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Comet - Primary Chain

Martyn Goodwin

Well Known and Active Forum Website User
VOC Member
1,500 miles back I did a complete engine rebuild of my Comet- that included new everything except for cases, conrod and flywheels. Up to then I had covered almost 5,000 miles and the primary case oil was always clean.
Now, 1,500 miles after the rebuild I have discovered that the primary chain case oil (it is actually ATF) is dirty with speckles of steel (its attracted to a magnet) in it. There is a seal on the mainshaft into the primary chain case and the oil in the sump and UFM is pristine and clear.
Now - I suspect that with the rebuild the lateral position of the mainshaft on the drive side may be different than before resulting in some misalignment of the ESA and the clutch basket sprocket and thus the metal chards.
I have some ideas on how to check - and fix - the misalignment of the primary drive chain though I have never actually done it so I wonder has anyone come across this before and what is the correct and/or proper way to check and fix misalignment in this area?
 
Martyn
 

redbloke1956

Well Known and Active Forum Website User
Non-VOC Member
1,500 miles back I did a complete engine rebuild of my Comet- that included new everything except for cases, conrod and flywheels. Up to then I had covered almost 5,000 miles and the primary case oil was always clean.
Now, 1,500 miles after the rebuild I have discovered that the primary chain case oil (it is actually ATF) is dirty with speckles of steel (its attracted to a magnet) in it. There is a seal on the mainshaft into the primary chain case and the oil in the sump and UFM is pristine and clear.
Now - I suspect that with the rebuild the lateral position of the mainshaft on the drive side may be different than before resulting in some misalignment of the ESA and the clutch basket sprocket and thus the metal chards.
I have some ideas on how to check - and fix - the misalignment of the primary drive chain though I have never actually done it so I wonder has anyone come across this before and what is the correct and/or proper way to check and fix misalignment in this area?
 
Martyn


Hi Martyn, you are having as much "joy" with your Comet as I am, You will probably get some responses about laying rulers across sprockets etc to get alignment, and these would probably do the job.
In my opinion, for what it's worth, the best way would be to use the Inner Primary case as a datum, lay a flat bar of something (I have a length of nicely machined 1" x 3/4" brass bar) across the faces and use a depth micrometer to measure distances from the faces.
The beauty of this is that you can (if you take enough measurements) pick up all sorts of problems eg alignment of the two shafts (parallel to each other) alignment of clutch and engine sprockets (or height of each, if you like) etc..
Good luck with it mate, let us know the outcome.

regards
Kevin (sittin at work gettin overtime:rolleyes:)
 

Martyn Goodwin

Well Known and Active Forum Website User
VOC Member
Today I stripped it all down and with a straight edge (a 12 inch steel ruler) pressed against the main shaft drive sprocket I was able to detect a miss-alignment of around 2mm at the clutch basket sprocket.
 
I located a suitable washer 2.2mm thick that I plan to install behind the clutch basket assembly, thus moving it out and into alignment with the main shaft sprocket. This is in addition to the spacer that Conways provided with the clutch.
 
I am concerned that with the clutch basket just that tad further away from the opening in the case for the gearbox that there may be more of a chance of an oil leak there. To try to prevent that I plan on installing a thin aluminium disk, (made from a beer can) around the same diameter as the clutch basket, sandwiched between the flange of the gearbox shaft and my spacer washer in the hope it will act as a rudimentary oil slinger.
 
Constructive comments please.
 

redbloke1956

Well Known and Active Forum Website User
Non-VOC Member
Today I stripped it all down and with a straight edge (a 12 inch steel ruler) pressed against the main shaft drive sprocket I was able to detect a miss-alignment of around 2mm at the clutch basket sprocket.
 
I located a suitable washer 2.2mm thick that I plan to install behind the clutch basket assembly, thus moving it out and into alignment with the main shaft sprocket. This is in addition to the spacer that Conways provided with the clutch.
 
I am concerned that with the clutch basket just that tad further away from the opening in the case for the gearbox that there may be more of a chance of an oil leak there. To try to prevent that I plan on installing a thin aluminium disk, (made from a beer can) around the same diameter as the clutch basket, sandwiched between the flange of the gearbox shaft and my spacer washer in the hope it will act as a rudimentary oil slinger.
 
Constructive comments please.

