Help - bike's gone bang!

[chaterlea25]

Hi
Oil is cheap compared to engine rebuilds

John

[Worty]

UPDATE - Removed timing cover and ATD - half the teeth were missing from the fibre drive.  Thanks for pinpointing the problem.  I have the info to replace the drive but not really the time.  However, my engineer mate will help out if I can get a drive.  He says I need to get a Tufnol fibre drive and not plastic (didn't thing there were plastic ones out there and I'm not that daft).  However, can anyone recommend a supplier.  Have seen some on Ebay on sale from£12 to £22 which state they are fibre replacements - what do you reckon?

Because the tiny amount of debris in the timing chest doesn't correspond at all with the volume of missing teeth, it does like I'll have to change the oil and clean sump gauze, tank, etc.  I'm told that any debris should have made it to the gauze or to the filter/bottom of the oil tank.  I guess there's not much else to do if bits are still in the engine (shouldn't be much as the bike packed up pretty damn quick).

Someone did mention an ally drive, but I think these are for the manual A/R only.  Happy to stick with fibre.  Any reasons, apart from age, why the teeth stripped?  Mag turns freely!

Cheers again all!

[Triton Thrasher]

Likely there was too much pressure put on the teeth last time the nut was tightened up.

I stick a screwdriver through the ATD yoke to push back against the spanner turning the the nut, to avoid straining the fibre teeth.

[Greybeard]

...can anyone recommend a supplier.

Priory Magnetos. https://sites.google.com/site/priorymagnetos/magneto-atd-spares

In case you do not know; Priory is run by Andrew Guttmann alias Beezermac, Resident Legend of this forum.

[Worty]

In case you do not know; Priory is run by Andrew Guttmann alias Beezermac, Resident Legend of this forum.

No, I didn't know that.  Priory is excellent!

Actually found a lot more debris at the bottom of the timing chest underneath the *oil pump*?  Still doesn't account for all the missing teeth though.

What about the drive gear - any suggestions as to supplier.  Will ensure I don't put pressure on the fibre teeth.  Incidentally, the self-extracting bolt holding the unit on wasn't tight at all - is there a recommended torque or is it a nip up job.

Finally, a stupid question to many.  When timing it up with the r/h pot at TDC, I turn the crank back 32 degrees - is 'back' anti-clockwise as I look at the timing cover?

Cheers again.

[Greybeard]

Finally, a stupid question to many.  When timing it up with the r/h pot at TDC, I turn the crank back 32 degrees - is 'back' anti-clockwise as I look at the timing cover?

Plugs out, bike in fourth, on the centre stand. You can easily turn the engine forward or backward using the back wheel.

Andrew may be able to help with the timing gears.

[KiwiGF]

In case you do not know; Priory is run by Andrew Guttmann alias Beezermac, Resident Legend of this forum.

No, I didn't know that.  Priory is excellent!

Actually found a lot more debris at the bottom of the timing chest underneath the *oil pump*?  Still doesn't account for all the missing teeth though.

What about the drive gear - any suggestions as to supplier.  Will ensure I don't put pressure on the fibre teeth.  Incidentally, the self-extracting bolt holding the unit on wasn't tight at all - is there a recommended torque or is it a nip up job.

Finally, a stupid question to many.  When timing it up with the r/h pot at TDC, I turn the crank back 32 degrees - is 'back' anti-clockwise as I look at the timing cover?

Cheers again.

Yes anti clockwise. Easy way to remember is yr engine turns in the same direction as your wheels 

Theoretically the fibre teeth junk should end up being stuck on the sump gauze, but smaller particles may have got through that and then gone through yr pump and back to the oil tank and then recirculated around etc etc, also some junk may still be stuck on the inside of cases.

I suggest you clean the sump and tank gauze filters and change yr oil, run it for few miles and then clean the gauze’s and change it again. Repeat as many times as you feel necessary!

Tip.....use cheap oil. 

[duTch]

 In addition, rather than just rolling the crank back to the required degrees, either go further back and come up to the mark or go right around in working crank motion and come up to it..... this helps remove any backlash in the timing gears

[Worty]

Brilliant, great info.  Sorry for all the questions but:

Presumably I have to make sure the slipring copper strip is showing on the top pick up which corresponds to the r/h pot at TDC and that the points are on the cam are open.  Is this right.  Just thinking about getting the pot at TDC but having the mag at the wrong point of rotation.  Someone mentioned fag papers in the points - how do you time the points with the position of the piston?

[KiwiGF]

Brilliant, great info.  Sorry for all the questions but:

Presumably I have to make sure the slipring copper strip is showing on the top pick up which corresponds to the r/h pot at TDC and that the points are on the cam are open.  Is this right.  Just thinking about getting the pot at TDC but having the mag at the wrong point of rotation.  Someone mentioned fag papers in the points - how do you time the points with the position of the piston?

Too much time wasted messing about with points  is why I installed an electronic mag! You could do the slip ring thing or just swap the leads over if it won’t start.

You have to (repeatedly  ) turn the engine forwards and feel when the fag paper is let go. Then se how far before TDC it is.

Practice makes perfect etc, everyone has a preferred method

You are lucky if the mag pinion does not move slightly when you tighten it making the process a bit of trial and error (but then having an electronic mag I’ve had less practice than most  )

[Greybeard]

In addition, rather than just rolling the crank back to the required degrees, either go further back and come up to the mark or go right around in working crank motion and come up to it..... this helps remove any backlash in the timing gears

Yes indeed.

[Worty]

Thanks all

I take it that the timing method is trial and error.  I get the fag paper thing now, but is it (the fag paper) released at 32 degrees BTDC or at TDC.  I'm guessing points start to open at 32 degrees (fag paper pulls out) and are fully open by TDC (points at apex of camring).

[a101960]

If you want to eliminate an doubt about when the points are about to open, forget fag papers and get one of these. Best thing I ever did. The one I have lights up an LED, and buzzes when the points are just breaking. It makes life very much easier when timing a magneto. I have no idea how it works, but take it from me it does.

https://www.ebay.co.uk/i/282869499077?chn=ps&adgroupid=54682298551&rlsatarget=pla-413984951703&abcId=1133906&adtype=pla&merchantid=6995734&poi=&googleloc=9045594&device=c&campaignid=1058607774&crdt=0

[chaterlea25]

Hi Wortluck,
When setting the timing, do not forget to wedge the auto advance unit fully against the spring action
Points just breaking at 32 BTDC,(fag paper comes loose)
I would not be without my mag timing gadget, old age is a bastard

John

[Greybeard]

If you want to eliminate an doubt about when the points are about to open, forget fag papers and get one of these. Best thing I ever did. The one I have lights up an LED, and buzzes when the points are just breaking. It makes life very much easier when timing a magneto. I have no idea how it works, but take it from me it does.

https://www.ebay.co.uk/i/282869499077?chn=ps&adgroupid=54682298551&rlsatarget=pla-413984951703&abcId=1133906&adtype=pla&merchantid=6995734&poi=&googleloc=9045594&device=c&campaignid=1058607774&crdt=0

I have used my multimeter to show the change in resistance when the points open but it's not easy keeping croco clips on the bits as you fiddle so last time I used fag paper and it worked fine.