Crank pin, axle alignment during rebuild

[DerekAJS30]

I am rebuilding the bottom end and will be replacing the big end bearing and at least one (drive side) axle on my G3Ls. Is it necessary to use a special jig to align the axles when they are assembled?

[SPRIDDLER]

Yes, but it doesn't need to be particularly sophisticated. You will need it to aim for a flywheel run-out of 1 to 2 thou. The recommended factory torque for the nuts is 190 ft/lb so (obviously) you will have be able to hold the assembly securely!
It's not a job for the faint-hearted.
There is a full article on the process in the Archives but I can't find it at the mo.

You don't mention the year but have a look at the workshop manual pages 47 - 50 in the link below.

http://archives.jampot.dk/book/Workshop ... dition.pdf

[g80csp11]

Have you already purchase the BE assembly for the rebuild ?
Alpha bearing are the best you can buy , currently we are evaluating the new Hepolite bearings
PM or email me to discuss in more detail

Peter

[DerekAJS30]

Thanks "Spriddler" and Peter.

Nothing purchased yet. It's a sad story really. The engine i purchased within the pile of parts, looked to be OK. We put an endoscope down the bore before i purchased it and there were rather lovely honing marks and a reasonably clean piston. Having dismantled it, it looks like some time ago the engine was rebuilt but then stored for a very long time with no oil. Condensation got in and the bottom end is a rusty mess. Top end is OK, new valves and guides. Although it looks like it has had a "recent" rebore, i suspect the piston is a second hand one so i'm going back to basics to sort it out properly. I couldn't extract the drive side axle from the casing so i'm waiting in hope that my local engineer can do so when the crank case is heated properly. If not, or he breaks the casing, the project is probably dead, albeit i do have a pair of G80 cases. Fingers crossed.

Peter, are you the Peter at the parts dept? I would like to chat.

[g80csp11]

yes I am , also membership secretary
you can ring me ( missed call on your phone at 17.06 today

[DerekAJS30]

Ps. It's a 1952 engine going into a 1952 frame

[SPRIDDLER]

You may already be aware of this. If you are, apologies, but if you are going to rebuild the bottom end with various new pattern bits or with used bits (eBay etc.) there were changes to the c/case, axles, oil pump etc. Have a look here:

https://www.jampot.com/article_read.asp?id=28

You will also find the parts list helpful to assess the compatibility year by year of new or used parts.
The factory parts lists are here under 'Books'.

http://archives.jampot.dk/