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« on: February 09, 2020, 02:49:31 PM »
Hello all.
Sorry for disappearing on you all late last year. I have been flat out clearing my Callander ready to attack the rebuild.
I am pleased to report that I have now got my teeth well into the rebuild and thought it was time I gave you all an update on my progress so far.
Since my last posts, I have spent many an evening researching and violating parts and knowledge from friends and the beloved you tube.
I now have the crankcase split and have retrieved the cam chain guide which appears to have been the initial offending part that caused the cam chain to break in the first place. In 600 miles since the previous owner had done a “top end” rebuild. The cam chain had been orb completely through the guide face and then right through the steel backing, getting caught on the backing and subsequently breaking the chain. Lucky for me, as the engine had only been running for a short time under these conditions it has not done a huge amount of damage. The big end and main bearing are caked in steel particles from the guide and are no good, but this has not damaged the journals.
So. After this investigation, I have now a big long list of parts on the way for the rebuild. Luckily I only needed one pair of A bearings (the rare and elusive A bearing) my local engineer shop has measured the crank and has said a B bearing still brings me within clearance.
I have had the top and bottom end vapour blasted and some of the covers, I’ve also made a couple of repairs to the bore fins and painted the block. Whilst in the bottom end I’ve found the reason for poor fifth gear selection. Worn main shift fork. I’ve sourced all new bearings apart from three which are no longer available and again, luckily. These three are still good in the original, so will be going back in along with a multitude of new parts. David Silver and CMSNL have both done very well out of me over the past few months.
I have spent hours cleaning up parts and polishing out some slight corrosion on some parts in the bottom end. It seems this bike may have been say for a while at some point in its life. A few parts like the shift drum had some minor pitting and the shift fork spindle. So out came the polishing paste’s and away I went.
So enough of my waffle. Here are some pics for your rainy days.