gearing for sidecar use

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magpie
Posts: 9
Joined: Wed Jan 11, 2017 8:45 am
Location: LINCS UK

gearing for sidecar use

Post by magpie »

HI all
I have a 18s ,but due to a bad hip joint i was unable to ride the ajs 18s
so i got a sidecar fitted,now i find that when i release the clutch the outfit
travels at 10 to 15 mph at engine idle speed.What is the best way to
adjust the gearing? Is there a larger rear sprocket available, or is it
a gear box sprocket change? As i am getting on a bit, the gearbox sprocket
would be a bit of a challenge, but the rear sprocket, i could cope with.
Any help or advice would be much appreciated.
Look forward to any replies.
Regards All

Magpie
zwarts
Posts: 514
Joined: Mon Jan 01, 1990 12:00 am
Location: LANCASHIRE UK

Re: gearing for sidecar use

Post by zwarts »

The usual way to change the gearing for sidecar use is to fit a smaller engine sprocket. The std. engine sprocket for the 18s is 21 teeth. The recommended sprocket for sidecar use is 18 teeth, assuming your bike is pre 1957 (Burman gearbox, not AMC box).. As 18 teeth is the std. 350 solo size, there are plenty of them around. There are no alternative rear sprockets available so the only other way to change the gearing is to fit a smaller gearbox sprocket but that's a much bigger job as it requires the primary drive dismantling and the inner chain case removing etc.
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clive
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Posts: 5657
Joined: Mon Jan 01, 1990 12:00 am
Location: LONDON UK

Re: gearing for sidecar use

Post by clive »

You should be fine with the 18 tooth 350 drive sprocket, but have you ridden a combination before? It's a strange thing and it always seems to want to go somewhere different from you. I recommend carrying a spare set of underwear for your first long journey. :rofl:
clive
if it ain't broke don't fix
magpie
Posts: 9
Joined: Wed Jan 11, 2017 8:45 am
Location: LINCS UK

Re: gearing for sidecar use

Post by magpie »

HI zwarts &Clive
Thanks for your reply,The engine sprocket change is more logical
and far less daunting than the gearbox sprocket. The 18s is a1952
and you say that the 16m sprocket will fit, if so i am at present trying
to purchase a 1951 16ms that may be past the restoration stage
because there are so many parts missing,but would still be good source
of spares.Thanks again.
Regards.
Magpie
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clive
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Joined: Mon Jan 01, 1990 12:00 am
Location: LONDON UK

Re: gearing for sidecar use

Post by clive »

Oh and depending on how worn the front chain is you may need to change it when you go to the smaller front sprocket. 500 chains have 67 links 350 only 66. It may mean shifting the gearbox to adjust and of course then the rear chain.
clive
if it ain't broke don't fix
magpie
Posts: 9
Joined: Wed Jan 11, 2017 8:45 am
Location: LINCS UK

Re: gearing for sidecar use

Post by magpie »

Thanks again Clive
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