I started changing the clutch today. When removing the plates, I noticed the clutch basket has a bit of a wobble. I assume this needs a new bearing? I haven't removed it yet.

Anyway, I pulled the release shaft out(I think that's what you would call it) from the centre of the basket. When I removed this I noticed there was coolant in there. I haven't noticed the bike getting through any coolant, but the gearbox oil was fairly grey and dirty. Has anyone got any ideas where the coolant would be leaking from?

Probably getting in through the water pump shaft/seals....or at least it was on mine.

Rich

No, I don't think so. The coolant that was on the release shaft was clean. Maybe some leaked in there when I took the clutch cover off, but I can't see how it got inside that tube, as such. Is there any water ways that run around that area? I can't think of any.

There is always a little coolant retained in the passages within the clutch cover and around the pump. It is possible that this leaked into the clutch as you removed the cover?

From what you have said, the coolant would have mixed to a nice mayonaisse colour, if it found it's way into the gearbox when the engine was running. I would agree with KNMK1, it's probably found it's way in there during dis-assembly, thus still identifiable as mixed coolant, IMO.
Mike

It may have gotten in there when I removed the clutch cover, but the water pump is the opposite end of the cover and the cover came away easily. The oil was very grey, but I put the wrong oil in 2 changers back, which made the clutch slip, so I put it down to that. I take it the only way coolant can get into the gearbox is through the water pump seal? This was replaced about 18 months ago.

xstian81 wrote:It may have gotten in there when I removed the clutch cover, but the water pump is the opposite end of the cover and the cover came away easily. The oil was very grey, but I put the wrong oil in 2 changers back, which made the clutch slip, so I put it down to that. I take it the only way coolant can get into the gearbox is through the water pump seal? This was replaced about 18 months ago.

Where is the end of the gearbox breather pipe that comes out of the back of the gearbox?
Dangling underneath invites water to get sucked back up the pipe into the g/box, and milky way g/box oil.
Mike

It was definitely coolant, it was pink. I'm going to change the water pump seal just to be sure, but is that the only way water can get into the gearbox?

I've also noticed the balance shaft is loose. I replaced the bearing where replaced about 18 months ago, but the whole shaft can be moved in and out, about 5mm. I don't mean up and down and side to side, but if you get hold of the cog on the end and pull the shaft will come out about 5mm. I'm going to take this out when I get a chance to have a look.

The other thing is the clutch basket bearing is worn. This was also replaced about 18 months ago. Would the water contaminated oil cause this to wear so quickly or is there something else? The bush that sits in there as well looks fine, no groves. If I measure this, does anyone know the size it should be?

The water pump seal would be the only logical route in for uncontaminated coolant.
Some limited float on the balance shaft might be expected, but what you described seems excessive.
Isn't there a locking tab washers or plate that locks the shaft in place, from memory.
Contaminated oil will not work as well.
Again, where is the end of the breather pipe, if thats sucking gritty puddle water back into the g/box that'lle take out bearings in a thrice.
Mike

The breather pipe exits under the swing arm by the dog bones. I suppose it is possible to have had some water sucked up that way. I'll move the breather to be on the safe side.

I thought the breather pipes exited into the air box............as on the AR.

The carb pipes exit below.

This differently comes out under the swing arm. It's routed in well so looks like it should go there. I think I'm going to move it anyway. I'm going to strip out the rest of the parts tomorrow, so I can see what's going on with the balance shaft.

You can route both the gearbox breather and the carb breathers into the air box but NOT the overflow pipe.
I normally pop a used in line filter on them as well, just an additional line of defence.
Mike

A quick update on this. The washer on the balance shaft was put in the wrong way around. This meant the shaft could float about and has rubbed on the clutch cover. This, I assume is why the gear oil has been coming out grey and why the clutch bearing is shot.

Now I have had a chance to think about this, although what I have written above is true, it can't have been the washer that has allowed the shaft to rub on the clutch cover. The bearing on that side retains the shaft. So even it loose the shaft could only move towards the magneto. The bearing on that side is located by two tabs, so that cant be in the wrong place, unless it is no seated properly, but it all looked ok.