C15 Bearing Updates

Started by Ian T, 11 Dec, 2025, 10:17

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Ian T

Hi everyone

I've been doing lots of reading etc and as also kindly mentioned by Stubaker58 that the G suffix is the better engine I presume because of the bottom end upgrades over the production run.

Could I ask please, with the earlier engines are the updated bearing easy to obtain and fit. I recall upgrading a Norton Commmando once and in the end I sent casings of to SRM I think it was for their needle roller conversion.

I suppose what I am asking in my roundabout way, with and older engine is, is it worth upgrading and can a man with three hammers do it.  :o

Also please, I've used Boyer electronic ignition on a couple of older bikes in the past, and mighty fine they were. If I am going this way would the Boyer suffice or in your opinions is it better to go the whole hog and convert to 12volts.

As always

Cheers

Ian

Or am I overthinking it all as usual

rhyatt

The early C15s and other twins had plain bush timing side bearings.
My 2 C15s run well with this original set up ,given our usage and oil change routines , I personally would stay there.
The big end on earlier C15s were plain bush running on a plain crankpin and perhaps the same philosophy may apply to that.
The big end can be converted to roller by any decent engineer.

12v , utterly simple to achieve conversion from original 6v and makes life easier , but I run all my bikes on their points set up , the only exception is my bantam that I use an electronic kit to help the points . Cheap and easy to fix.

I've always visited my local bearing factor for bearings , 12 quid for decent British main bearing and 7 quid for decent British Xbox bearing

Ian T

#2
Brilliant and thanks.

Best leave well alone then, which is good as it does open up all the years for me.

I'm certainly no engineer let alone a decent one 8)

Good to know on the electrics front also.

Suppose I better get looking now.

Really appreciate your replies.

Cheers

Ian