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Messages - JulianS

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Singles / Re: Rectifier
« on: 28 February, 2017, 12:29:30 »
This is a modern replacement. They cost around 5 from e bay sellers.

The terminal set at right angles to the other 3 is the positive dc output (to earth if you have positive earth). usually marked with a plus.

The terminal diametrically opposite is the negative dc output.

The other 2 termials are alternating current input from the alternator. May be marked with a squiggle to signify ac.

Generic wiring diagram from Lucas manual for bikes with C15 type ignition and lighting switches below.

Pre War / Re: need help with starting procedure bsa round tank 1924
« on: 28 February, 2017, 10:03:32 »
Arthur is quite right. A bike which has been left for decades in poor conditions will contain unknowns and it is best to find them before risking those near 100 year old parts which will be very difficult to replace. It will be hard enough to source the obvious missing parts. There may even have been an engine problem which caused it to be taken out of use all those years ago.

I suggest you find as much literature as you can concerning your bike and study. There is a lot out there. Knowledge is power.

Photos from 1924 catalogue.

Twins / Re: A65 Early clutch changes
« on: 27 February, 2017, 10:20:45 »
Yes it looks like it is possible.

BSA dealt with it in Parts Service Bulletin G24 from June 1963 - except for 68 3245 which I think was an earlier modification.


Twins / Re: Non-branded supermarket petrols
« on: 26 February, 2017, 12:08:13 »
In the mid 1990s the publicity surrounding the introduction of unleaded was almost completely negative, resulting in high levels of anxiety for some of us. Fortunately most of the predicted problems have not happened. My own experience with C11, B25 B40 plus an iron head A10 and alloy head A10 has been that I suffered no apparent recession. Use included regular commuting to work on the A10s.

I suspect that we cause more recession ourselves by over zealous valve seat recutting and grinding.

Ethanol is a different issue, though it is not new in petrol. Remember Cleveland Discol petrol fro the 1950s and 1960s?

The problem I had was with the ethanol disolving the old tank sealer, forming a sticky varnish over carb slide which caused carb to stick open. Not nice.

Solution - strip old sealer and reseal with ethanol resistant.

The other issue was that the petrol tap corks shrank with ethanol fuel allowing fuel to seep.

Solution - new lever action taps.

The Star and Garter / Re: tax discs
« on: 25 February, 2017, 10:22:25 »
Lost too many tax disc over the years due to the holders fracturing with vibration so happy to be done with the need for one!

Twins / Re: A65 Lightning Clutch Retaining Nut
« on: 24 February, 2017, 20:58:24 »
The way I see it is that the 4 spring clutches up to 1965 had a plain nut and lock washer and the 1966 on 3 spring clutches had a lock nut.

The cross section below is from "Motor Cycle" 2 September 1965 when the new clutch was introduced for the 1966 season. You can see the orientation of the nut - but also note that it shows a lock washer.

The second photo is from the 1966-68 workshop manual and again shows the orientation of the nut but no lock washer.

The saw cuts show in both.

Twins / Re: A65 Lightning Clutch Retaining Nut
« on: 24 February, 2017, 19:26:36 »
The original nut would have been an all metal aerotight type lock nut. These nuts have saw cuts. If your bike is still fitted with such a nut then it will be clear if it still has any "lock" left in it.

I would suggest use of a Loctite thread locker to be certain.

These nuts had a torque setting of 65/70 ft lbs.

The nut 68 3300 was changed in 1967 for a simliar one with better material specification part 68 3320. This was covered in parts service bulletin G40 from February 1967 part of  which is in the photo.

Singles / Re: B31 tyre sizes for a 1958 bike.
« on: 24 February, 2017, 19:17:26 »
The B33 of the same year was fitted with a 3.50 x 19 rear tyre. As the wheels are the same the slightly wider tyre would suite your bike.

The Star and Garter / Re: Light bulbs
« on: 23 February, 2017, 17:54:07 »
Yes you need a 12 volt battery.

I use a YTX7L-BS in my 1962 A10. Fits well with the wire clip type battery fixing. Lots of different makes - Yuasa, Lucas etc

It is a sealed battery after the electrolyte has been added  so no vent or acid spillage.

Singles / Re: C15 ss Max speed
« on: 23 February, 2017, 16:55:09 »
A larger gearbox sprocket will not increase maximum speed unless the bike was undergeared for the power before the change. You will reduce the acceleration and possibly the top speed unless you reduce the weight of bike and rider significantly.

The blue top service sheet below from 1963 shows that the factory actually reduced the gearbox sprocket from 17 to 16 teeth on the SS80 and got a higher maximum speed.

Looking through the 1964 USA brochure that shows the standard gearbox sprocket as 16 teeth.

There were quite a number of engine gearbox and rear wheel sprocket variations available for the competition models some of which show in the second photo of a US bulletin.

The Star and Garter / Re: Light bulbs
« on: 23 February, 2017, 12:22:29 »
Look at Paul Goffs website for the bulbs.

Think about changing the speedo bulb for LED also because the originals can be vibration prone and fail.

If you put a halogen bulb in an original or repro British pre focus headlight  unit you will get a brighter light but the beam pattern will not improve.

Singles / Re: C15 ss Max speed
« on: 21 February, 2017, 10:04:08 »
I think you are expecting too much from an over 50 year old C15.

Not only the engine and cycle parts but also the build and weight of rider have significant effect on performance of a small bike.

The test bikes in the magazines were probably collected by the tester from the BSA factory and would in all probability been in top condition set up properly by factory staff.

The first photo shows an extract from the road test of a standard C15 from "Motorcycling" February 22 1960. You will see that the rider got 70 mph going down hill.

The second and third photos are an extract from the road test of a C15 SS80 from Motor Cycle June 1st 1961. You will note the tester comments about cruising on the M1.

Reading the tests I think that if you can get a reliable anytime top speed of 60 - 65 then it is not doing too bad.

Pre War / Re: Bsa magneto repair
« on: 21 February, 2017, 09:22:01 »
Yes it is a tight fit.

Presuming it is a ring cam magneto you need 2 slim well fitting 4 BA spanners such as "Terry" spanners or a set of magneto spanners (search E bay lots to be found there). Even then you might have to file off an edge of spanner to get best access.

The Star and Garter / Re: Handy hint
« on: 20 February, 2017, 19:06:11 »
This photo might help with the brake shoe plates. (someone turned the edge off the brake plate!)

Twins / Re: A65 Piston advice
« on: 20 February, 2017, 16:20:09 »
My alloy head A10 is on GPM 8.75:1 pistons. Goes fine on ordinary grade fuel no additives. Tried premium grade and it does not seem to make any difference. Have not tried supermarket petrol.

Tried it on 7.25;1 new hepolites and definate drop in power felt.

The new hepolite rings were very poor quality and had not bedded in over 1000 miles. Some dealers who sell the new hepolite pistons will not sell the new hepolite rings because of the poor quality, they fit Italian rings.

So next time I need pistons it will be either GPM or new old stock real Hepolites.

Iron head A10 pinked a lot on GPMs.

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