Author Topic: 61 A10 gearing  (Read 1934 times)

Offline Chrisf1

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61 A10 gearing
« on: 12.10. 2008 19:59 »
hi again everyone i have a 61 a10 cum s/rocket cum cafe racer which i am running in so at the moment this is not a problem but it will be when that laborius back breaking task of running in is complete my problem is the gearing i am running a 22 engine sprocket with a std 4 spring clutch and std g/box a 19 g/box sprocket and a 42 rear sprocket in top gear at 3200 rpm i am getting 50-52 mph and all the other gears as soon as i am in i need to change up this is fine while i am running in but when that is done i feel sure the gears will not be tall enough any suggestions thanks chris

Offline Beezageezauk

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Re: 61 A10 gearing
« Reply #1 on: 12.10. 2008 20:48 »
Hi Chris,

I run a bog standard A10GF with standard gearing.  It's been on the road now for eight years and I've always thought that it revved too high and was under geared.  But I ran a B31 for years and wondered if it was just that I was used to the throb of a single which gave the impression of lower revs. 

Anyway, I'll be pulling the A10 engine down over the winter and when I rebuild it I plan on replacing the 21 tooth engine sprocket with a 22 tooth in the hope that it will give me a more comfortable ride with lower revs at my cruising speed.

It will be a good thing for you to be running in and thinking that the bike is low geared.  At least you could fit a 23 tooth engine sprocket at a later date and see how it performs.  I believe that RGS's ran a 23 tooth engine sprocket as standard.

It appears that we are both in a similar position.

Can anyone else on the Forum advise on this??



Online Brian

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Re: 61 A10 gearing
« Reply #2 on: 13.10. 2008 00:06 »
I've played around with different gearing over the years and have come back to standard gearing. I now run all my twins on standard gearing. Gearing up does bring down the revs slightly but if you live in a hilly area or ride in head winds a lot then standard is better. I reckon it is better to have the engine rev slightly higher rather than be under load. Reving them doesnt seem to do any harm, I havent blown one up (yet)!

Gearing is how I came to own my 51' plunger A7. The fellow who had restored it seized it every time he rode it, he had the motor apart several times but couldnt work out what was wrong so sold it. When he sold it to me he told me all about the problems, needless to say the price reflected all this.
When he rebuilt it he bought a new sprocket set but didnt do his research and whoever sold him the sprockets didnt know, or care. They sold him a set up for a A10, 42t rear and 19t front. An A7 should have 46t rear and 18t front so the bike was way over geared. I changed the sprockets and the bike has been going well ever since.

Online groily

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Re: 61 A10 gearing
« Reply #3 on: 13.10. 2008 16:37 »
Guess it depends how many horses you have. I've gone up to 20T on the gearbox sprocket on my bog standard s/arm A10 and it pulls it fine. But I think it would struggle with more, as Brian says, given the heavy westerly prevailing winds in this bit of northern France - and it does sometimes need a good head of steam building up in 3rd. I already have a couple of 'with the wind' bikes - I like the A10 for being able to go both ways!!

Online RichardL

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Re: 61 A10 gearing
« Reply #4 on: 13.10. 2008 17:24 »

Recalling your verbal self portrait, perhaps what you need is riding garb with built-in streamlining. I say this knowing you have a sense of humor that will save me if and when we ever meet.

Plan on signing up for the world-wide 2017 DISTINGUISHED GENTLEMAN'S RIDE on September 30, 2018. Watch website at for details.

Online groily

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Re: 61 A10 gearing
« Reply #5 on: 13.10. 2008 20:32 »
You're right Richard. I have the profile of a lead brick! Love a tail wind and downhill slopes and the flat's OK. . . but suffer otherwise. Especially on the B31, with all its 16bhp.
Guess this thread should be renamed 'how many pounds per tooth can an A7/10 pull'!

Offline snowbeard

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Re: 61 A10 gearing
« Reply #6 on: 15.10. 2008 01:10 »
nice looking bike you've got there!

I've got the scrambles gearbox, 357 cam, and who knows what for pistons (haven't been that far in yet) but I'm running a 21 tooth engine gear, 43 tooth clutch sprocket, 19 tooth drive gear and 46 tooth on my rear sprocket and have been told this is standard kit for an A10, and that at this gearing it should push rpm's of 4200 @ 65 mph and 6400 @ 100 mph.

I don't have any guages so I couldn't tell you if I do, but that's what I've been told by others ;)

\'57 BSA A-10 Spitfire Scrambler
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Offline A10Boy

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Re: 61 A10 gearing
« Reply #7 on: 17.10. 2008 12:08 »
Hi, you ask for suggestions, well heres one - Sell your bike to me....

Seriously, arent there two std gearings for the Golden Flash, one for sidecar us and one for solo ?

Mine seems to rev too high, and that was attached top a sidecar when it was new. I am going to take a look over the winter, maybe gear it up a bit.


1960 A10 - Black Golden Flash
1974 Kawasaki Z1a
Yam XJR 1300