No major problems on my machine. Slight corrosion damage to clutch components due to engine being stored drained of its engine oil. Remember it is better to leave dirty oil in the engine than no oil at all.
Known problems:-
Transmission Whine – See Clutch.
Phosphor bronze bearing bush inside the main shaft first gear pinion wears.
Primary drive chain wears after 40,000 miles, dependant on how often the oil has been changed. The 8 x cush drive rubber wedges tend to harden, allowing some backlash. Take up the slack with shims or replace.
The rear wheel sprocket cush drive rubbers also wear at around 40,000 miles and are a pig to replace. One fellow enthusiast did the following after first removing the inner cores rubber also with a 5mm metal burr tool:-
1) Using a Dremel with a metal burr tool (approx 8mm diameter) “machine” a groove down the inside of the steel cylinder, to reduce the metal thickness. (as near to all the way through as you dare!!)
2) Using a small screwdriver, hammer either side of the weakened section inwards to force the cylinder away from the hub wall and into the centre of the cylinder
3) Now using the screwdriver, chisel down the reduced section until you can’t avoid marking the hub wall.
4) Repeat 2 and 3 until you can grab one of the metal “Tangs” you have created using stout pliers.
5) Grab the “tang” and twist back and forth and pull up (WD40 helps) and they come out.
For me, each cylinder took 5 mins to remove and no damage to the hub. Peter W.
First impressions when riding the re-built machine are lots of backlash in the transmission, this is quite normal on these old Hondas.
Final drive chain
The original drive chain on this machine was a heavy duty DID/RK with 96 links and 530 size with a pin length (i.e. width) of 21mm. O-ring chains have a pin length of around 24.5mm, this leaves about 0.5mm or less clearance to the crankcase and may rub on an OEM rear wheel sprocket guard. It is safest to stick with the HD chains to avoid crankcase damage but be prepared to replace it every 9,000 miles or so. With a thorough cleaning/lubrication routine you may more than double its working life.
To check for wear, clean off old grease with white spirit or paraffin. A 300mm section of chain should have no more than 6mm of play in the links, fully compressed to fully extended.
There are 520 size Gold O-ring chain and sprocket kits available in Japan, but at around £200 rather pricey.
The chain case has a hole blanked with a rubber grommet. This is a service aid, a pin can be passed through to hold the drive chain when removing the rear wheel.
Clutch
The clutch on my bike was not smooth pulling from a standstill or holding on clutch on an incline, I would decribe it as ‘a low frequency drag’ rather than judder. Inspecting the plates they seemed flat to the eye, but I decided to change the whole assembly as I had a spare. Result was silky smooth clutch and the bonus was, the awful whine at 4,000 RPM was also gone.