Life after the Slow Monster Rebuild

350TSS · 29-04-2021, 12:44 AM

My niggling concerns are:
1. for a dry clutch there was oil in the clutch basket, not a lot but if it is supposed to be dry is should be dry. There are two possible sources a) where the clutch push rod exits the input shaft, there is a seal here that is completely bespoke, domed and shaped to fit the gearbox input shaft and because it is bespoke probably unobtainable; and b) between the LH casing and the primary drive gear on one side and the clutch basket on the other. Since I have not stripped this down yet I have no idea whether or not it is a bespoke part but I suspect the since the shaft is c22mm (compared to the pushrod seal at c6mm) this seal is subject to higher speeds and therefore more likely to be the culprit.
2. the green seal at about 7 o'clock on the main crankcase picture above has a substantial indent where it fits into the oil pump in the outer LH casing, I have no idea whether there is is a standard / available replacement.
3. the reason for all this mayhem, the kick starter return spring, is not broken. I am almost certain the casing has never been off since it left the factory in 1976. The symptoms that lead to this were a kick starter lever that would only reluctantly return to its stop position and if the engine was running the lever would droop downwards and the ratchet would start singing. The spring itself is not a flat clock spring but a circular section spring, As such, the possibility of winding it up one more complete rotation to ensure it is positively motivated to return the kick starter lever to the upright position is not really an option as the spring will be coil bound on the kick starter shaft. Anyway, why would the factory not supply the bike with the spring tension properly set, and would not the first owners have insisted that if it had been incorrectly set that it was rectified? There is definitely some slack in the tension of the spring when it is abutted to the retaining post that would lead to the lever dropping off the vertical "home" position.
Over the next few days, I shall
1. research availability of clutch oil tightness seals (pushrod and main input shaft)
2. research availability of clutch cover /oil pump seals
3. design and make a component to ensure sufficient tension in the kick starter return spring such that the lever is sufficiently motivated to return 100% of the time to its "home" position
4. make the replacement clutch spring posts and weld them into the clutch hub

29-04-2021, 12:44 AM	#15
350TSS Too much time on my hands member Join Date: Jan 2013 Location: Shipbourne Bike: M900 Posts: 1,419	My niggling concerns are: 1. for a dry clutch there was oil in the clutch basket, not a lot but if it is supposed to be dry is should be dry. There are two possible sources a) where the clutch push rod exits the input shaft, there is a seal here that is completely bespoke, domed and shaped to fit the gearbox input shaft and because it is bespoke probably unobtainable; and b) between the LH casing and the primary drive gear on one side and the clutch basket on the other. Since I have not stripped this down yet I have no idea whether or not it is a bespoke part but I suspect the since the shaft is c22mm (compared to the pushrod seal at c6mm) this seal is subject to higher speeds and therefore more likely to be the culprit. 2. the green seal at about 7 o'clock on the main crankcase picture above has a substantial indent where it fits into the oil pump in the outer LH casing, I have no idea whether there is is a standard / available replacement. 3. the reason for all this mayhem, the kick starter return spring, is not broken. I am almost certain the casing has never been off since it left the factory in 1976. The symptoms that lead to this were a kick starter lever that would only reluctantly return to its stop position and if the engine was running the lever would droop downwards and the ratchet would start singing. The spring itself is not a flat clock spring but a circular section spring, As such, the possibility of winding it up one more complete rotation to ensure it is positively motivated to return the kick starter lever to the upright position is not really an option as the spring will be coil bound on the kick starter shaft. Anyway, why would the factory not supply the bike with the spring tension properly set, and would not the first owners have insisted that if it had been incorrectly set that it was rectified? There is definitely some slack in the tension of the spring when it is abutted to the retaining post that would lead to the lever dropping off the vertical "home" position. Over the next few days, I shall 1. research availability of clutch oil tightness seals (pushrod and main input shaft) 2. research availability of clutch cover /oil pump seals 3. design and make a component to ensure sufficient tension in the kick starter return spring such that the lever is sufficiently motivated to return 100% of the time to its "home" position 4. make the replacement clutch spring posts and weld them into the clutch hub