I have an original 1969 MK3 Matador running with a 428 size rear chain. Have ordered a 13 tooth gearbox sprocket, the biggest apparently that will fit with the kick start shaft in place. Is there a smaller rear sprocket available? Am trying to get some where in between stock low gearing and pure road gearing. John

Contact Talon as they will make a sprocket to suit you. Or try that famous Bultaco shop in England. Or just use that auction site, the famous one. 

Hi ukmatador,I use 428 chain on all my bikes,& have a 15 T sprocket on a Lobito plus on 2 Alpinas with no problems. The chain does get a bit close to the kickstart shaft,but does not touch. I use ordinary standard chain,not O ring. I do have a 16 T to put on a bit of a special 326 cc motor,it will fit, but there are other jobs to do first. I have just had a look at my Metralla parts list,& interesting to note the standard fitting is a 17 T. The rear sprocket was a 42 T giving a 2.47 ratio. Those bikes would do about 92 m.p.h. Fast enough for you ? The Matador mk 3,pretty much the same motor,had std: gearing of 15--50 which is a 3.33 ratio,so I think a 46 T rear sprocket would be worth a try. Hope this helps,over to you.......

Well,red face at the  moment. Came to fit the 13 tooth sprocket today and found it already had one! thought it was a 12. So with a 13 front and a 46 rear, which it has. 3.53:1,  (8.4:1 overall) it is just too low geared for general road use. If a 15 tooth sprocket will clear the kick start shaft, 3.1:1 is available. 7.3:1 overall with the primary reduction. Will I notice much of a difference? John 

A change in the front sprocket of one tooth makes a noticeable difference. Two teeth on the front makes a large difference

Thanks for the help guys. There cheap enough to change so will try a 14 tooth. Not looking for a massive change but at the moment 40 mph and its revving  too much for road use. John     

14/52 was standard on the Sherpa. We used to fit a 15 for running around but I don't recall it feeling anything but low in top on the road if that is any guide.

As 2stroke 4stroke says that was the norm I used 15 for trail work and 16 for long roadwork on my M49 and the 325 I had They were quick on standard gearing On 16 you could not pull 5th in town without speeding (30mph)But would sit at 70mph all day easily these used the smaller chain size but the later bikes the chain was bigger as on the 175 I have

You may find that your Matador does not have the usual wide ratios typically specified for Matadors/Alpinas/Lobito/Fronteras etc.

I had one early Matador engine that had much closer ratios from another model.

I geared up my mk3 by increasing the size of the front sprocket. Unfortunately I can't remember the size. Cruises at 55mph no problem.

Very nice looking MK3  bultacosd. 

Nice. I see you have the SD exhaust on yours, mine has the trials type so wont breath as easily. Have fitted a 14 tooth sprocket but waiting for DVLA to send me a registration number so can try it on the road.