When we stripped the engine down, we had noted that there was a lot of play in the big end, so stripped the crank down completely, de-sludged, then dropped it round to an old boy for assembly and balancing. We don't have the right tools to do this ourselves, so the expertise of someone that knows was definitely the best option here.
Something my Dad and I have talked about a lot as we have been doing this project is that people with these old-school skills are fading away.
There are lots of old men in sheds that have so much knowledge and skills with these old bikes, and their businesses are not being continued as they get too old to work, and retire.
It's such a shame!
Don't get me wrong - I love modern engineering, and use it wherever I can.
But there is always a place for a man in a garden shed who has mastered his trade over the last fifty years!
As you can see, the crank was in a bit of a mess.
So we drove out the old small end bush, and pressed in a new one (with lots of heat)
The new bush was nicely scrolled, whereas the old one was plain, so hopefully the scrolling will keep a nice layer of oil between the surfaces and wear better than the old one did!
Double checked the fit of the piston gudgeon pin (wrist pin) it was perfectly snug with no play.
Then we gave the conrod a good polish, and got out some of the marks left in it from last time the engine was 'overhauled'
Next up we did a few trial fits of the crank in the cases, and tested the end float.
It took three attempts with different shims and a dial test indicator until we got it spot on.
With the right shims on the crankshaft, a smear of Loctite bearing retainer and fitting of the main bearings was next.
The Loctite dries anaerobically (ie, by excluding the air around it) so a quick wave of a flame around it sets it up straight away, so you don't need to wait for it to set up.
