I find that the chain case on my Dominator 99 is filling with oil after a hard run and leaks when I stop until I drain off the excess. I gather from the site the crankshaft oil seal is a known problem with the model. I was wondering what is involved in changing the seal. Can it be done in place by removing the alternator and clutch or is it a more complicated job?. I did a search and although I know I have seen some reference to the seal I cannot find it now. Any help would be appreciated.
Some time back I was having trouble with a misfire after a run of about ten miles. I changed all the electrical components including the coil but the problem persisted until I started to use a petrol additive. After a couple of months the problem returned until one day the bike just stopped. I checked everything and was getting a spark and fuel. In desperation I changed the coil and it started first kick. The coil was mounted at the rear of the engine over the carb so I changed the position and now the miss has disappeared again. Iâm keeping my fingers crossed that the coil was overheating and that I have finally found the problem.
Cheers,
Peter
You should be able to remo…
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Colin, Thanks for the info…
Colin,
Thanks for the information on the oil seal, hopefully it will be an easy fix. I replaced the oil pump about a year ago to sort out a wet sumping problem which it seems to have done. As for the breather, how do I go about checking this. My understanding was that it was only accessable by stripping the engine?. BTW there has always been a leak into the case but recently it has been bad enough to cause clutch slip if not drained quickly.
Thanks again.
Peter
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Peter, This is how I would…
Peter,
This is how I would change the drive side crankshaft seal on a 99 Dominator.
Disconnect the foot brake, remove the outer primary chain case cover, put the bike in gear and reconnect the foot brake with the adjusting wing nut lock the back brake so that the alternator rotor nut can be removed, remove the alternator stator there is usually enough slack in the cable to get it off and lodge it up near the magneto, pull the alternator rotor, watch out for the key, put the rotor in the stator so that the magnetisim is not lost, disconnect the primary chain noting the direction of the split link, pull the drive sprocket keeping an eye out for the key, remove the alternator aluminium casing.
Give the area of the seal a wipe with a rag, find two self tapping screws not too big on the diameter but failry long, find the drill size for the screws and carefully drill two holes 180 deg apart in the metal casing of the seal, carefully screw in the self tappers, not too far, pull out the seal it might be possible to do this by hand or with pliers, give the area a good clean, check that there is no dirt in the main bearing, inspect the seal running surface of the crankshaft, dress any burrs as required, check/clean the crankcase where the seal fits.
To fit the new seal, lubricate the crankshaft, note that the seal fits with spring facing the engine, carefully push the seal over the crankshaft and be careful not to damage the lip of the seal, push it as far into the crankcase as it will go by hand, with a soft hammer tap it home keeping it square and until flush with the crankcase.
Reassemble in reverse order, it is good practice to put a little sealant on the alternator casing screws, when fitting the alternator stator make sure that the air gap has sufficient clearence and it is uniform.
Tony
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Many thanks Tony for such…
Many thanks Tony for such detailed instructions. I will order the parts and get stuck in as soon as they arrive. Hopefully that will sort out yet another problem.
Peter
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Previously wrote: You shou…
Previously wrote:
You should be able to remove the old oil seal as you suggest. A small hole drilled in the seal and a corkscrew might help get it out. Make sure you remove any burrs from the new seal before knocking it in place.
What worries me more is how you are getting so much oil in the chaincase. The Norton is a dry sump engine, so little oil should be in the crank case unless oil is going past the oil pump when the bike is not being used, service the oil pump as suggested in the manual to fix this one. Also make sure the breather is working properly.
The sump should never be full enough to allow oil to be at the seal level as it is a dry sump motor as stated above. There has to be another reason why the level in the chaincase is rising. You are sure that it is engine oil and not gearbox oil draining into the chaincase? If the breather pipe on the oil tank is kinked (read closed) it may cause the sump to fill up as the oil pump will not scavenge adequately.
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You should be able to remove the old oil seal as you suggest. A small hole drilled in the seal and a corkscrew might help get it out. Make sure you remove any burrs from the new seal before knocking it in place.
What worries me more is how you are getting so much oil in the chaincase. The Norton is a dry sump engine, so little oil should be in the crank case unless oil is going past the oil pump when the bike is not being used, service the oil pump as suggested in the manual to fix this one. Also make sure the breather is working properly.