Known problems:-
Oil leak around front bottom left engine mounting bolt, caused by using oversized bolt, usually after fitting engine bars or omitting washer. This is a main oil gallery & may result in scrapped crankcases – VERY expensive! I personally would try one of the low temperature alloy welding sticks to attempt a repair, I repaired a cracked generator cover to great effect. If you can solder and can get the case to 380°C it really is an excellent product.
Clutch bearing Honda p/no. 91002-286-008 can wear to the point of it disintegrating, falling into and damaging the gearbox. If there is any play here at all – replace it. Also wear between the clutch basket and primary drive gear, which is riveted to the back. The built in shock absorber springs sag after high mileages, leaving the basket to wobble back and forth on the primary gear. A little movement isn’t too much of a problem, but excessive play means a new clutch basket.
Clutch drag can be caused by worn Washer, Thrust, 25mm 90455-333-010 superceded by 90466-MC7-000 both discontinued and or check cam clutch lifter components.
The needle roller cage 91007-323-000 that sits inside the starter drive gear boss and supports it on it’s shaft can fail at high mileages and cause extensive damage. Replace this if in any doubt with later type P/no. 91007-426-004 especially if you have the engine stripped.
The primary drive rubbers 23114-323-000 of which there are 8 will have to be replaced if there is any degree of free play about the rotational axis. Mine had turned to a hard plastic rather than the rubber they are meant to be.
Quite a few o-rings will also have perished and require replacement. Try the local plumbers merchant first for a cheaper solution to buying genuine spares.
When sealing the crankcase halves, make sure the gasket compound seals the inside edge, i.e. towards the oil sump, of the two non- bolt holes at the front and rear of the engine. Note: parts of the top and bottom halves do not contact each other, mark these areas before sealing compound is applied.
The gearshift selector oil seal mounting hole may be corroded, if so, apply sealing compound before installing the seal, I didn’t and mine leaked. After a thorough degrease the seal was replaced with the sealant and I now have an oil tight engine. This was easily done without stripping crankcases or removing the engine.
Noise from the bottom end is usually a worn primary drive chain – replace if in doubt, this is a major strip down of the entire engine.
Plasti-gauge can be bought on-line if hard to find locally.
Kick starter knuckle joint cracks and splines get damaged due to loosened retaining bolt, use Loctite. An expert welder may be able to repair this as they are now obsolete.
Removing rotor – this is relatively easy providing you have the correct tools. I used a hydraulic 3 leg puller. Unscrew the retaining bolt a couple of turns then fit the puller as tight as possible. Do not think it should now be loose, I had to tap the rotor with a metal hammer to finally release it from the tapered shaft.
Tips:
Wise to use Loctite 243 on all internal engine bolts i.e. big end shell retaining bolts etc. Worth noting Honda didn’t do this, I could see no residue on mine when extracted.
Crankcase and gearbox bolts are specials i.e. marked M8 UBS in parts listing. Also the M6 bolts have a smaller shank than the thread size, worth re-plating these to avoid complications. As with all Honda motorcycle bolts the head size is usually 1mm less than its European equivalent, therefore some bolts will not allow a larger socket to fit.
Always use a paper gasket on the clutch housing to avoid all sorts of problems. The clearances from cover to moving parts is very tight.