My CB72 engine has been sitting patiently on the bench fo rsome months while I galivant around the world. When I get back from one of my trips it takes me a while to get my 'fettling coordination' back so I just do small jobs until I am ready for the serious stuff again.
I rummaged out the parts to assemble my recently-purchased tacho drive. There was a freshly-plated housing fro the drive gear with all the washers, O-ring and retaining screw. Interestingly the first gear housing I found would not go in teh bore but I found another that would.
I had to check the manual to see that there are two thrust washers on the skew gear. They both are rather loose on the shaft but definitely the correct ones.
The cover went on nicely with a few drops of oil on the drive shaft and a fresh gasket. Despite all of the screws I had re-zinced, I could not find a set of nice looking screws of the right length. An order went off to David Silver for a complete set of replacements..
The cover for the points side is again different on early bikes. It has these extra fins which blend the cover with teh head fins. These disappeared on later bikes.
The screw problem affected the points cover screws which are the dreaded 5x30 JIS thread. The points cover itself on these early bikes had no "Type" lettering cast in. I could only find one suitable screw and the thread was already damaged in one of the holes so I bought a bag of 100 5x30 ISO screws and a helicoil kit so that I can make the problem go away for good.
Just to illustrate the difference between the JIS (0.9 pitch) and ISO (0.8 pitch) here they are.....
I thought that I bought some suitable JIS screws a while back but cannot find them. It's hard when you don't have a factory with all the bits lined up.
G
