Well, I had an absolute ball at the Manx Grand Prix - 35 minutes and 28 seconds does not seem fast for a Parade Lap I guess, but it sure felt it for me! I have the entire lap on high definition head cam fixed to my helmet and so will be uploading that in two sections to You Tube when I get the necessary skills sorted.
Having completed 800 miles to and fro the French Rally faultlessly for my speedo I was pretty hacked off to snap speedo cable number 8 just 2 days into the Manx GP whilst out on track at Jurby. I found that the vertical gear in PR32 (the one with the slot in the top that the spade drops into) had dropped down the gearbox and the spade was only just touching/engaging - so I drove it further up and fitted the split pin that had been missing for some long time (like all of my ownership since 2007). Then, in less than 12 miles of light duty (0-40 mph) it snapped again. Then one more time within 4 miles. So, all in all now, 10 cables - all in exactly the same spot, the lower end of the cable where it is squared and drops into the spade connector.
The 5 inch clock has been back to David Woods at least twice and been all checked out.
The right angle gearbox at the head end has been regeared.
The PR32 wheel drive shafts are sloppy and worn, but the gears seem to engage.
The spade connector does not run true when you raise the front wheel off the ground and leave just the spade in the drive and spin the front wheel, it runs very out of true.
Having spoken today to David Woods at Netley he recommended that the spade must be made to run true and trying an original spade might help as the thickness of the spade section is materially thicker than the reproductions being used. I have an original so have popped one in and it is still running quite out of true, and the thicker original spade is a sloppy fit in the slot on top of the vertical gear shaft.
1 - Do you agree with my analysis so far that likely cause is:
1.1 An intermittent seize fault somewhere in the Speedo head or right angle drive (not likely as the tension required to snap the cable would likely do some damage in the speedo)?
1.2 The spade running out of true and causing a friction fracture of the cable at it's weak point where the round is made into square?
2 - If 1.2 is rightThen has anyone got any bright ideas on how I could have the PR32 overhauled and repaired? A new one appears to be listed at £200 PLUS 20% VAT - no thanks!!!!! Can anyone recommend someone to me to do the work?
3 - Has anyone got a spare PR32 I could try?I wonder if anyone has a spare PR32 that I could borrow to try and run on my bike to see if this solves the problem - a little challenging as the 800 miles of faultless run to and fro the Loire Valley suggests it is an intermittent fault. BUT substitution is the best route perhaps to nail down the problem.