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[Pict]

Hi again. My oil leak behind the gearbox sprocket was probably due to the complete lack of o-ring, but since I had bought the seal and spacer I replaced those anyway the refitted the sprocket avec o ring.

Yesterday evening when I undid the clutch centre nut it wasn't slack slack but it wasn't 55Nm tight either but I didn't give it any thought. It was tight enough. NOW when I tighten the (new) nut up anywhere near tight the clutch centre all but locks up (I can turn it, just, using both hands)that's not right now is it!?

If the new spacer behind the sprocket was not so deep as the old one would that be the culprit? I didn't think to check them side by side. If not that then what?

[grunda 12]

hi pict you may have answered your own question here i would stip it back down and have a look if i was you atb paul

[Pict]

Cheers Paul, suppose I was just looking for a bit of reassurance

[Pict]

It's the back of the clutch drum fouling the oil seal holder. The mainshaft doesn't seem to be through enough to the left so that the ends of the splines aren't proud of the seal adaptor. There isn't any discernible endfloat in the mainshaft and it turns freely enough. I don't suppose that there is anything else for it other than to have a look inside the gearbox. Any ideas? Maybe a bearing not seated properly? Someone has definitely been in about it judging by the blue Hylomar.

[Norm]

Pict,does the mainshaft spin freely with the clutch off, does the mainshaft sleve (with the sprocket on it) spin freely? If you pull and push on the sprocket does the sprocket have any movement in and out? If yes the bearing is loose in the housing, if not forget about the box as the problem. My tip is the clutch is going back too far on the mainshaft and hitting the inner primary/oil seal. If this is the case it will need a washer fitted to the mainshaft to prevent it from going back too far. Some have a circlip, some have a ring type washer, and some have nothing. It all comes down to how badly the shaft was machined in the first place some clutch hubs are a loose fit, others wont even go onto the shaft

[Pict]

Opened the gearbox and when the mainshaft nut is released the mainshaft can be pushed to where I think is 'right'. Back in the house now in front of Question Time and having a look at the parts list. I don't think I have a 'OIL THROWER, INNER Code: 111167' fitted... Do you think that missing is what is letting the shaft pull too far to the offside?

[Norm]

Pict, if that oil thrower/distance piece is missing that will certainly pull the clutch hub back against the inner primary by a couple of mm apart from the fact without it the high gear pinion is hard up against the bearing. I have not come across one of those missing but outer throwers yes. With sealed bearings or grease in the box you can get away without the outer one but with unsealed bearings and oil in the box the oil really pumps out through the bearing cap without the outer slinger

[Norm]

And getting back to your original statement about the missing "O"ring, I assume you are talking about the one in the sprocket nut, if this is the case, most of that oil leak between the mainshaft and mainshaft sleve usually occurs when the bike is on the sidestand

[Phil Ashbrook]

I recon you need a new clutch center , before mine went I thought the nut was slacking off but tightening it pushed it further down the shaft so as to collide with the oil seal cover plate , the cluch balls were shagged out as well , a new clutch center fixed it .

[simon]

I seem to remember that my old 51 machine had a (or I should say required a) washer or a spacer between the clutch centre and the shaft stop as without the clutch rubbed against the back of the case. I filed one up out of big washer. The important thing was to get the sprocket on the basket to align with the crankshaft sprocket. You don't want those two out of line.