Practical Sportsbikes (UK)
Shaft seal shot
The gearbox shift shaft seal on my TDR has developed a worsening leak. I had the engine rebuilt last year and haven’t used the bike much. Is it possible to replace this seal without stripping the engine again. My heart sinks at the prospect of having to pay to get it done, and I don’t feel I have the skills to attempt it myself.
Joe Lilley, email
Alan Seeley says: Yes, is the short answer. Careful wielding of a couple of small engineer’s picks should be enough to pull it out. Attack the seal itself rather than trying to prise between it and the cases. If it proves particularly reticent, a couple of small self-tapping screws inserted into the seal will give you something to get a grip on with needlenose pliers.
On fitting the new seal, put a single layer of insulation tape over the shift shaft splines and lube the seal’s inner lip to help it slide over to avoid nicking the rubber – that could be what happened when the current one was fitted.
However: the rubber seal’s thin lip can wear a groove in the shaft, and a new one won’t address the issue. The shaft can also be replaced without a full stripdown – you just need to remove the clutch, which isn’t a complex task.