I've discovered that if I pull the clutch lever in about half its travel with the box in neutral, turning the back wheel also tries to turn the clutch body as if the box was in gear (but slipping if you see what I mean). When I turn the back wheel with the clutch fully released, it's quite free and there's no tendency for the clutch body (ie mainshaft) to turn.
I do remember that before I stripped and rebuilt the box, that if I pulled the clutch lever when the engine was running, the back wheel would turn - effectively the same phenomenon. There was the normal slight tendency of the back wheel to turn due to drag from the gearbox oil with the clutch released. The bike rode well and changed gear with no problems on the few miles I rode it before rebuilding it over the winter.
I have fitted new bearings, bronze thrust washer and sleeve gear rollers and the gearbox seems to work perfectly well. There is minimal end float on the mainshaft.
This has me a bit puzzled as I can't see what connection there could be between the mainshaft and sleeve gear when the box is in neutral, and especially how operating the clutch could cause this. It's my first experience with the laydown box although I had several bikes fitted with the upright model many years ago, as well as decades with the AMC Commando version.
Any suggestions?
Bent lift perhaps ?
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Maybe why
When clutch is pulled, the rod pushes clutch and mainshaft to the left. This gives an axial force between mainshaft and sleeve gear. The force with half drawn clutch is somewhere in the region of 150LBS. When the rear wheel is rotated, axial friction between mainshaft and sleeve gear will try to rotate the clutch. With new parts friction can be a bit more before it is run in. Unless drag is excessive, I believe it's a normal behaviour.
Just guessing.
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I think you may have it Mikael
That makes a lot of sense. It's also probably the case that oil has drained away from the thrust bearing etc so increasing any tendency for this to happen.
I'll stop worrying!
BTW Richard, I've always felt that the mushroom head (with fully screwed down pressure spring pins) is a far better arrangement than the AMC box arrangement with more or less point contact and often futile attempts to even out the lifting by adjusting the screws.
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Mikael is correct in…
Mikael is correct in assuming an axial load exists between the sleeve gear and main shaft when the clutch is disengaged. With the clutch half out the main shaft is also partI ally connected via the clutch to the engine. Hence the greater resistance when turning the rear wheel. When the clutch is completely disengaged, the main shaft is no longer trying to turn the engine.
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Learned something
Well done gents - I've learned something from this and it makes sense.
Ian - I agree with you completelay on the ease of settling up the Norton clutch - I once offered to help a friend with his ( the T - word ) clutch thinking it would be a snap. I spent a long time in Swash Plate City !
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cam plate
hello I had a same problem and found it was the cam plate roller under side of the box allowing the cam plate to move from side to side without selecting and it also moved forward off its spline sometimes making it hard to select first gear So have a look in this area, may or may not be the problem it time for elimination and find what it is, yours anna j
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Hi Ian -
Just thinking out loud here - it's been a few years since I've had my box apart. Is it possible that the clutch is not lifting squarely ?
I wonder if the lifting foot at the end of the clutch rod is capable of tilting the pressure plate if the head is not square with its shaft - ??