Primary leaking
- Thread starter koda
- Start date
- Status
- Joined
- Apr 15, 2009
- Messages
- 11,527
Could be bad seal at the crankcase? Not to bring up breathers... :mrgreen:
You may need a combination or number 9 and 11 seen here.
http://www.oldbritts.com/1972_g8.html
Things just seem to change on re assembly.
Because it is all sandwiched together at the central nut, things need to be flush. You need to sight the inner cover on the crankcase to determine shims needed at the central stud. A new or different inner cover gasket is a frequent cause of this affliction.
http://www.oldbritts.com/1972_g8.html
Things just seem to change on re assembly.
Because it is all sandwiched together at the central nut, things need to be flush. You need to sight the inner cover on the crankcase to determine shims needed at the central stud. A new or different inner cover gasket is a frequent cause of this affliction.
Well I do not think it is the crankseal leaking The crankbreather I installed from CNW stopped all and I do mean all engine leaks. or at least I thought it did . I wiil pop the cover off again and see if I have missed what you gents have suggested. Thanks for the help I will keep you posted.
- Joined
- Dec 10, 2008
- Messages
- 7,253
koda said:
The engine will not leak with that breather system as long as the engine is running.
It is possible to have a damaged crankshaft seal that will allow engine oil to leak into the chaincase if the bike has been parked long enough for the cases to become "wet-sumped" If that is the case you will see an increase in the oil level in the chaincase after it has sat for several days. Jim Comstock
- Joined
- Jan 18, 2011
- Messages
- 153
Having just replaced the primary chain on the Commando i noticed the wire from the alternator was loose in the grommet so i put a good blob of silicone on the cable before tieing it to the stator post, and this has stemmed a persistant leak it was suffering.
rvich
VIP MEMBER
- Joined
- Jul 25, 2009
- Messages
- 3,188
The O-ring seal is leaking around the perimeter of the case? Maybe the seal got damaged?
Someone else's idea from the this forum (don't remember who) but I adopted it...
Remove the O-ring, clean the groove, check cases for flush fit, shim as needed. Then put a small bead of silicone in the bottom of the groove, put the O-ring back in and assemble chain chase to just snug fit. Clean off any silicone that has been pushed out. Allow the silicone to set. Now you can tighten down the outer case.
I am not a big fan of silicone on engines, but since the oil in the primary does not circulate through the rest of the engine you don't have to worry about it coming loose and clogging an oilway.
Russ
Someone else's idea from the this forum (don't remember who) but I adopted it...
Remove the O-ring, clean the groove, check cases for flush fit, shim as needed. Then put a small bead of silicone in the bottom of the groove, put the O-ring back in and assemble chain chase to just snug fit. Clean off any silicone that has been pushed out. Allow the silicone to set. Now you can tighten down the outer case.
I am not a big fan of silicone on engines, but since the oil in the primary does not circulate through the rest of the engine you don't have to worry about it coming loose and clogging an oilway.
Russ
It can just as well be the super high tech felt seal behind the clutch hub is doing what it was programmed to do - leak. Get a clean rag, get it right under the primary inner case and up inbetween the bottom frame tube as near to the drive chain sprocket as you can. If you are using ATF it will probably show a pink red stain. If so that's coming from the felt seal on the mainshaft. It runs down the back of the inner case and forward 6"to near the front by the motor and drips usually onto the left header pipe.
There is a cure for this, late 850 Mk2's had the mystery part with a cupped lip on the inside seal plate. I got one and it works. Mystery is it has no part number and they are fairly rare.
Mick
There is a cure for this, late 850 Mk2's had the mystery part with a cupped lip on the inside seal plate. I got one and it works. Mystery is it has no part number and they are fairly rare.
Mick
Some good tips there to look at, but. I believe the correct shimming of the inner and outer primary case should leave approximately 20 thou clearance all around the join, with the rubber omitted for measuring. And the centre bolt nipped up. The rubber o-ring seal should not allow the cases to fully mate up, if it is still good, and if you shim to let the cases mate up with a good o-ring you can pull the centre in with the bolt and distort the cases. Also make sure the centre bolt is spaced to make the inner primary sit right when the outer nut is torqued up. Any clearance without the centre bolt done up and you need to shim.
Cheers Richard
Cheers Richard
Assuming it's leaking from the joint between the primary case halves, I've tried various techniques and this works best for me :
1. Use a new, Genuine Norton rubber sealing band. I've had pattern seals in a much softer rubber which compressed down to nothing and leaked like hell.
2. Clean & degrease the joint faces thoroughly. Fit the sealing band carefully, try not to stretch it and work it fully into the groove. No sealant at this stage.
3. Paint a thin film of non-setting jointing compound onto the rubber seal and the joint face of the outer case and leave for half an hour. My favourite is Wellseal which paints on with a brush, but blue Hylomar/Hermetite or similar would do just as well. Silicone gasket sealant works, but it's easy to use too much (goes everywhere!) or too little (still leaks...) and it's a pig to clean off when you next split the primary case.
4. Fit the outer cover and centre nut, make sure the cover is fully seated then tighten the nut up gently. Don't overtighten or you could distort the case. Leave it overnight to "settle", nip the nut up another 1/4 turn or so, put the oil in and away you go!
Mitch
1. Use a new, Genuine Norton rubber sealing band. I've had pattern seals in a much softer rubber which compressed down to nothing and leaked like hell.
2. Clean & degrease the joint faces thoroughly. Fit the sealing band carefully, try not to stretch it and work it fully into the groove. No sealant at this stage.
3. Paint a thin film of non-setting jointing compound onto the rubber seal and the joint face of the outer case and leave for half an hour. My favourite is Wellseal which paints on with a brush, but blue Hylomar/Hermetite or similar would do just as well. Silicone gasket sealant works, but it's easy to use too much (goes everywhere!) or too little (still leaks...) and it's a pig to clean off when you next split the primary case.
4. Fit the outer cover and centre nut, make sure the cover is fully seated then tighten the nut up gently. Don't overtighten or you could distort the case. Leave it overnight to "settle", nip the nut up another 1/4 turn or so, put the oil in and away you go!
Mitch
- Status
