Resurrection of a wreck

John Watson · Post by **John Watson** » Sat Oct 28, 2017 2:20 pm

Just a quick update, the motor is gradually coming apart, should split the crankcase halves this week sometime. I'm now looking for a gear change cross shaft, the splines were totally goosed when I finally removed the gear pedal and when I removed the camshaft, one of the advance/retard springs was quite loose and looks as though it's been stretched at some time. I doubt I will be able to get my hands on a spring so it may well come down to a complete replacement mechanism.

AlanW · Post by **AlanW** » Sat Oct 28, 2017 4:37 pm

Hi John,
David Silver usually has advance springs.

John Watson · Post by **John Watson** » Sat Oct 28, 2017 5:28 pm

Thanks, Alan, I'll give them a try.

John Watson · Post by **John Watson** » Wed Nov 08, 2017 8:45 am

I checked with Silvers, Alan, but they have none at the moment. I did, however, come across a cylinder head on UK Ebay that was quite modestly priced, so I bought it. It came complete with valves, springs and the all-important advance and retard mechanism fitted to the cam sprocket. Bearing in mind that I not only need the governor spring but also at least one valve, I figured that after satisfying my needs, the rest could be sold off on the bay.

I split the crankcase halves a few days ago and have spent a few hours cleaning up all the bits and pieces that go to make up the engine, before inspecting the component part more closely. I made up a rough stand for the engine so I wouldn't rest the weight of the motor mon the cylinder studs.

PB076221 by Happy Grandad2010, on Flickr

There is a noticeable scuff in one of the cylinder walls, presumably where the LH piston crown broke up, enough to require a rebore. Silvers only have .75mm oversize pistons in stock so I guess that's the way to go. I'll take a run out to my local friendly engineering company tomorrow and take their advise before I do anything.

The engine internals, apart from the issues already identified, seem in good order, I was particularly pleased to see that there was no discernable wear on the gear dogs.

PB076222 by Happy Grandad2010, on Flickr

It is fairly common knowledge that acids are produced during combustion which are held in the oil, not so much a problem in an engine left standing for a year or two, but when ferrous objects are left soaking for a couple of decades, this can be the result:

PB016205 by Happy Grandad2010, on Flickr

More to follow as and when there I decide to brave my rather chilly, unheated, workshop.

G-Man · Post by **G-Man** » Wed Nov 08, 2017 9:50 am

John

I may be able to come up with the gear shaft. You should also look carefully at the kickstarter shaft that goes through the countershaft. Take a good look at where the crowded rollers run on the shaft. I have new rollers if you need them.

Back in UK tomorrow.

G

John Watson wrote:Just a quick update, the motor is gradually coming apart, should split the crankcase halves this week sometime. I'm now looking for a gear change cross shaft, the splines were totally goosed when I finally removed the gear pedal and when I removed the camshaft, one of the advance/retard springs was quite loose and looks as though it's been stretched at some time. I doubt I will be able to get my hands on a spring so it may well come down to a complete replacement mechanism.

John Watson · Post by **John Watson** » Wed Nov 08, 2017 10:20 am

Thanks, Graham, I'll let you know.

John Watson · Post by **John Watson** » Fri Nov 10, 2017 4:44 pm

Hi Graham, checked the kick start mechanism this afternoon and everything is working as it should, thanks for the heads up, always appreciated.

I took a ride out on Tuesday to see my local guy about a rebore and he told me that there was nobody left in Carlisle who does rebores any more. The nearest outfit was at Dumfries, at a workshop that were customers of mine back in the early nineties. A lovely old chap owned it and every time I visited, he would sit me down in the middle of the shop, give me a large mug of tea and we would chew the fat over anything and everything before we got down to business.

He was of an age that I didn't realistically think he would be around, and when I arrived there yesterday I was met by a charming lady, who, it transpired, was Tom's daughter. she has run the place since her dad passed away 17 years ago. We had a good chin wag about her father, I explained what I was doing with the bike, left the barrels with her and today got a call from her to the effect they'd honed and measured the bores and that a rebore was necessary. I shall be dropping the pistons off with her next week when I get them from David Silvers.

While I was cleaning up and checking over a few bits, I happened to notice that the pistons I removed from the bike had slightly different crowns. Looking more closely one was marked CA77 and the other CB77! I wonder what that did to the running?