E: Engine Timing Gear Set Up

Steve Morris

Well Known and Active Forum User
VOC Member
Hi all. I have removed the timing chest on my Comet series C and am fitting a new ATD. On inspection i noticed that the half time pinion nut was loose with no lock washer...

So, decided that i really needed to remove all the pinions and check as i also had an issue with the bike using oil/smoking. On inspection there were a couple of thrust washers missing/in the wrong place, so i have now removed all the pinions with the exception of the dynamo one, and the pins, and thoroughly check/cleaned all the above. I have done a dry fit (have ordered a new thrust washer kit) and with the correct shims/thrust washers in the correct places (as per P.Richardsons book) i have what i consider to be quite a lot of play in the pinions, id say on average 30-50thou on each one?

I have made a video showing the play. Can anyone tell me if this is correct as i cannot seem to find in Pauls book OR KTB any reference to the correct movement/gaps?

Many thanks,

Steve.

https://youtu.be/ltleq8i8HXs
 

Steve Morris

Well Known and Active Forum User
VOC Member
Thanks Martyn, your a star mate. I did think there was a bit too much end float, ill have a proper read and play over the weekend.

Best regards,

Steve,
 

erik

Well Known and Active Forum User
VOC Member
I can recommend to close the oilway towards the cylinder. You have more oil on the camshaft and this is more important.The Piston has enough oil from the bigend.Erik
 

Steve Morris

Well Known and Active Forum User
VOC Member
Thanks Eric, Where is this oilway? Like i said i have an oil consumption/smoking issue so maybe have more oil going to the bore than is necessary? There is or seemed to be plenty of oil in the chest and cam area..
 

vibrac

Well Known and Active Forum User
VOC Member
As has been recently discussed on here religious adherence to the recomended arrangement of washers on the timing gear is not all ways the best way, in fact know thy Beast actually has a rare error in my edition
 

Bill Thomas

Well Known and Active Forum User
VOC Member
They may be a little loose , But better than too tight,
The Breather needs more play than the others.

The half time nut , I still do like the factory and pin punch,
But to do it up tight, You need to hold the outside of the engine shocker with a chain wrench.
 

Marcus Bowden

VOC Hon. Overseas Representative
VOC Member
A much more positive method I use is drilling and tapping the locking nuts on gear/boxes engine shafts etc.
HALF TIME LOCK NUT IS FROM A SERIES "A" WHEEL HOLLOW AXEL NUT AS THE HEXAGON IS THE NEXT SIZE WHIT-WORTH UP AND GIVES ONE MORE SPACE TO DRILL AND TAP ENABLING TO LINE UP WITH THE TAPPED EXTRACTION HOLES OF THE HARDENED PINION AND AN ALLAN SCREW LOCTITED IN

P1040104.jpg
 

craig

Well Known and Active Forum User
VOC Member
HALF TIME LOCK NUT IS FROM A SERIES "A" WHEEL HOLLOW AXEL NUT AS THE HEXAGON IS THE NEXT SIZE WHIT-WORTH UP AND GIVES ONE MORE SPACE TO DRILL AND TAP ENABLING TO LINE UP WITH THE TAPPED EXTRACTION HOLES OF THE HARDENED PINION AND AN ALLAN SCREW LOCTITED IN.

Thank you , This looks like a great option.
What is the part number to be ordered for this larger nut please?
Craig
 

greg brillus

Well Known and Active Forum User
VOC Member
If it's a series "A" axle nut you wont be able to buy one, only make one.......If the gear itself is a good fit on the shaft with a new key a nice tight fit, the nut should not come loose.........As I've pointed out in other posts, if the fitting itself comes loose due to play in the spline or keyway, then the nut will always loosen itself. I've had several engines where the pinion starts rotating on the shaft with a loose key, at low engine speed it sounds like the big end is gone.
 
Top