Re: Kick Start Return spring
Posted by Chris Exelby on Apr 05, 2021; 2:28pm
URL: http://silk-motorcycles.221.s1.nabble.com/Kick-Start-Return-spring-tp5002147p5002156.html
Ok. Removing the gearbox end plate was straightforward. The small circlip holding the layshaft into the bearing actually fell out as it was not engaged! The Sprag gear was a little worn, it seems ok as you can see in the photo but any advice appreciated.
The mating cog on the shaft also seems ok as you can see in the photo.
There was evidence of some rubbing on the gearbox end case (on the inside) where the sprag gear had caught. This gearbox is an earlier one (bike number 46, engine 48) and the bearing is bronze bush (not the later roller bearing) and when mated with the shaft there was play in the bearing as the result of lots of kickstart activity due to poor starting!
Hypothesis is that when the kickstart was tightened up to make it more usable, the additional torque on the shaft caused it to flex which led to contact between the sprag and the gearbox end plate. So to restore the action to that of a firm action I will replace the bronze bush. I understand that the bronze bearing is a Caro bronze se46 and any help finding a source would be appreciated. Google would indicate its the same one as fitted to the gudgeon pin on the piston? Getting the old one out might be difficult and I might take it to a machine shop, recommendations welcomed! Based in Hungerford in Berkshire.
I have an MGB which I use for endurance rallying and also a Norton Commando 850, so I am used to belt and braces British engineering!
URL: http://silk-motorcycles.221.s1.nabble.com/Kick-Start-Return-spring-tp5002147p5002156.html
Ok. Removing the gearbox end plate was straightforward. The small circlip holding the layshaft into the bearing actually fell out as it was not engaged! The Sprag gear was a little worn, it seems ok as you can see in the photo but any advice appreciated.
The mating cog on the shaft also seems ok as you can see in the photo.
There was evidence of some rubbing on the gearbox end case (on the inside) where the sprag gear had caught. This gearbox is an earlier one (bike number 46, engine 48) and the bearing is bronze bush (not the later roller bearing) and when mated with the shaft there was play in the bearing as the result of lots of kickstart activity due to poor starting!
Hypothesis is that when the kickstart was tightened up to make it more usable, the additional torque on the shaft caused it to flex which led to contact between the sprag and the gearbox end plate. So to restore the action to that of a firm action I will replace the bronze bush. I understand that the bronze bearing is a Caro bronze se46 and any help finding a source would be appreciated. Google would indicate its the same one as fitted to the gudgeon pin on the piston? Getting the old one out might be difficult and I might take it to a machine shop, recommendations welcomed! Based in Hungerford in Berkshire.
I have an MGB which I use for endurance rallying and also a Norton Commando 850, so I am used to belt and braces British engineering!
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