Martyn, check with Ken Phelps ?, I am sure he posted something recently about this very issue....could be wrong .....because I have been ONCE before (1974 ish?) I think it was something about a sliding slinger to allow for gearbox movement when adjusting Primary chain

Kev
 

Martyn Goodwin

Well Known and Active Forum Website User
VOC Member
Martyn, check with Ken Phelps ?, I am sure he posted something recently about this very issue....could be wrong .....because I have been ONCE before (1974 ish?) I think it was something about a sliding slinger to allow for gearbox movement when adjusting Primary chain

Kev
In acknowledging that one was once wrong; does that make one right or simply confirm the wrongness? I do know that Ken did write (as opposed to right, not wrong) in 998 a few months back about the use of a beer can - regrettably empty - to create a sling seal and I am going to follow in his footsteps - of course I will use a Fosters can. Regardless I have had a communication from Conway's who suggest that the expedient of the spacer washer is a good thing - and also bemoaning the lack of a sliding seal (aka BSA) in the primary chain case. Did I mention that as a consequence of this nonsense I also pulled the gearbox and replaced the kick start quadrant AND matching pinion in order to resolve the kick starter jamming? Lovely new parts from the VOC. Polished with care and fitted with love by yours truly. Slimy, messy job with a grease filled box - devilish stuff. Bugger me! First actuation with all the new bits - Yep, correct. Bloody thing jammed! Oh well - lets just call that - CHARACTER! Completely Horrible And Ratshit Contraption Tending (to) Eliminate Respect. Martyn (after way too much refreshment!)
 

redbloke1956

Well Known and Active Forum Website User
Non-VOC Member
In acknowledging that one was once wrong; does that make one right or simply confirm the wrongness? I do know that Ken did write (as opposed to right, not wrong) in 998 a few months back about the use of a beer can - regrettably empty - to create a sling seal and I am going to follow in his footsteps - of course I will use a Fosters can. Regardless I have had a communication from Conway's who suggest that the expedient of the spacer washer is a good thing - and also bemoaning the lack of a sliding seal (aka BSA) in the primary chain case. Did I mention that as a consequence of this nonsense I also pulled the gearbox and replaced the kick start quadrant AND matching pinion in order to resolve the kick starter jamming? Lovely new parts from the VOC. Polished with care and fitted with love by yours truly. Slimy, messy job with a grease filled box - devilish stuff. Bugger me! First actuation with all the new bits - Yep, correct. Bloody thing jammed! Oh well - lets just call that - CHARACTER! Completely Horrible And Ratshit Contraption Tending (to) Eliminate Respect. Martyn (after way too much refreshment!)

Martyn, If a man speaks in the forest and there is no woman to hear ...is he still wrong....That's all I got (after just enough neck oil)...I assume you have read about the repair for a jamming kickstart in Burmans?
 

Martyn Goodwin

Well Known and Active Forum Website User
VOC Member
Martyn, If a man speaks in the forest and there is no woman to hear ...is he still wrong....That's all I got (after just enough neck oil)...I assume you have read about the repair for a jamming kickstart in Burmans?
Just where/what can those repair instructions be found?? I was silly enough to assume that fitting new old parts plus polishing the lead-in 1/2 tooth would have solved the problem. Martyn
 

ogrilp400

Well Known and Active Forum Website User
VOC Member
G'day Blokes,
Chains will tolerate a reasonable amount of misalignment but 2mm over that short a distance is probably pushing it. Martyn, have a look at the sides of the sprockets and the insides of the chain and that will give you some idea as to how bad things are. The slinger I wrote about is only about .006" thick so that won't effect things too much but spacing the clutch out on the gearbox mainshaft 2mm will almost halve the engagement of the spline on the clutch basket with the gearbox mainshaft. There has been few instances of these splines failing through rocking wear.

Phelps.
 

Martyn Goodwin

Well Known and Active Forum Website User
VOC Member
G'day Blokes,
Chains will tolerate a reasonable amount of misalignment but 2mm over that short a distance is probably pushing it. Martyn, have a look at the sides of the sprockets and the insides of the chain and that will give you some idea as to how bad things are. The slinger I wrote about is only about .006" thick so that won't effect things too much but spacing the clutch out on the gearbox mainshaft 2mm will almost halve the engagement of the spline on the clutch basket with the gearbox mainshaft. There has been few instances of these splines failing through rocking wear.

Phelps.
Thanks Ken, The drive sprocket looks just fine but there is obvious, but not severe, wear on the faces of the clutch sprocket. The Honda Conway basket has full depth engagement on the mainshaft splines so that should not be a problem. Mail from Conways recommends I use the extra spacer. Not prepared to chance the chain, so a new one will b e going in. Martyn
 
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