The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => Frame => Topic started by: MrShifta on 28.04. 2021 21:09

Title: Imported speedo/tacho drive thread size.
Post by: MrShifta on 28.04. 2021 21:09
As the bike I am building is far from factory spec, I sold the original Smiths clocks to fund some of the rebuild costs. I sent for a pair from a U.K. supplier of Indian made ones.  I have come to fit them to the U.K. supplied drive cables and not only is the square hole shaped like an egg, the mounting screws are at 3o'clock and 9 o'clock.  The drive outlet is dead centre so fouls the originals brackets and to top it all the cable mounting threads are too big.

I don't suppose anyone with more sense than me knows the standard Smiths thread on a clock ?

Don't be too hard on me, I just can't afford Smithc clocks.

Thanks for any help you can offer.

 
Title: Re: Imported speedo/tacho drive thread size.
Post by: Rex on 28.04. 2021 21:23
Those Indian things are about twenty quid on Ebay, so just buy a couple with the correct British-sized cable unions, although I believe Hitchcocks can supply replacement cables with the larger fittings on the end.
I have to say though that flogging off the original clocks to fund resto work is a little extreme... *conf*
Title: Re: Imported speedo/tacho drive thread size.
Post by: muskrat on 28.04. 2021 21:24
G'day Barry.
When I put an Indian speedo on my Cafe I used a Royal Oilfield cable and modified the gearbox end. As for mounting, necessity is the mother of invention, I used stainless coffee mugs with the handle removed  *eek*
Cheers
Title: Re: Imported speedo/tacho drive thread size.
Post by: Bsareg on 28.04. 2021 22:03
Cpc Eng in Redruth make stainless bracket that fit the BSA top yoke and takes the indian clocks.
Title: Re: Imported speedo/tacho drive thread size.
Post by: MrShifta on 29.04. 2021 10:54
Thanks for your input lads, Rex I did have to have a word with myself before I sold them but as they were not from the Flash but were DBD34 gold star ones the £500 paid for a crank regind, a rebore and pistons plus a pair of good crankcases. 

In all the bits that came in the boxes that were not for the bike made almost £1500 so helped a lot. I still have a  QD rear wheel with a drum/sprocket, the rim/spokes are rusty but the hub and sproket are good.

The thread on a Smiths clock apparently  is .460" x 26tpi, I will look for a die and try to modify these crap clocks.  If not I will call Hitchcocks.

What are the best handgrips, None came with the rolling chassis I bought. 1954 Flash ( RGS look-a-like)

Title: Re: Imported speedo/tacho drive thread size.
Post by: JulianS on 29.04. 2021 13:41
The Smiths chronometric head cable thread is metric - M12 x 1mm pitch. Definately not Imperial.
Title: Re: Imported speedo/tacho drive thread size.
Post by: Topdad on 29.04. 2021 13:50
Re the cables why not contact Vernhill , they will make you up a special cable to suit even if you have to send 'em the clocks , Normally these indian ones are enfield and the one they made me as worked well for over 3 yrs and only cost about £15.
Title: Re: Imported speedo/tacho drive thread size.
Post by: MrShifta on 30.04. 2021 12:13
It seems I was expecting an Imperial thread.  You are right it is M12 x 1.0mm pitch and the problem was that the square would not enter the clock enough to allow the thread to connect.  I spent an hour with  a square needle file and managed to get the cables in.

Thanks again for your help.