The GL series engines are some of the smoothest engines ever made for motorcycles.

This is in part due to the over engineering of various parts of the engine with liberal use of shock absorbers throughout the engine and drive line

One shock absorber that is rarely even noticed is the vane / rubber block version inside the alternator drive shaft body.

Being situated inside the engine and subjected to heat from all the hot oil being directly dumped onto the drive gears from the primary chain oil catch trough, the rubber blocks become rather more like blocks of stone, and so do nothing to reduce any shocks or vibration.

If you are finding little black bits when you change your oil, this is most likely where they are coming from.

I am convinced that sometimes the rattle normally attributed to a worn primary chain could well be because these rubbers are disintegrating and not able to control the to-&-fro motion of the heavy alternator rotor. So there could be a rattle from the vanes of the shock absorber, the alternator drive gear teeth and the primary chain as the motion is transferred to it.

The remedy is relatively simple, but the engine has to be removed to do it. Remove the rear casing and the alternator rotor, taking care not to loose any of the starter clutch parts, unbolt the drive unit and pull it out of the crankcase.

The (very) strong spring has to be compressed to remove the split collets and spring cap before being removed. I did it by clamping the one side of assembly in the big vice and using a large G clamp on the other side. Not perhaps the best way, but this was a one off job and difficult to justify making a tool up for it.

Make sure that the spring is facing away from you, just in case!

Remove the pressure plate and take off the external circlip behind it.

Pull the gear drive assembly off the shaft.

Split the gears to make handling easier.

Next, lever the front vane plate out from the blocks in the smaller gear and remove the old blocks. They will be easily removed in most cases. You will be amazed at the state of them! Rock hard, with pieces splintered off them, most likely.

Remove the old blocks from the large gear

You will need 12 Honda part number 13436-371-000. They cost around $5 each.

Lube the new blocks with Vaseline or similar and, using the vice, insert them into the gears.

Now lube up the vanes in the outer vane plate and press it into the small gear with the vice.

Lube the vanes on the drive shaft plate and press the large gear onto the vanes. This is not so easy; you may need to clamp it on one side in the vice and use a G clamp on the opposite side.

Slip the centre stopper plate onto the shaft, followed by the small gear assembly and fit the circlip.

Re-assemble the spring, spring retainer and collets taking the same care as before.

Job done!