Part II - Huntmaster charging issue

[Nickfrank]

Thanks for all the comments. The battery is definitely good but I've discovered the yellow and brown wire going into the dynamo where it goes through the rubber grommet has been pinched through the insulation and the wire strands are exposed. This is probably a good place to start but I need to remove the dynamo. I loosened the metal clamp nut fully and rotated the dynamo until it was quite loose in the "cradle" but I can't seem to pull it out. Any advice to remove it would be greatly appreciated. The manual I have gives no specific instructions for taking it out. While it's out I'm going to have a local expert on alternators, generators and the like, look it over and ensure the components are good and it is putting out the required voltage. Thanks again. Nick

[Simon.Gardiner]

Nick
Pretty certain you also need to take the timing cover off so you can unhook the dyno drive chain - if you're unlucky you'll have to take a sprocket off 'cos there won't be enough slack but hopefully you'll be able to fiddle it off.
Having said that I can't remember if the dyno sprocket fits through the hole in the inner cover - but I'm sure someone will be along soon who will know.
(You'll need a drip tray as some oil will come out when you remove the cover.)

HTH

SG

[Steven.Carter]

Yes it fits through the hole ok, it's very small

[Nickfrank]

Silly question probably but is the timing cover the large plate behind the gear selector with the 12 Allen bolts securing it?

[Simon.Gardiner]

It's the one with 'six Twin fifty' inscribed on it that covers the end of the dyno.....I haven't counted the number of screw holes though!!

SG

[Nickfrank]

OK, I have the cover off and the dyno out. Final question, honest! When I put it back in and wind it up, how much tension should go on the chain before I tighten the clamp?

[nevhunter]

See if the tension varies as you rotate it and set to the tightest point. Very little but some, is the answer. It would tighten as the engine gets hot but not much as it's a short chain. Check if the chain is worn when you have it off . The TOO SMALL sprocket is a bit hard on chains. Nev

[Simon.Gardiner]

Had to think about the chain tension question, it's one thing I don't seem to have made a note of......because it's in the Owners Manual (copies available in the AOMCC members online library) - simples!
From the manual:
...adjust the dynamo chain by rotating the dynamo in its cradle to give approximately 1/8"-3/16" up and down play on the chain, but not sufficient to allow the chain to foul the screw boss in the centre of the cover near which the chain runs...

HTH

SG

[pete.collings]

Another thing to consider is whether the two dynamo drive sprockets are in line. This will depend on the thicness of the cork sealing washer(s) that abut the inner timing chest. Aim to minimize the runout between the sprockets, this may not be a critical adjustment, but anything that gives the chain an easier life is beneficial to charging reliability (ie. no broken chain!).
Some of the repro small dynamo sprockets have tapers that leave the sprocket further out than the original, allied with slightly differing tapers on replacement armatures. The small sprocket can be very difficult to remove from the taper if a new bearing is needed, and can easily be damaged in the removal process.

[Nickfrank]

Great feedback! Much obliged.
Nick