The BSA A7-A10 Forum

Technical => Frame => Topic started by: Minto on 20.04. 2019 10:50

Title: Speedos
Post by: Minto on 20.04. 2019 10:50
Speedos. No, not a picture of me in my budgie smugglers!
I was out yesterday for a proper ride for the first time since I got the bike, did about 80 or 90 miles I reckon. The bike ran lovely and really is a joy. The only fault that occurred was on my way home, the speedo started acting up. I'm used to the needle moving in 5mph increments and understand that's how these chronometrics operate, but for about 1/2 mile the needle was jumping between 30 to 60 mph, then it stopped and behaved itself for the rest of the journey, another 6 or so miles. Is this a sign of it needing attention or just a Smiths foible?
What a cracking day. Had so much fun I forgot to take any pictures. Doh!
Thanks all
Title: Re: Speedos
Post by: Triton Thrasher on 20.04. 2019 11:37
A kink or a sticky bit in the cable?
Title: Re: Speedos
Post by: lawnmowerman on 20.04. 2019 11:50
Speedo may need a strip and clean - possibly a dead spider in there. My speedo used to go slowly up to maximum and then back to zero when stationary. A clean and lube by a local expert at the bike club fixed it.

Title: Re: Speedos
Post by: Bsareg on 20.04. 2019 13:25
Sounds like either the little clutch inside is slipping or the escapment wheel is sticking. Old oil causes both.
Title: Re: Speedos
Post by: Rex on 20.04. 2019 18:19
I wish I knew what bits to clean (or avoid!) to remedy this age-old Chrono problem.
Title: Re: Speedos
Post by: wortluck on 20.04. 2019 20:46
Greetings.  I had mine refurbed by that nice man in Northants (forgot his name again).  It works great except for the trip meter which occasionally decides to turn the x10 wheel x2 times (if you see what I mean) - so 19 miles suddenly turns over to 40 miles instead of 20.  Not too worried as the odometer is correct.  As for jumping, mine goes up a little jerkily up to about 65 then decides that it's reluctant to move any further.  A quick blip of the throttle will see it jump from 65 to 75 then it gets nervous and retreats again.  Vagaries of old Smiths equipment I suppose. ;)
Title: Re: Speedos
Post by: UncleD on 20.04. 2019 22:53
I wish I knew what bits to clean (or avoid!) to remedy this age-old Chrono problem.

There is an excellent Smiths Chronometric Facebook page with plenty of info and helpful people. 

It's not difficult to strip and clean the just have to get over the fear of opening it up!  Basically remove the mechanism and soak in kero or alcohol...and then a very light oil of moving parts.
Title: Re: Speedos
Post by: ellis on 21.04. 2019 09:11

The man you need is

Mr Russell Smalley of Chronometric Instrument Services in Nottingham.
Unit 21b
The Sherbrook Business Centre
Sherbrook Road,
Tel +44 (0) 115 9206156

He will give you the best service at a very reasonable rate.

Title: Re: Speedos
Post by: wortluck on 21.04. 2019 18:23
Sorry, Notts not Northants, apologies Russell.  I opened one up once to strip and clean, screwed the whole thing up.  Guess if you have the time and are patient, it's ok, otherwise just pay Russell.