WANTED - BAP speedometer driven gear

SteveShone
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WANTED - BAP speedometer driven gear

Post by SteveShone »

As per my posting in the 4-stroke section
viewtopic.php?t=13282
Im on the lookout for a speedometer driven gear for my BAP gear box. It's a 16 tooth variant - I understand that these may have changed over the years which would only add to the grief ;) My box has the serial number XI BAPDH 55863 if that helps - so far I have not been able to find a website/information that would allow me to date it
Ariel speedo drive.jpg
Thanks. Steve
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Re: WANTED - BAP speedometer driven gear

Post by will_curry »

I think your best bet will be to contact the club's gearbox spares man Geoff Brown whose
details are inside the front cover of Cheval.

I've just read your other post. You're ahead of me.
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Roger Gwynn
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Re: WANTED - BAP speedometer driven gear

Post by Roger Gwynn »

Your gearbox number denotes a BA gearbox from pre war but with a sprocket oil seal, basic version.
The 16T speedo gear is 3150-47, used with Chronometric speedos 1947-49 when it was replaced by 3150-50 with 15T to correct an incorrect ratio 1950-52. Your gearbox would have used a PA speedo and a gear with 15T 3150-31 1931-46. Yes there are 2 gears with 15T but they are not interchangeable, the later one has a groove machined into the shaft to differentiate it. The matching layshafts are 11T 1934-46, 8T 1947-49 and 7T 1950-52.
Roger Gwynn, Membership Secretary, curator of the Machine Register and the works drawings. Director of Draganfly Motorcycles, Craven Equipment and Supreme Motorcycles mostly retired.
SteveShone
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Re: WANTED - BAP speedometer driven gear

Post by SteveShone »

Thanks for the info, Roger. I had a feeling that problems were afoot and nothing is simple :shock: I vaguely recall reading somewhere that the X denoted an oil seal but haven't been able to find where it was :oops: Aint age wonderful?

Steve
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john.nash
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Re: WANTED - BAP speedometer driven gear

Post by john.nash »

I fitted the kit from gearbox spares.

Carefully reduced the shaft down, on the lathe, to get a tight intererence fit for the new end. Not sure you can do it, without a lathe.

I think my box was originally PA as well.
John Nash
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''78 t140 bonneville, '77 BMW R80, '67 CJ750, 196-ish Ural M62 outfit, '51 VH500, '49 project Ariel , '47 VH twinport, '44 Ariel WNG, '42 indian 741b, '41 Ariel WNG and piles of rusty scrap ....
SteveShone
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Re: WANTED - BAP speedometer driven gear

Post by SteveShone »

Thanks, John. Ive been in touch with Geoff about it and it could be a little engineering adventure with the Boxford is on the cards. Stripping the box wasn't my first choice - Ive done it a few times on my 37 Sunbeam which had a noisy BAP box (but no speedo drive) I cured that eventually and at a price, but it was the mess created by a grease filled box that was the real turn-off!

Steve
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paul.jameson
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Re: WANTED - BAP speedometer driven gear

Post by paul.jameson »

Your gearbox is 1938, almost certainly, with a very small possibility of early 1939. It is only during the past year or so that we have been able to date these gearboxes at all and we are not yet at a point where we have enough data to give a more accurate date.
Paul Jameson
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Re: WANTED - BAP speedometer driven gear

Post by SteveShone »

That's interesting, Paul, thanks. I have a dating certificate from 1990 that confirms that the bike, originally an NH350, was despatched on 26/5/37 and the old brown RF60 shows the date of registration as 25/6/37. It now has a 500 OHV engine, the dating certificate for that shows that it was despatched as a complete machine to the Air Ministry on 13/5/40.
There are no gearbox numbers recorded on the dating certificates. Perhaps the gearbox in it now came with the 500 engine - and the sidecar it was bolted to in the late 40s. It's had a colourful past. I got the tank back on today and mounted correctly after making fresh spacers and new rubber washers - ie the bars no longer contact the tank top panel on full lock and Ive got clearance above the rocker cover bolts - which is a bonus.
The only job left to do is to check over the dynamo. I don't know whether it is giving an output yet but having spent a fair amount of brass over the years rebuilding them on various bikes, I'm more minded nowadays just to run the electrics as a total loss. With LED bulbs and vitually no horn use (who'd hear the thing above the exhaust note anyway?) a charged battery will last an age :)

Steve
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paul.jameson
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Re: WANTED - BAP speedometer driven gear

Post by paul.jameson »

Reading both of your posts several times, I suspect that you may have more modifications than meet the eye. If your speedo is a chronometric one, you need different gearing for it from the original PA type. To fit that different gearing in a prewar gearbox is possible, if you know what you are doing, but it does confuse subsequent owners no end. Another difference between the two speedo types is that the speedo cable connects to the bottom of the chronometric but to the side of the PA. This of course makes for totally different routes through the petrol tank for the speedo cable and hence to different petrol tanks, although they look just the same at a glance.

It is all part of the history of the bike and a tribute to the interchangeability of Ariel parts. I have a 1937 RH500. When I first knew it, the engine was 500cc with petrol and oil tanks to match. Then a 350cc engine was fitted and I ran it like that for many years, with the small petrol and oil tanks. It is now back to 500cc with large petrol and oil tanks. But I originally bought the bike to fit a 600cc OHC Square Four engine into it. That project got abandoned but I did eventually fit an OHC four engine into what was originally a VB. But whatever engine you have, they are great bikes to ride and use.
Paul Jameson
35 LG (project), 37 RH500, 52 ex ISDT KHA, 54 KH(A), 75 Healey 1000/4.
Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser (over a 25 year period).
Now Archivist (but not Machine Registrar), Gauges and Clocks Spares Organiser.
SteveShone
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Re: WANTED - BAP speedometer driven gear - AN UPDATE

Post by SteveShone »

I must admit to feeling a little despondent when I read your post, Paul. I had visions of all sorts of mayhem and aggravation being uncovered. However, the Spirit of Ariel has decided to grant me a respite.
Geoff Brown of gearbox spares fame was extremely helpful and sent me a speedometer drive kit as promised. When it arrived I was able to compare it with what I have. My layshaft has an 11 tooth worm gear which measured up exactly the same as the new sleeve gear. I also found that the new 15 tooth speedo drive spindle meshed properly with the layshaft as it did with the new gear of course. All this got me wondering whether the 16 tooth spindle was yet another bodge job and it would account for the wear pattern on its surviving teeth.
With nothing to lose by trying it I loosely assembled the gearbox outer case and found that the speedo drive operated perfectly. That was all the encouragement I needed to put the old girl back together.
The new 35 inch speedo cable fitted without a problem and fed up through the tank to meet the chronometric speedo with any strain on the bends. Letting the bike run a slightly fast tick over in top on its stand, the speedo was showing a steady 25 which looks promising. Of course I didn't expect things to turn out so well this weekend so I didn't insure the bike on Friday - Im now pacing until Monday when I can get it on the road for a proper try out and find out how accurate or not the speedo is.
Can I express my thanks to all those who readily provided the above information and suggestions (and spares of course) which has definitiely increased my knowledge of Ariels. I'll know at least some of the things to look out for when I get the next one ;)

Cheers. Steve
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