G5 Oil Leak

[Ozmadman]

I stand corrected Janet, all that stationary whizzing around could cause a leak(s), something must be wrong if it is leaking that badly. Even mine with a leaky main seal only leaked a bit and then it stopped once the level dropped a bit but most of that was when it was stationary, on the side stand and not running

[starfield181]

Ok, Trying to get a bit more objective about the oil leak. I ran the engine yesterday morning and put the piece of cardboard in the picture under the bike. It was clean (well no oil stains anyway) and what is there accumulated in about 30 hours. The cardboard was pushed up against the centre stand and some oil had run of the back edge so slightly more actually leaked than shown in the picture and obviously some has been absorbed by the cardboard. Interested to know if this should considered a serious leak or 'they all do that sir'.

There is also a smaller pool of oil maybe 2 1/2" in diameter on the chaincase side right at the back, in fact so far back its almost beyond the extent of the engine. As a matter of interest, where does the engine breather vent too?

Tonight I placed fresh newspaper (run out of cardboard, times are hard) and I will measure the size of the oil puddles after 24hours. The engine has not and will not be run again until I have a handle on the level of static oil leakage. I had topped up the gearbox yesterday after it was run and the level has dropped a small amount, probably consistent with the puddle underneath.

Thanks everyone.

2016-02-24 19.45.00.jpg

[Ozmadman]

Oil running down the centre stand is usually the gearbox rear main seal leaking as the two gaskets that seal the casings are both nearer the RH (lever side)side of the box. the only way to check is have a look underneath as I mentioned in my previous post at the casing where the sprocket is. If there is clean oil there then there is your leak. Keep in mind though that the engine breather vents onto that sprocket so you may have some dirty oil present, As for the oil right at the back, do you have a full chain guard? if so oil can collect in the bottom of that from the engine breathing and drip out of the drain hole in the bottom of the guard. if you only have the top half of the guard then it usually sprays over the rear end of the bike by means of the rotating chain. Even so you shouldn't get that much, I get a couple of drips only after a long run. If you are getting as lot then your engine oil level must be going down as well. I did 156 miles on my one day visit to the Jampot Rally last year and didn't need to top up either oil

[starfield181]

After nearly another 24hours static, the bike has leaked the further amount of oil shown below. It seems to line up with the centreline of the bike, There was no fresh drip from the primary drive side.

Decided not to take it for a ride pending a deeper investigation into the likely source of the leak so the bike is now on the lift to get get a better look underneath and the outer timing side cover has been removed. Sadly there was no eureka moment, in fact it actually looked pretty good. The engine itself seems to be totally oil tight.

Examing the bike, the primary drive oil level was bit high as some came out when I removed the level plug. That is a bit odd as I don't quite see how you could overfill it so perhaps its 'acquiring' oil from elsewhere? Given that the chaincase oil is still very clean its unlikely to have come from the engine. On the other hand, maybe I just didn't have the bike on the level when I topped it up last. All I can do is monitor that point going forward. Not sure if it has any relevance, but the primary chain was too tight so has been adjusted. There is now little if any signs of oil leakage on the primary drive side as far as I could see and no drips from that area in the last 24 hours. The oil that previously leaked would seem to have run down the pressed steel plate that is behind the primary chaincase and was presumably part of the full rear chaincase when new, all I have is the top bit now. There is no oil on the back tyre (yet anyway).

DSC_3882.JPG

The bike is now resting on the lift with a clean bottom and clean paper underneath so any further drips and hopefully the source can be easily seen.

PeterF

[Ozmadman]

The only way and extra oil could get into the chain case is via the LH side crankshaft bearings as there is no seal there but that is highly unlikely unless you have a blocked breather?? Oil that is running down that small tin plate can only come from the gearbox seal or less likely the felt seal where the gearbox output shaft comes through into the primary casing but in that case you would loose oil from the case and no be seeing and increase!!. That oil looks quite clean to me so still reckon its coming from the box, maybe leaky gaskets, dripping into the lower frame and running out from a different place to where it is leaking from but that wont account fro oil on the tin plate. see pic (ignore the green o ring that was my mod)

[starfield181]

Thanks Paul,

Is the engine breather vent visible in your top picture?

