Chain Alignment

[Briz]

Gavin; A10s do run 530 chains. (530 is just modern speak for 5/8 x 3/8")
Definitely not 630!! thats 3/4" pitch.
If you have 1/4" sprockets, they are most likely off a single.

Its rare to find a plunger frame thats not bent. Many did sidecar duty which distorts them all over the place. Not helped by a frame design with virtually no crossmembers.

[muskrat]

G'day Gavin.
So it sounds like a PO has put 520 sprockets on and you have put on a 530 chain. 530 is standard for A7/10's.
No need to stress, just throw a 520 chain on. At least now you know everything is straight and in line.

[duTch]

 Easy to throw on a 520 chain if both sprokets are same width, but could well be you have a proper drive sprocket and a narrow chainwheel one...?

By sliding a neat fitting "Zip tie" from the underneath of the bike up between both top and bottom chain links near the drive sprocket I could use a laser to confirm that the alignment between the sprockets is correct. By some sort of miracle it looks like the frame is correctly aligned. I'll gratefully take that one.

 Could be false hope Gav- not to say it is, but could look straight point to point, but the light may only bend horizontally, but not vertically..'round the front of the front sprocket......?

  Is the chainguard off? It was soon after initially recovering mine, and it was at a good height in the back of my van that I noticed mine was out of whack, and after some investigating deduced it was due to having a chainwheel from a A65- they apparently almost the same ,but not enough- replaced that and thought it fixed- but not to be....
 
   .....as I discovered as previously posted (I think).
You asked how I set it up, so'll tell you- not as hard as it may sound and maybe took less time than it takes to write about it...!
The headache started as I'd used different width rims (WM1/WM2), and only closely guessed the offset(not a problem).
When I did the alignment, it was 'bare bones'- frame/wheels-no tyres/forks and empty engine cases but mostly just the complete dry G/box, no clutch, no guards oil tank, or anything unnecessary.
  Made sure the front wheel was centre of forks, and (new) forks straight(not twisted).
 
Used a couple of bits of pine architrave timber bolted horizontal through the valve holes across the wheels to be 'profiles', and string lines outboard, but close as possible to the bike (equidistant is much easier). All that to resemble a box with parallel sides and in the same horizontal plane.
 
Used a couple of short spare pushrods in the mainshaft (clutch adjuster removed) to measure back to axle to ensure parallel....and then I started measuring.
 I'm fairly confident the interface of the top g'box mount and frame lug are close enough to centre of frame.
 There's apparently frame drawings in 'service literature' that may help.
 
 Hope that's a bit of help, I have to go do stuff now-good luck, and hoping it's just the wrong sprocket, but check the front one before a new chain, a chainwheel may be cheaper than wrong chain that you can't use + correct sprocket.
 Sorry that got a bit long winded...
 
 

[wilko]

New replacement sprockets can be dodgy. I had to take about 40 thou of the side of the sprocket on a 520 version for an M20 rigid on the lathe for the chain to fit. The bloke who machined it at the factory probably went outside for a smoke in the middle of his machining!

[duTch]

 maybe meant to do a 525, but it over-machined 'cos he rolled from the wrong packet....

[Gavin]

Thanks all. Will let you know how a slimmer trimmer chain goes?

You guys really give the forum its great value. 

[muskrat]

G'day Gavin. Are you sure the front sprocket is the same as the back? As duTch said you may still have a 530 on the front and a 520 chain won't fit over it. It will be hard to measure with the primary on but must be done.
Cheers

[duTch]

 Just had a thought - you should be able to see it if you look up from underneath.
  Use a mirror, like the rear view one...should still work in up/down mode..

 You should also be able to get up in there with some kind of caliper whatzits (like the old dividers for scribing circles?)
 Surely no point suggesting to split the chain first...?

[Gavin]

Another value of the forum... we get a change to rethink... so having found 2 different sized sprockets on spare gearboxes lying round the shed and measuring them etc, then going back over a few details yep Musky, you got it... the original drive sprocket is 3/8". So that one and the chain are a fit, and I now need a wider toothed rear sprocket.

Yep duTch, I used a home spun format... cut some thick cardboard that I lay along the chain. Each end was cut to the different sprocket width... and yep the wide one fits the drive and the narrow fits the rear wheel sprocket. Seemed like the best techy toy to do the job. Yep mirror does very obviously prove that the sprockets are different.

Thanks again.
Gavin.