always forgetting the mk1/mk2 thing. Anyway good luck
A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
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Offline terryk

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Re: Time for a rebuild
« Reply #40 on: 05.02. 2015 07:05 »
Hi BSA500 I have a number of NOS BSA A7 piston sets both long and short stroke what compression ratio were you chasing?
I'm in Australia so post cost need to be taken into consideration.
cheers Terry K
1950-53 A10 rigid/plungers, 1958-61 A10 super rockets, 1947-50 A7 longstrokes, 1949 Star twin,
1951-54 A7 plungers, 1940s M21, WDM20s,
1948-50s B33s rigid/plunger/swingarm, 1948-50s b31s rigid/plunger/swingarm

Online BSA500

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Re: Time for a rebuild
« Reply #41 on: 05.02. 2015 08:44 »
Thanks for the replies and offers. I currently have a pair on order from Draganfly so fingers crossed they come soon. They reckon they will  :!

Online BSA500

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Re: Time for a rebuild
« Reply #42 on: 05.02. 2015 08:46 »
Oh the engine is a 1957(in a 1960 frame) alloy head currently sporting 8.5:1 in worn out standard bores. I have plenty other things to do to it so a little extra time won't hurt(and its effing cold out I normally ride the winter so a winter in the car is quite new to me  *smile* )

Online edboy

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Re: Time for a rebuild
« Reply #43 on: 05.02. 2015 19:29 »
its a shame otj are no longer around in kent. a set of cord piston rings would have kept you going through the winter. do you remember those? steel rings for worn out barrels and i believe otj were a main supplier.

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Re: Time for a rebuild
« Reply #44 on: 08.02. 2015 20:11 »
OTJ was just up the road for me so yes its a shame they went  *sad2*