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General => Douglas Motorcycles - General Discussion => Topic started by: hoejmark on 13 Aug 2021 at 09:26

Title: G31 sprockets
Post by: hoejmark on 13 Aug 2021 at 09:26
From a great motorcycle museum here in Denmark I have been asked about the correct sprocket sizees for a G31 they are going to restore.

Frame No. Ed 180 (I believe should be FD 180) and Engine No. EU 139.

They ask for the sprocket size on the rear wheel and on the gear box (present is 59T)

From the Machine Register I can see that this bike must be very rare, and we used to have another one here in denmark (Frame FD178, Eng. EV113 (should be EU113?)), that I don't know where is now.

Can someone help with information.

Regards
Hoejmark


Title: Re: G31 sprockets
Post by: Daren W Australia on 13 Aug 2021 at 09:58
Hi Hoejmark

Try www.buyoldengineering.com scroll down to Douglas they might be able to help

Ta Daren
Title: Re: G31 sprockets
Post by: hoejmark on 13 Aug 2021 at 16:05
Thanks Daren

I will have a look at the site.

hoejmark
Title: Re: G31 sprockets
Post by: hoejmark on 27 Aug 2021 at 11:51
Hi again

The BuyOld Engineering doesn't have sprockets or know sprockets data for the G31/32.

Is there a helpful guy out there who can have a look into the Spare Parts List or similar booklet dealing with G31/32 to find these data as I have no booklets myself dealing with OHV models.

Hoejmark
Title: Re: G31 sprockets
Post by: Doug on 28 Aug 2021 at 05:24
I have never seen or heard tell of a spares list or manual for the 1931-32 or the 1934-34 ohv models. If there was one, I would certainly like to see it too! So I think you will need to look at the few surviving examples and try to count sprocket teeth. I do have some F/G31 pics, but I am on the road at the moment and do not have access to them. It is not a common model and info on them is quite scarce.

-Doug
Title: Re: G31 sprockets
Post by: eddie on 28 Aug 2021 at 07:56
The publicity sheets for the F/G31 didn't give any details of the gear ratios, but the later sheets for the OW1 (with a 4 speed 'box) gave the ratios as 4.4, 5.8, 7.56, 12.7. If you aimed for a 4.4 ratio in top gear, you shouldn't be very far out.

  Regards,
               Eddie.
Title: Re: G31 sprockets
Post by: hoejmark on 29 Aug 2021 at 17:19
To Dave and Eddie
Thanks for your replies and I understand, that the G31 is a rare model making it difficult to find informations.

However I managed to find a photo in a therad from alex912, where i am able count 18T on the rear chains gear box sprocket.
Thats a beginning,  together  with aiming for a ratio of 4.4 in top gear.

Regards
Hoejmark