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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?
 

greg brillus

Well Known and Active Website User
VOC Member
On Dave's Clutch I had to shim the springs on account of the clutch slipping due to the increase in torque from the bigger engine (my racer is worse as the engine is bigger again) so a slippery oil will only make that issue a bigger one. Sometimes you have to go with what works.........You modify one thing and something else down the chain gives trouble.......Nothing new there.
 

Bill Thomas

Well Known and Active Website User
VOC Member
When I was racing my Comet , I used a Load of Commando sintered bronze plates,
I hand cut them to Burman splines, They did gum up after a bit and I had to wash them off,
But my poor old hands can't use a heavy clutch now, So for the road, Am back to standard plates.
One time Dave Jones and me entered road and race class each !! On my Comet,
for a 1/4 mile sprint at Santa Pod, She had a hard day that day !.
 

vibrac

Well Known and Active Website User
VOC Member
You would go a long way to beat a Newby Clutch its only available with belt drive (I once checked with Bob himself) but if you were a chain fanatic it would not be beyond a Vincent person to piggy back it on a Comet chainwheel
 

Hugo Myatt

Well Known and Active Website User
VOC Member
I was having issues with clutch 'sticton' or drag with my clutch. After consulting the experts in clutch friction materials at EBC in the UK I was told by them that ATF should NOT be used in a motorcycle clutch as will cause the formation of gums on and IN the friction material and the only fix is to replace with new, not ATF contaminated bits.

Their recommendation is to use a motorcycle specific transmission oil, they mentioned Motul TransOil 10W30 and I have used it ever since.

FWIT I have attached the latest instructions for setting up a 'conways' honda clutch in a Comet.

Martyn
In my experience with the Comet clutch using ATF in the chaincase works initially but after a while it leads to sticking plates. Now like Martyn I use Motul TransOil, which seems to be satisfactory.
Leaving the Comet parked on the left side propstand for any length of time is likely to cause engine oil to seep into the chaincase.

Hugo
 

greg brillus

Well Known and Active Website User
VOC Member
Unless the bearing design is different for the road version, which i seriously doubt there is........I would not be inclined to use a Newby clutch on a road bike......... I don't feel the hub bearing is able to last long in service.
 

oexing

Well Known and Active Website User
VOC Member
Sealing a gearbox input shaft when you got a primary chain to tension you obviously cannot have a typical shaft seal as it will never be concentric to the shaft. So you could do an easy mod and have a v-ring, no metal in it, on the gearbox shaft or chain sprocket , axially sealing on a stainless plate or on the alu inner cover, no problem. The lip is very soft and mounted in the oil side , effect is like a slinger seal. So then you can have some range for tensioning the chain as long as the lip stays on the ss plate. My photos show same place on a prewar Horex primary - and a Kawa clutch on it, with a v-ring sealing on a ss plate.

Vic
V-ring
P1030165.JPG

P1030170.JPG
 

vibrac

Well Known and Active Website User
VOC Member
I am sure on some long gone British single( Ariel VH?) or even a BSA (god forbid!) there was a sliding shutter arrangement made of a tin plate with an oval hole riveted to the back of the chaincase with a bent up groove formed along the top and bottom and a sliding shutter with a shaft hole in it, very neat. I guess the bean counters stopped any sophistication like that in 1950 Stevenage
 

Nulli Secundus

Well Known and Active Website User
VOC Member
VOC Forum Moderator
I am sure on some long gone British single( Ariel VH?) or even a BSA (god forbid!) there was a sliding shutter arrangement made of a tin plate with an oval hole riveted to the back of the chaincase with a bent up groove formed along the top and bottom and a sliding shutter with a shaft hole in it, very neat. I guess the bean counters stopped any sophistication like that in 1950 Stevenage
The Norton Commando has something along the lines of that description and it seems to work.
 

Marcus Bowden

Well Known and Active Website User
VOC Member
This is what Pat Wilson did in 1952 or 53 when building the trials Grey Flash (the only one) with the chain-driven timing side and sounds like a Velo so he told me I've had it since about 1975 but iit's coming together slowly with a lot of pushing from Vibrac.
BANANAMAN.

SHAFT SIZE HOLE IN SLIDING PLATE WITH RIVETED IN GUIDE PLATES
DSCF0883.jpg
 

b'knighted

Well Known and Active Website User
VOC Member
A good picture Marcus.
It also shows the relationship between the heights of the drain plug and the level plug showing that the intention was to have a dribble of oil for the bottom of the chain to run in.
Is there really such a problem when the oil is at the correct level?
 

vibrac

Well Known and Active Website User
VOC Member
A good picture Marcus.
It also shows the relationship between the heights of the drain plug and the level plug showing that the intention was to have a dribble of oil for the bottom of the chain to run in.
Is there really such a problem when the oil is at the correct level?
No but the Chain cam could be at 45 degrees from vertical (in either plane!) on a Trials section and you dont want oil on your trials tyre
 

ericg

Well Known and Active Website User
VOC Member
Similar set up on Pre unit Triumphs.
I suspect all British made machines with non unit engine-gearbox used a sliding disc to seal the chain case. Except Vincent apparently?
 

Sakura

Well Known and Active Website User
VOC Member
I am sure on some long gone British single( Ariel VH?) or even a BSA (god forbid!) there was a sliding shutter arrangement made of a tin plate with an oval hole riveted to the back of the chaincase with a bent up groove formed along the top and bottom and a sliding shutter with a shaft hole in it, very neat. I guess the bean counters stopped any sophistication like that in 1950 Stevenage
Why disparage BSA, undoubtedly the most successful motorcycle engineering company ever in the UK? Not only bikes but cars, machine tools, steels, mining equipment, arms, bicycles etc.
 
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