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Messages - JulianS

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Twins / Re: A65 Pistons
« on: 18 August, 2017, 09:21:24 »
Then they changed the Spitfire pistons again in early 1967, compression now down to 9:1. From parts service bulletin G40.

Twins / Re: Breather dripping oil when running
« on: 17 August, 2017, 18:05:53 »
If it is a lot then could be any of these;

Breather not properly assembled - wrong thickness cork.

Excess crankcase pressure caused by worn rings/bore/guides, rings not bedded in, poor scavenging of oil from sump.

But expect a little after a good hard run.

If bike wet sumps then it will blow oil until excess cleared.

Twins / Re: A65 Pistons
« on: 17 August, 2017, 16:52:41 »
They are later than the 1966 parts book - they were introduced in parts service bulletin GA22 from November 1966. See below photo. 68 907 is the piston casting number the piston complete with rings and pin parts number drops by 1 to 68 906.

Twins / Re: A65 Pistons
« on: 17 August, 2017, 14:49:58 »
Both numbers are casting numbers for 10.5:1 Spitfire Mk2 pistons. The numbers for the complete pistons drop one to 68 792 and 68 742.

Why 2 different numbers?

Around that time there were severe problems with piston seizures and the later part may be slightly different.

Attached first piston list from 1966 parts book and the second from parts service bulletin G39 from February 1967.

Twins / Re: Rich running Super Rocket
« on: 17 August, 2017, 10:20:28 »
The 420 main jet given for some models can be a bit too big. Mine runs on a 400 which is good for a long fast run but soots when pottering around.

Mine has 400 main, 3 1/2 slide with needle in middle groove and an S and B air filter from Hitchcocks.

Expect to have to vary the original settings with the changes in fuel over the past 50 years.

Sometimes the original monoblocs with the thick O ring are assembled with a fibre wsher under the float needle seat which raises fuel height and can cause richness and/or flooding. The washer is only for the later monoblocs with thin concentric type O ring and a machined recess to take washer.

Twins / Re: Plunger A10 Front Wheel
« on: 16 August, 2017, 09:21:35 »
Cross section of the hub below.

Twins / Re: A65 OIF Wheel rebuilding 1972 Conical Hubs.
« on: 15 August, 2017, 18:16:43 »
The 1971 workshop manual helpfully gives the offsets.

Singles / Re: C15 timing
« on: 15 August, 2017, 09:45:05 »
Photos below, first from 1964 Lucas Equipment for BSA, second the 1965 issue, third the parts fitted to BSA from 1965 issue.

Might help you figure out the spring numbers.

I would phone some of the larger dealers, C and D Autos for example.

You can see the distributor springs are different parts.

If your a/r is giving trouble electronic is the way to go.

Twins / Re: Update from Old Biker
« on: 15 August, 2017, 09:13:05 »
It can be done but it is more than just plug in the later brake plate.

The original brake has 1 1/8 inch wide braking surface in the hub and straight pull spokes.

The later hub, for which the TLS is designed, has a 1 5/8 wide braking surface, and a verticle spoke flange with angled spokes. The flange also adds strength to the hub.

The TSL brake is designed for later fork bottoms - the slot on the brake plate does not offer safe engagement with the early A65 forks with full width hub. Either the brake plate needs the slot building up or the lug on the fork leg needs extending.

You can use the original hub but it is better with the later item.

It is worth the trouble, the brake is vastly improved over the original.

First photo shows the difference in lugs, early fork at bottom and TLS, 1968 type, fork bottom at top.

Second photo shows the slot on TLS brake plate.

Third shows up to 1965 type full width hub.

And last shows the 1968 on full width hub.

Triples / Re: re import
« on: 13 August, 2017, 10:03:25 »
You need a frame number which can be dated by one of the UK organisations approved by DVLA - BSAOC for example.

What is the US dealer verifying?

If it is not a proper frame number then it cannot be dated.

Singles / Re: C15 timing
« on: 13 August, 2017, 09:59:31 »
The springs need to be strong hold the auto advance unit in the fully retarded position when engine at rest. Slack no good.

Singles / Re: BSA B33 sticky exhaust valve advise please
« on: 11 August, 2017, 19:00:50 »
Could be build up of carbon on valve stem causing slow closing?

Twins / Re: A50/65 - Rear Brake Light Switch
« on: 11 August, 2017, 15:52:25 »
Its the one before the one before the one that is now fitted!!

Twins / Re: A50/65 - Rear Brake Light Switch
« on: 11 August, 2017, 13:57:03 »
There is a limited arc of contact within these D shaped switches.

There is similar fitted to my A10 - the D bit is the same just the mounting bracket and lever differs.

To get it to work properly it seems to me that trial and error with position is the way forward. If it comes on too soon light will go out before pedal fully depressed.

Below is photo shows the inside of such a switch, the moving contact sits in the bracket indicated by the arrow.

Twins / Re: Steering lock removal 1972 Thunderbolt
« on: 11 August, 2017, 08:58:58 »
I would think that the washer is driven in to prevent a prospective thief from removing the grub screw with ease, and I agree careful drilling would seem to be the way.

BBB are listing the washer as an aluminium disc.

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