PeterF

[Ozmadman]

Yes, see the picture. this mess was before my engine strip down by the way. click on the pdf file

[Ozmadman]

Here is another angle with the box removed. It is the hexagon nut (actually a long tube which screws into the crank breather stator) with the hole in it. The latest models had a different arrangement which just had a hole there as the stator was bolted secure by a different method

[starfield181]

Thanks Paul that's doubly helpful as it also answers another question - you obviously can remove the gearbox whilst leaving the engine in the frame.

It's beginning to look as though the vast majority of oil that has been leaking from my bike is coming from the kickstart shaft. Having let it stand for nearly 3 days that is the only place I can now detect a leak. My previous confusion about multiple oil leaks is I think caused by the fact that the oil actually runs inside the outer timing cover and then spreads all over the place. With the cover off it drops straight down onto the ex pipe. It such a tiny trickle I cannot believe the mess it created.

I started the engine up and ran it for 10 minutes earlier today and k/s spindle apart there is hardly a drip of oil. I plan to ride the bike with the cover off to make sure the diagnosis is correct. Next thing is to consider whether to try and replace the O rings or simply live with it. Not very confident about stripping gearboxes even though it looks as though only the end cover needs to be removed.

I guess it should stop leaking once the level drops below the spindle? If so I could be tempted to drain it to that level after a run and just top it up next time. As a matter of record, if the level was to drop to that point on a run, is the gearbox in danger or is there sufficient left to lubricate it adequately? Thinking back, that was about the level in the box when I first got the bike and the leaks only became apparent when I gave it a full service.

Thanks for everyone's input.

PeterF

[Ozmadman]

Next thing is to consider whether to try and replace the O rings or simply live with it. Not very confident about stripping gearboxes even though it looks as though only the end cover needs to be removed.

You can take the end cover off and replace the seal if you are careful. When you undo those 6 screws holding it altogether there is a tendency for the other section of the case to pull apart a bit as well so you have to be careful there. If you do go that route you may as well change the gear change seal and selector shaft seals as well as they are prone to leak. You can get modified seals (not the original o ring type) for the kick start and gear change (they are both the same seal) and then you will need to get the two small o rings on the selector shaft (the bit that the gear lever fixes to) I actually fitted two seals to my kick start shaft to cure a persistent leak (which it did!) it made the kick start a bit sluggish to return at first but after a few uses it was fine. Ok, to assist you... have a look at the picture attached, this is what the inside of that outer case will look like.

The bottom hole (the case is upside down)where the brass bush is where the seal(s) will go in for the kick start. (the kick start shaft will stay attached to the gearbox when you pull the cover off) You can put the seal(s) on the shaft instead of inside the bush if you want, this may be a better option to reduce the chance of damage to them. The stuff at the top is for the gear change (to replace the seal, the same one as the kick start one) take off the thin spring with the legs on it, the cup washer underneath will fall off.

The y shaped piece is the gear change pawl, this is attached to a cast piece of metal which is attached to the gear change shaft which goes into the casing ( so in effect it is all in one bit) it is held there by that thick spring, either give the shaft a good pull upwards to release if from the spring or prise the spring off the shaft and then the shaft will pull out, this is where the gear change seal is.

When you put it all back make sure you push the gear change shaft/pawl unit back into the clutches of that thick spring AND the Y shaped pawl is how it is in the picture and not inverted as you won't be able to select any gears then put the cup washer on top then the thin spring with the two ends located into the slots in the tin plate thing (use the picture for reference)

Finally, you will have noticed that the thin gear selector rod (that goes through the small hole in the gear change shaft) which is sticking out from the gearbox has two small o rings on it, replace them. Keeping everything in place, replace the gasket (using some sealer) and slide the cover back on and job done.

I guess it should stop leaking once the level drops below the spindle? If so I could be tempted to drain it to that level after a run and just top it up next time. As a matter of record, if the level was to drop to that point on a run, is the gearbox in danger or is there sufficient left to lubricate it adequately? Thinking back, that was about the level in the box when I first got the bike and the leaks only became apparent when I gave it a full service.
PeterF

All the gears are at the top of the box and these are notorious for gearbox problems if you run it low on oil, keep it topped right up to the limit and don't let it drop too far. Dropping it down to below the spindle is asking for trouble. It takes 3 pints to fill it up