Hitchcocks Forum

Hi all, I'm starting on my next special build, it requires a 32 tooth engine sprocket to gear it up.

The question is, is there enough room in the chain cases to accommodate for such a large sprocket?

Do they make larger engine sprockets, if so who?

Engine 25, clutch 56, gearbox 22, wheel 38, + trials gears.


Thank you for your help.

Ian, our Hosts do up to a 29T in the Accessory Catalogue. There is an Albion (British) clutch basket with 54T that was fitted to some Greeves road racing models which might help your calculations and would fit a Bullet. 32T is going very big, even the Interceptors only just got to this size! (actually early Connies had 33T but that's another story) The cranks are bigger on these models so won't fit, before you ask!
REgards, Mark

Hi Ian. Your new engine sprocket size is intriguing. Unless you have an enormously powerful engine, I would guess you’re fitting a much smaller rear wheel? With a standard 19" wheel, the gearing will give you over 140MPH if the engine is revving at 5500 RPM.

Thank you Mark that answers my question of is there enough room in the cases. Now I have to get a sprocket made up.

I did look into the Greeves clutches but they are well expensive if you can actually get one at all. The last one I saw on eBay went for £300,
something to remember though.

Les, the engine is a 954cc Diesel twin 23 - 25 hp, 3700rpm, 90mph, 136mpg, no turbo (at the moment). The gearbox is a trials box, those gears lower 1st, 2nd & 3rd gears, using big engine and gearbox sprockets will push those three gears just a bit higher (slightly harder to pull away) than normal gearing. But now 4th gear is overdrive.

Yes it's a big gap between 3rd and 4th but this is no problem at all for the big diesel.

Ian,
What chaincases are you going to use? Standard Bullet ones, if so the sprocket will foul on the standard stator mounts. I am doing this at the moment to fit Bullet inner primary to a Meteor. I have had to move the stator mounts out and get new mounts welded in and then make up a spacer ring to mount the standard rotor.Alternative is a Super Meteor or Connie primary cases, I think they all had the bigger stator. Series 1 Inters take the smaller stator so no good to you

Hi Norm, I'll be using Indian Bullet cases. The engine has a stator on the right hand side under the flywheel, which keeps things nice and simple on the primary side. Ha ha, as if anything is simple on my bikes.

Hi Ian
No problems then, just grind the stator mounts off and it will fit no probs. The Meteor has a 33 tooth engine sprocket

Mark,
I haven't looked for a long time but I think the Inter might be a 29 tooth because it clears the Bullet stator mounts

Norm, you're right about the Inter sprocket being 29T, although I didn't say this, what I was trying to do was give some perspective on how big a sprocket a particular motor could pull! As far as I know, no Enfield went bigger than 33T. Ian should note that one sprocket in the primary (the front!) should be an uneven number of teeth with either 54 or 56T clutch basket, this evens out wear on the chain and the diesel will be hard on chains I should think!
REgards, Mark

Thanks for the info.
I thought that it was an old wives tail about the chain.
So how does it wear unevenly?
Yes duplex chains don't last long, I was toying with the idea of using a triplex chain for a bit more strength.