Am I bushed or just plain knackered? G80/M18

[Mckorkins]

Quite right, Alan! Of course I won't botch the actual job and will see to it that things are done in the proper manner. Once it has been replaced, I might fiddle about and try and repair the the old timing side crankcase as an experiment only and use it as a spare if it turn out OK. If not, it's going for recycling! In fact I think that I might enjoy doing this work, as you certainly can't ride the Ajay in this weather we're having! Regarding the maths part, I just wanted to be certain that my calculations on measuring wear/play were done in the right manner and I'm now much clearer on this aspect thanks to the help I've received on this subject.

Thanks for your responses too. All helpful.

Cheers

Mac

[alanengineer]

what you did with the two photos was first class. It make things so easy for us to understand. Do it again and you will get more sensible answers.

[iandusud]

When I rebuilt my G3LS engine I found all the wear to be on the axle rather than the bush. Seeing as you will be replacing the axle it would be best to wait until you've fitted it and then recheck for play. I know it sounds counterintuitive that that a steel shaft should wear in a bronze bush but I have seen this also on swinging arm bearings.

Ian

[Tolly]

If you are going to renew one it is wise to also renew the bush.

[Mckorkins]

Alan, Ian & Tolly - thanks for your remarks, which are both encouraging and sensible. I'll definitely renew the bush - even in the 'new' crankcase half, so at least I'll know that and the axle are perfectly matched. I will renew the main bearing on the drive side as well. Goodness knows what the piston and bore are like. I suspect they're OK, as the engine has done so few hundred miles since it was rebuilt - but if any of those metal filings have gone walkabout, it may be a different matter entirely. Come to think of it, I've noticed that there has been a build-up of filings on the magnetic plug when changing the oil (regularly), but I put that down to the engine bedding in a bit. Now I'm not so sure! Anyway, due to other activities, I shan't be getting around to doing any more work on the old bike for a month or so. I've flagged up to Hamlins of Bridgwater to expect some bits to work on then!

Tolly, have you discovered if we are related by marriage yet? A person contacted me through Ancestry the other day and it turned out that she was 4th cousin to my wife on the Tolhurst side (Kent/area), so there's still a very good chance that we are! Sometime it would be interesting to compare family trees, if that's possible. I can send a link to ours on Ancestry.com via a pm, if you're interested.

[alanengineer]

when you have the engine apart, it might be an idea to check the crankshaft has been assembled in line. just a thought. dont trust other peoples ability, even if you dont trust yours yet.

[Mckorkins]

That'll be done by Hamlins, although I'd happily give it a bash (I'd probably end up with a real thumper that'll buck me out of the saddle!).

As it isn't 100% sharp, I wasn't going to post this pic that shows the dial-gauge rig, but for what it's worth here goes: