SLOPER SPROCKET PROBLEMS

[mark quinney]

Hi all  I brought  a 1930 493cc OHV sloper in bit's awhile back and as a dry run have slowly been putting it back together to see if all the parts are there and  what bits are missing or in need of repair etc , so my question is -
1    I have a new rear wheel sprocket and a gearbox sprocket both came with the bike  The gearbox sprocket has the correct 22 teeth  and is 3/8 of an inch thick  The rear wheel sprocket is the correct 42 teeth but is only 1/4  of an inch thick I would have expected this  also to be 3/8 of an inch thick so there is no side play on the chain when in use . So my question is  which one is the correct thickness or is it possible they are both correct ?  .  Would running the bike with these different thickness  sprockets cause any problems or be  dangerous in the limited amount of mileage it will be doing .  I look forward to receiving your thoughts regards Mark

[mark quinney]

 Sorry in previous post I meant to put 19 tooth gearbox sprocket So if anyone has any ideas please let me know regards Mark

[idie]

If it's any help.  I have been running my B33 with a 3/8 inch gearbox sprocket and the rear 1/4 inch for years with no problems.

[mark quinney]

Hi Idie
Thank you for your reply it is of a lot of help knowing that it can be done and has been working successfully on yours for years, it also saves me having to look around trying to source difficult to find  parts so thank you again for replying regards Mark

[idie]

You're welcome.

[Y13 Alan G]

Hi Mark. according to my 1929 BSA catalogue the front chain is 1/2 inch x .305 inch and the rear chain is 5/8ths x 3/8ths inch.
hope this helps. Alan

[mark quinney]

Hi Alan
Thank you for the reply would appear then that the 3/8 gearbox sprocket is the right thickness  ,which would mean that I've got to buy a new rear wheel sprocket or have one made  which is more difficult than it sounds as no one I've tried stocks them and I've contacted several sprocket places but no one wants to make dished sprockets . At present the bikes nowhere near ready for the road so hopefully one may turn up in the near future regards Mark

[BEVANC]

Hi Mark,
It is possible to machine off the teeth and attach a ring from a donor sprocket. I am expecting to have to do this as my sprocket has 46 teeth, whereas it should be 42. A Sloper owner here in N Z. has done this recently. I could ask what donor sprocket he used if you like. Cheers, Bevan

[mark quinney]

 Hi Bevan
Yes please if you could contact the sloper owner as it would be interesting to know what he  used . I'm going to  an engineering company later this week  to see how much it would cost to have a new sprocket made assuming they can do it .  There is a person in Australia making them and selling them on eBay so that might be a possibility but  there not advertising at the moment so will keep an eye out  regards Mark

[BEVANC]

Hi Mark,
If you are in the U.K., this posting off an Ariel forum might be of interest:

"i use B & C EXPRESS they are very good we have had lots of sprockets made by them with different pitches for a lot of rat bikes we build their phone number is 01522 791369 give them a ring and they will help you and make them for you they was the makers for sprockets unlimited be for he sadly died"

Cheers, Bevan

[mark quinney]

 Hi Bevan
I am in The UK , thank you for forwarding the post from the Ariel forum i will be phoning them on Monday to see if they can help me out , I will let you know how i get on regards Mark

[BEVANC]

These Australian guys make them too: http://www.buyoldengineering.com/
Cheers, Bevan

[mark quinney]

Hi Bevan
Thank you for forwarding the link to the sprocket company I saw  them  on eBay a while back with postage it starts to get a bit expensive but if I can't get one sorted in the UK I'll be ordering one from them in the near future , though I'm not in a great rush as I've still got to rebuild the engine ,  get the forks overhauled ,fit new wheel bearings spokes tyres etc , headstock bearings , rewire it plus lots of other jobs though it will be nice to get it back to being a rolling chassis instead of lots of bits all over the garage , hopefully will have it ready for next summer when /if we're allowed out regards Mark

[Paul.W]

I had a similar problem, in that I have a 350cc Sloper and it had the 500cc rear sprocket which meant it was way over-geared.
Like you I didn't fancy having a new sprocket made, but I managed to identify a much simpler solution.  I bought a modern  one from this outfit;

https://www.wemoto.com/

I needed a 48 tooth sprocket so I found this this;

https://www.wemoto.com/parts/picture/bj-jtr-472x48   

It is flat and not dished, but it was very  easy to machine up a carrier in aluminium that was the correct thickness that bolted on to the rear hub in place of the original sprocket and had a register to take the new one.  If you don't have the machining facilities any small machine shop will turn one up for I would think not a lot of money.  It is designed for a 1/4" chain and not 3/8" but I haven't found that to be a problem either.  Once painted black and fitted it is completely unobtrusive.

There are hundreds of sprockets listed on their site, its just a matter of looking though them to find something suitable.

[mark quinney]

 Hi Paul thank you for your post ,  I took my sprocket to an engineering company on Friday who are looking at making me a new one so I'm just waiting for them to get back to me and let me know if it's viable or not If not I may well go down the same line as yourself I had a look at the website  you recommended and they sure stock a lot of sprockets  so won't be a problem sorting one , will let you know how I get on regards Mark