I realise, after no less than 50 years taking bikes and complete engines apart and (after the first couple of years....) successfully putting them back together again, I've only ever bought oil seals as either a manufacturer's part or by the markings.
Now, as part of my fascination with stone age machinery, I have an old Chinese sidevalve 750 flat twin sidecar outfit, a Chang Jiang CJ750. It runs actually very nicely despite being even more primitive than my Harley. It needs immediately some fork seals, and I found a couple in its huge tool kit. Sadly they are old and hard with rusted springs, and have a numerical code which seems to relate only to a part number.
What I know is that the fork tubes are 40mm, and the overall size of both seals is 47.5mm. Internally they are 38mm- 2mm under the size of the tubes. So my questions are , is this normal, or do I buy new seals based on the shaft size? I can order the real thing from China, but it will take time and seals from say Timken are likely to be better quality. And no doubt there will be seals in the dripping final drive, the weeping gearbox etc etc.......
I'm very fond of it already. I usually greet it in the voice of a Bond villain, 'Ah so, Mr Chang will see you to your doom Mr Bond.....'.
Now, as part of my fascination with stone age machinery, I have an old Chinese sidevalve 750 flat twin sidecar outfit, a Chang Jiang CJ750. It runs actually very nicely despite being even more primitive than my Harley. It needs immediately some fork seals, and I found a couple in its huge tool kit. Sadly they are old and hard with rusted springs, and have a numerical code which seems to relate only to a part number.
What I know is that the fork tubes are 40mm, and the overall size of both seals is 47.5mm. Internally they are 38mm- 2mm under the size of the tubes. So my questions are , is this normal, or do I buy new seals based on the shaft size? I can order the real thing from China, but it will take time and seals from say Timken are likely to be better quality. And no doubt there will be seals in the dripping final drive, the weeping gearbox etc etc.......
I'm very fond of it already. I usually greet it in the voice of a Bond villain, 'Ah so, Mr Chang will see you to your doom Mr Bond.....'.