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Misc: Everything Else Comet: primary chain oil leaking out mainshaft hole behind clutch

RapHRD

Website User
VOC Member
I'm sure this has been discussed plenty of times before, but how do you seal off the hole in the inner primary cover that the gearbox mainshaft goes through to prevent primary chain oil leaking out?
 

Bill Thomas

Well Known and Active Website User
VOC Member
When ?.
The works Norton's were at the Airfield weekend, When I did my 141.9 average,
But not there on Saturday, When we had a tail wind !!, So I beat them !!. On my road Special,
In the Road class.
There racer did 147 mph. I think it was Dave Rawlins, Top Bloke !.
 
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MartynG

Well Known and Active Website User
VOC Member
I fail to see how a sliding seal that moves in a straight line can work with a Comet because as you move the gearbox (to adjust the primary chain) the gearbox main shaft moves in an ARC!

Martyn
 

brian gains

Well Known and Active Website User
VOC Member
i used / made up a felt seal when sorting all the Comet gearbox issues last winter but once that becomes saturated it will drip.
I don't get bent out of shape about machines dripping a little oil but where it is just cheap design, think pressed steel cover with V band and strap to hold in place, I forego oil in primary case and just give a squirt of chain oiler
 

Bill Thomas

Well Known and Active Website User
VOC Member
The only thing with the Primary level for me is, Because the level and the drain are so close,
I am not sure how to check it ?, I think it should be when the Bike is on the ground,
So if you had a sidecar etc,
Can't see that it should be done on the rear stand ?,
I made a "D" Stand a few years ago, And checked it on that the other day,
But as long as the chain lower part is dipped in oil I think it will be OK ?,
But if overfilled you will have a leak !.
 

vibrac

Well Known and Active Website User
VOC Member
I fail to see how a sliding seal that moves in a straight line can work with a Comet because as you move the gearbox (to adjust the primary chain) the gearbox main shaft moves in an ARC!

Martyn
The bike (Trials Chain cam) has a Albion gearbox not sure how its adjusted (Yet") in the tubular frame
"Maybe in one of the 100 photos we took
 

bmetcalf

Well Known and Active Website User
VOC Member
I fail to see how a sliding seal that moves in a straight line can work with a Comet because as you move the gearbox (to adjust the primary chain) the gearbox main shaft moves in an ARC!

Martyn
Maybe enough slop in the guides to allow the small deviation from straight? I don't have actual measurements, but I calculate that if the G/B swings 50mm and the pivot and the free end are 150mm on center, the slop needed is approximately 2mm.
 

Marcus Bowden

Well Known and Active Website User
VOC Member
I could go and measure it but a bit chilly out the back, but like Bruce says it's not a lot of vertical movement required, on reassembly I had been thinking of fitting a grommet in the hole after enlarging.
bananaman.
 
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