Engine oil sudden leak

Previously roger_deadman wrote:

Previously philip_gilliver wrote:

I have just ridden 1 mile each way to get an mot on my model 50. On the return trip, I was aware of a blue smoke trail. My engine has never even emitted a whisp of oil smoke. When I stop at home, oil was spurting from behind the primary chain case and luckily didn't quite empty the oil tank. I re started the engine and oil pumped out again. On inspection, it is returning as it should to the tank ( what oil was left anyway). I would be most grateful for any help. The engine sounds very sweet and mechanically quiet. The bike has not been ridden over winter but started weekly with no issues. There is a slushing sound and an expulsion of oil even when kicking the engine over without ignition on. Is there a crankcase breather valve stuck or something similar? It rode fine to the testing station, no smoke, no oil leak.

please help!!!

.hi philip sounds as if the engine oil has leaked into the crankcase via the oil pump quite a common thing to happen drain the crankcase refill oil tank check oil level in primary drive as running with a sump full of oil it may have forced through main bearings its a good idear to check oil tank level if the bike has not been started for a while

regards roger

Hi Roger, thanks for your speedy reply. The oil level was spot on prior to my ride today. The 1 mile to the testing station was fine. No oil leak on arrival. Where is the oil escaping from?

Previously michael_sullivan wrote:

I was thinkingthat the only place the oil can escape from the crankcase into the primary chaincase is through the drive side main oil seal but then I thought about the crankcase vent. You said that it was spurting. This would indicate too much oil in the crankcase. Has the bike been standing? Maybe it was just sumped. Have you done any work on it lately? Is it possible that the connections fron the tank to the crankcase have been reversed?

After the ride to the MOT how was the oil level in the primary?

There is a crankcase vent valve of sorts on the primary side of the crankshaft. This is a rotary valve type ventthat when open the crankcase pressure is vented out of the crankcase, through a tube, onto the drive chain. Was that where the spurting was happening?

Mike

Hi Mike, thanks for your very helpful reply. Oil level in primary was ok and still is. I've just removed sump plug and oil poured out. I half filled the oil tank and fired it up- no oil spurting out , but although oil is emerging from the return tower nice and fairly dribbley the tank oil level is slowly dropping. I did replace the oil feed pipe hoses and gaskets between Union and crankcase along with a new rocker feed t-piece( yes it is the right way round and has an oil feed groove machined in it) . I thought when I did this work that there wasn't much oil in the tank. When I had fitted the new parts , I refilled oil up to level transfer . Obviously the existing oil had sumped hence today's problem but why isn 't enough oil returning to maintain the correct level?

I really appreciate your help.

Previously anthony_bolton wrote:

Previously philip_gilliver wrote:

I have just ridden 1 mile each way to get an mot on my model 50. On the return trip, I was aware of a blue smoke trail. My engine has never even emitted a whisp of oil smoke. When I stop at home, oil was spurting from behind the primary chain case and luckily didn't quite empty the oil tank. I re started the engine and oil pumped out again. On inspection, it is returning as it should to the tank ( what oil was left anyway). I would be most grateful for any help. The engine sounds very sweet and mechanically quiet. The bike has not been ridden over winter but started weekly with no issues. There is a slushing sound and an expulsion of oil even when kicking the engine over without ignition on. Is there a crankcase breather valve stuck or something similar? It rode fine to the testing station, no smoke, no oil leak.

please help!!!

Dear Mr Gilliver,

I had exactly the same problem with my 650ss about 20 years ago. I was living in Germany and because I could not afford the insurance my bike had not been started for over a year. Upon giving it a trial start oil gushed out of the primary chaincase. I reasoned that because the oil tank was empty that its contents had drained down into the crankcase and that my drive side oil seal was faulty.

That was not the case upon inspection. Essentially if the crankcase is full of oil upon start-up it goes via the rotating crankshaft into the primary chaincase.

Just drain the oil out of the crankcase and primary chaincase and refill the oiltank to the required level and carry on. Because of this I fitted a small stopvalve on the oil supply line from the oil tank to the engine. This is not a practice to be taken lightly - I always remember fuel on, oil on - I guess I have been lucky.

Regards,

Peter Bolton.

Hello and thank you for your reply. This morning I stripped off the oil feed pipes and discovered a small flap of silicon sealant partially blocking the return hole on the union at the base of the two oil-feed pipes. It had obviously squashed out when I refitted them. My smile of joy at thinking I had sorted it soon turned to yet more frustration. After making a new gasket and reassembling everything dry I again drained the sump , refilled half a tank of oil and started the bike and let it tick-over expecting to see a nice healthy spurting of oil returning to the oil tank. After some minute to a minute and a half a very minimal dribble came from the return tower and the oil level began to drop. The feed and return pipes are clear of any debris/obstruction. The sump was filling up again and to make things worse, the sump drain plug hole threads have stripped. Can I get an oversize sump plug.? Could the oil pump have given up? Incidentally, when I made the gasket, I made it using the oil pipe union face as a template. On fitting the gasket to the crankcase, the holes were nowhere near correct so I made another to fit the feed/return holes exactly and then fitted the oil pipes .

Grateful thanks to anyone who can help or advise me.

Previously Paul Knapp wrote:

Hello Philip, Since you say you have used silicon in the engine (a definate NO NO)I think it's time to remove the timing cover and pump and see if there isn't anymore bits floating aroundblocking the oil ways, particularly the scavenge side!

Good luck.

Hello Paul, the only silicon I have used was a small amount to hold the oil junction block gasket in place. My next move is as you suggest, an inspection if the oil pump and any oil ways that at visible when the pump is off. Then it's the sump plug job.

Thank you for your comments.

Previously philip_gilliver wrote:

Previously Paul Knapp wrote:

Hello Philip, Since you say you have used silicon in the engine (a definate NO NO)I think it's time to remove the timing cover and pump and see if there isn't anymore bits floating aroundblocking the oil ways, particularly the scavenge side!

Good luck.

Hello Paul, the only silicon I have used was a small amount to hold the oil junction block gasket in place. My next move is as you suggest, an inspection if the oil pump and any oil ways that at visible when the pump is off. Then it's the sump plug job.

Thank you for your comments.

Hello and thank you to all who offered advice regarding my bike issues. I've stripped the timing side, oil pump etc and when applying my air line to the oilways, a lump of crud shot from the sump drain hole like a pea from a pea-shooter. After careful reassembly and addition of oil I started up and after a few seconds, got a really good return oil flow. After a ride of 20- odd miles yesterday, observing no blue exhaust smoke and a lovely strong and quiet engine, I parked up and on inspection this morning, no oil leaks! I'll drain the oil and fill up with new oil today.

Once again my very grateful thanks to you all.

Phil