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August 29, 2019
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Hi All
I've been preparing the wheels of my 1966 D7 to be powder coated and I'm at the point where I'm looking to order a new rear wheel sprocket, (along with the wheel bearings etc.). I've decided to go down the original chain size route, (rather than a 420 metric chain), and therefore I need an 8 hole, 47 tooth sprocket. Searching on-line has thrown up some surprising results on sprocket prices. I've seen a rear sprocket on Ebay for £13 and on other BSA parts trader sites for £20, £35 and up to £48 including the VAT.
My first thoughts are the cheap ones will probably be cheap imported ones and could be quite soft and wear quickly. The expensive ones seem to advertise 'British made' and you would hope are of good quality.
What have other people bought for their restorations?
Are the cheap ones with looking at or best to steer clear?
Cheers
Highfield
February 7, 2013
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Hi Highfield
Either stick to an imperial or metric chain and sprocket set, do not mix, the chain rollers are a different diameters. Since SpacedMarine raised the question of gearing read on for my saga.......
I have a B175 and when I striped the engine for a rebuild the final drive gearbox sprocket was 14 teeth and slightly hooked? Looking at the Hayne's workshop manual it should be 16 teeth which, according to Hayne's, is the same as the last D7's. My thoughts were the B175 produces almost twice the power of the D7 (don't know about the torque) so why not higher the overall gearing. This was not to give me a higher top speed but, easier crusing. Did a bit of digging around, and if my memory serves me correctly (it was just over a year ago) I bought a 17 tooth sprocket from Sprockets Unlimited, Evesham way. The sprocket was for the imperial size of chain. My rear sprocket was OK.
Just for SpacedMarine, I can't say whether there is any difference as yet since Iv'e only done 250 miles since I got my B175 on the road last year and then........ the heavens opened up!
B175, on the road. Honda XBR 500, and ....... Suzuki Burgman 200 scoot! Nicknamed "The hair dryer" - by me I hasten to add; & great storage under the seat when you get to your destination.
January 18, 2020
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I've just ordered a D1 one from Bournemouth Bantams, £35. Draganfly, same, out of stock. Classic Bike Shop, 15 quid -ish, but something about comparing the photos suggests the dearer ones are better. I agree it shouldn't get a lot of force on it and therefore wear, in my case a whole 4 hp, (if I'm lucky!) but I thought, meh, least should be right.
BTW what do peeps use for nuts and bolts?
Mike H --
Murphy's 4th law of motion states that any small object that is accidentally dropped will immediately hide itself under a larger object.
September 28, 2011
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Number6 said
I've just ordered a D1 one from Bournemouth Bantams, £35. Draganfly, same, out of stock. Classic Bike Shop, 15 quid -ish, but something about comparing the photos suggests the dearer ones are better. I agree it shouldn't get a lot of force on it and therefore wear, in my case a whole 4 hp, (if I'm lucky!) but I thought, meh, least should be right.BTW what do peeps use for nuts and bolts?
Number6, I think I used M5 socket screws,washers and nylok nuts.
Dougie;Glasgow ;Scotland.
1955 D1, 1970 B175
January 18, 2020
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Ah wondered if M5 would fit, thanks. 
Whether I'll receive it now is something else! 
Mike H --
Murphy's 4th law of motion states that any small object that is accidentally dropped will immediately hide itself under a larger object.
April 29, 2019
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Hi Number6 use bolts not set screws , not threaded all the way down so the straight shank is located in the holes.
Frank
February 24, 2015
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not henpecked said
Hi HighfieldEither stick to an imperial or metric chain and sprocket set, do not mix, the chain rollers are a different diameters. Since SpacedMarine raised the question of gearing read on for my saga.......
I have a B175 and when I striped the engine for a rebuild the final drive gearbox sprocket was 14 teeth and slightly hooked? Looking at the Hayne's workshop manual it should be 16 teeth which, according to Hayne's, is the same as the last D7's. My thoughts were the B175 produces almost twice the power of the D7 (don't know about the torque) so why not higher the overall gearing. This was not to give me a higher top speed but, easier crusing. Did a bit of digging around, and if my memory serves me correctly (it was just over a year ago) I bought a 17 tooth sprocket from Sprockets Unlimited, Evesham way. The sprocket was for the imperial size of chain. My rear sprocket was OK.
Just for SpacedMarine, I can't say whether there is any difference as yet since Iv'e only done 250 miles since I got my B175 on the road last year and then........ the heavens opened up!
I have a B175...I am around 100kg...but if I upped the gearing on my B175 it maybe to tall the 4th gear....std gearing at present.
My Bantam video https://www.you.....jpOFmzRZRI
December 24, 2016
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With regard to the fixing bolts, anyone know where to find replacement 7/32 x 5/8 CEI (Reduced Hex) ones. Dragonfly out of stock (90-6241) and I have one sheared off that I would like to replace. Thanks.
Ed.
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