More motorcycle maintenance today: changing the tyres and the clutch plates. Tyres were a bit of a pain (glad I bought new tubes, one of the old ones ripped right off the valve stem!), clutch was easy barring the huge timewaste of scraping all the crust old gasket off and picking bits out of the oil galleries.
Old clutch plates. It's hard to see in the photo, but they're worn so flat that the metal 'tabs' around the edge are preventing them from wearing any further once the clutchpack is assembled. I suspect none of the previous owners ever replaced them and they are still the original factory plates (the original and awful Nissin brake pads were still there until I changed them)
New plates stacked in clutchpack ready to be slid into the clutch basket. You can see how the 'teeth' are much taller than the worn plates. In between these friction plates with tabs sticking outside are steel plates with tabs pointing inside. When the clutch is assembled, the engine will power the outside of the 'basket' the clutch sits in and spin the friction plates. The steel plates spin the centre of the clutch, which attaches to the transmission and wheel. The clutch 'pack' is pressed together by a set of string springs, so the engine drives the outside which spins the fraction plates which spin the steel plates which turn the wheel. When you pull the clutch lever in, this relaxes the springs, which allows the friction plates to slip against the steel plates. The outside and friction plates still spin with the engine. but the steel plates can stay stationary without the engine stalling.
Here is where the clutch sits. The clutch basket sits on the left, and you can see the concentric drive and driven shafts. On the right is where the centrifugal oil filter sits (has to be removed to remove the clutch). That green gunk around the edge is the remnants of the gasket, most of which is left glued to the face of the cover (not pictured). The clutch itself sits within the engine case and is immersed in engine oil, which is why using engine oil intended for cars in a motorcycle is not generally a good idea: Oil benefits from being 'slippery', so car oils contain substances that reduce the effective friction of the oil beyond its normal lubrication effect. When these oils are used in a car with a 'dry' clutch (some motorcycles also have dry clutches, e.g. some BMWs and Ducatis), this works just great. With a 'wet' clutch where the clutch sits in the oil, this can cause the clutch to start slipping even when engaged as the friction-reducing additives collect on the surface of the friction plates.
Old clutch plates. It's hard to see in the photo, but they're worn so flat that the metal 'tabs' around the edge are preventing them from wearing any further once the clutchpack is assembled. I suspect none of the previous owners ever replaced them and they are still the original factory plates (the original and awful Nissin brake pads were still there until I changed them)
New plates stacked in clutchpack ready to be slid into the clutch basket. You can see how the 'teeth' are much taller than the worn plates. In between these friction plates with tabs sticking outside are steel plates with tabs pointing inside. When the clutch is assembled, the engine will power the outside of the 'basket' the clutch sits in and spin the friction plates. The steel plates spin the centre of the clutch, which attaches to the transmission and wheel. The clutch 'pack' is pressed together by a set of string springs, so the engine drives the outside which spins the fraction plates which spin the steel plates which turn the wheel. When you pull the clutch lever in, this relaxes the springs, which allows the friction plates to slip against the steel plates. The outside and friction plates still spin with the engine. but the steel plates can stay stationary without the engine stalling.
Here is where the clutch sits. The clutch basket sits on the left, and you can see the concentric drive and driven shafts. On the right is where the centrifugal oil filter sits (has to be removed to remove the clutch). That green gunk around the edge is the remnants of the gasket, most of which is left glued to the face of the cover (not pictured). The clutch itself sits within the engine case and is immersed in engine oil, which is why using engine oil intended for cars in a motorcycle is not generally a good idea: Oil benefits from being 'slippery', so car oils contain substances that reduce the effective friction of the oil beyond its normal lubrication effect. When these oils are used in a car with a 'dry' clutch (some motorcycles also have dry clutches, e.g. some BMWs and Ducatis), this works just great. With a 'wet' clutch where the clutch sits in the oil, this can cause the clutch to start slipping even when engaged as the friction-reducing additives collect on the surface of the friction plates.
