BSA Owners' Club Forum

The BSA Workshop => Twins => Topic started by: Grumpy Geezer on 05 December, 2017, 14:13:44

Title: Tachometer
Post by: Grumpy Geezer on 05 December, 2017, 14:13:44
I am currently trying to source a tachometer for my A10 twin...its a 1959 bike but has an 1962 engine. I have noticed on line tachos have  2-1, 3-1 or 4-1 ratios quoted. How can I establish what ratio I need for my engine so that I can purchase the correct Tacho and cable?.
The intention is to fit the tacho cable to the front crankcase point instead of the earlier version that required an 90deg drive from the right hand cover side (al la Goldie) etc
I am sure the answer is out there!
Aidan
Title: Re: Tachometer
Post by: JulianS on 05 December, 2017, 17:23:07
Tacho driven from oil pump take off at front of inner timing cover is 3;1.

Photo is the Smiths chronometric 3;1 on my 1962 A10. Number RC 1303/03. The can be very expensive.

Just order a cable for a 1960 on Super Rocket. Any decent dealer should be able to supply the correct  2ft 10 1/2  inch item.
Title: Re: Tachometer
Post by: Grumpy Geezer on 05 December, 2017, 17:43:47
Thanks Julian.......3:1 it is ...I can go ahead and get one, the chrono looks fantastic but wow! prices!
Title: Re: Tachometer
Post by: Grumpy Geezer on 05 December, 2017, 17:45:49
I now need to pick up  tacho conversion/kit to fit the front of the crankcase so if you have any ideas of suppliers I would also appreciate that bit of info..
regards

Aidan
Title: Re: Tachometer
Post by: JulianS on 05 December, 2017, 17:59:31
You dont say what you already have, assuming starting from scratch you need;

The inner timing cover - part 42 - 153 casting number 42 - 154.

The cable adaptor and drive spindle.

Oil pump worm with tacho extension.

The first come up on e bay sometimes, the next 2 you can buy new from a good BSA parts dealer.
Title: Re: Tachometer
Post by: Grumpy Geezer on 08 December, 2017, 19:42:23
Thanks Julian.....The tacho drive and pinion etc. are available from Dragan fly so I am sorted. they do a kit with the front plate to pick up on the cable and a screw/unit to engage with the oil pump so it all seems quite simple....thank you again for your advice....
regards

Aidan