Timing Cover Off - What Now?

[BagONails]

Hi Gang, I am bereft of charge and after following the checking procedure from Priory Magnetos to no avail I decided to remove the dynamo and delve deeper into the works.

While I have some limited access to the timing chest I am wondering what the recommended general checks would be from the men who know, in a stitch in time kind of way?

I'm thinking along these lines:
1) Gently try to ease up the crankshaft end looking for any movement and check end float / main bearing wear
2) Run the engine briefly just to view the amount of oil emerging from the bush itself and whether excess oil may be appearing from around the pump / view ATD bobweight function (they seem to be fully closed at rest, fully retarded?)
3) End float on mag drive gear and dynamo drive (can't feel any)
4) Check torque on oil pump mounting nuts
5) Mag drive gear backlash ( this feels considerable to me but may well be normal, I have noticed a fair amount of knocky noise coming from this area on tick over, not deep seated heavy knock like a main or big end but when I rattle the gear back and forth now by hand it seems to cause a similar noise so I wonder if there might be excessive wear on one or both timing gears in the mag drive train and what the limits are?) Hot or cold makes little difference but noise seems to go away off tickover.
6) Check on function of ATD throw-out unit, not sure how but the bob weights seem to be free to move and return, full advance at around 2000 revs?

So what have I missed?

As always any comments, pearls of wisdom, sage advice from you guys always welcome.
Cheers Bagga 

[bikerbob]

I think you have covered just about everything, but I  do not know how old the dynamo chain is but check it for wear and maybe broken rollers also while you are in there you might want to consider changing to a toothed belt drive for the dynamo speaking from experience it is a big improvement on the chain drive. On my own bike with chain drive you had to be doing at least 30mph to show a charge with the headlights on, with a belt drive I can still show a charge at under 20mph. I also use a DVR2 voltage regulator another good mod.

[KiwiGF]

Maybe check the breather end float unless that is what you meant by (3).

[Swarfcut]

 Idler gear shaft should have next to no radial movement and  shaft should have no end float, this is controlled by a cork washer compressed between the inner timing cover and the underside of the dynamo drive sprocket. Often discarded as viewed as an ineffective oil seal. Knocks and clicks at low speeds are normal, the cam and followers all have an element of spring loading which makes them move in a series of jerks at low speed, all documented in the appropriate Forum sections. The same applies to the ATD, but here it is the magnetism of the magneto body playing the trick.

 Dynamo drive sprocket can wear eccentrically so the chain tension tightens and slacks off as the drive turns. Chain runs in grease, it is not lubricated by the engine oil.

 Running without the timing cover is messy, it pours out at a fair rate and most of the oil will end up on the floor and the tank will be empty. With the cover on, the oilpump runs immersed in oil in its own cavity, oil exits from here via the keyhole slot  in the crankcase back to the sump.

  Dynamo is pretty simple. Basic test procedure will show if the fault is the dynamo itself or the charge control system. BSA Service Sheets 804-809 tell all.


 Swarfy.

[muskrat]

G'day Bagga.
Swarfy and Kiwi just about covered it. Get hold of a dial indicator to test the crank end float and bush wear.
While your in there you could drop the pump and OPRV off to clean & inspect. I poke a nozzle from a carb clean can in the crank feed hole and give the anti-syphon ball a squirt (push the ball against it's spring).
+1 for bikerbob belt dyno drive.
Cheers

[RDfella]

Jeez.... why not have a full engine strip whilst you're at it 'just to make sure'. The frame too, just in case ....    And better check that 'sludge trap' whilst you're at it, before GB jumps on you!
Unless something obvious jumps out at you, leave alone. These engines have enough problems without trying to find more.

[Greybeard]

Jeez.... why not have a full engine strip whilst you're at it 'just to make sure'. The frame too, just in case ....    And better check that 'sludge trap' whilst you're at it, before GB jumps on you!
Unless something obvious jumps out at you, leave alone. These engines have enough problems without trying to find more.

Jeez RD keep yer knickers on 

[BagONails]

Well we certainly got an interesting mix of reactions to my questions and a lot of valuable advice. Thank you all for taking the time.  I had come across a few of these points in my recent searches but not all so I'm glad I asked.

I must give RD a special mention for making me laugh , well done mate its fine really, I get it and I know it may seem to some of the older most experienced owners on here that a few of us younger noobs to these venerable, somewhat quirky machines might be being anal or over fussy in our dealings with what are after all just basic workhorse beasts but I always take the view that there is no such thing as a silly question and on that basis I shall continue to keep asking questions because that's how we learn (and hopefully avoid making expensive mistakes or overlooking minor issues that could grow into major ones). I've given RD a like because he has drawn attention to the fact that maybe sometimes we all get a bit carried away with ourselves; the thing is its a hobby after all and I reserve the right to do so!


Cheers and thanks again for your help.
 

[berger]

BON thank goodness someone else has a sense of humour