rampant rivet Posted January 5, 2014 Share Posted January 5, 2014 Ok having got the clutch thing under control I noticed a lot of end float in the main driveshaft coming out of the gearbox so.... how to get the gearbox out ? well first of all you have to dismantle the rear end of the bike :undecided: Quick wash off to get rid of lots of crud then get stuck in At first glance things look ok no sign of wear on the bronze thrust washer so what caused the end float ? quick check in the manual and I realise the concave steel washer is missing altogether :-( Does anyone have a spare washer knocking about please ? Also after stripping out all of the gears and shafts the main gear bearing is rough so will need to be replaced, other than that it looks like it hasn't done much work all I need now is to remember how it all goes back together :nut: Quote Link to comment Share on other sites More sharing options...
rampant rivet Posted January 6, 2014 Author Share Posted January 6, 2014 New bearing arrives tomo clutch plates arrived today so clutch is sorted :-D it seem that the missing washer is not unusual so I think I'll shim the end of the shaft to take out most of the slop. Quote Link to comment Share on other sites More sharing options...
79x100 Posted January 6, 2014 Share Posted January 6, 2014 I thought that I had one, but I can't find it, sorry. They seem to have appeared in the parts book around 1940 but few boxes seem to have one in and often it won't fit. Does your box have an 'H' stamped on it anywhere ? There is an odd reference in the factory ledgers which makes me wonder if there is a connection. You can tighten things a little by using something like 'Yamabond' instead of a paper gasket. Where are you thinking of shimming ? Outside of the mainshaft bearing ? How much end-float have you got ? Quote Link to comment Share on other sites More sharing options...
rampant rivet Posted January 7, 2014 Author Share Posted January 7, 2014 I aim to shim between the main bearing and the case of the gearbox to reduce the travel out toward the clutch side of the gearbox, before stripping the box I had over 1/8" of movement I think if I shim anywhere else then it will push the shaft further out which may mean the clutch rubbing on the chain case again. Quote Link to comment Share on other sites More sharing options...
rampant rivet Posted January 7, 2014 Author Share Posted January 7, 2014 Well the gearbox is back together , well almost as the kickstart pawl was showing signs of wear and needs replacing plus I have 1st gear a neutral and three 4th gears :nut: looks like somethings not quite right ! have added that shim in front of the main bearing and it as taken up some of the play will have another go at it tommo. Quote Link to comment Share on other sites More sharing options...
79x100 Posted January 7, 2014 Share Posted January 7, 2014 I'd be a bit worried about shimming behind the sleeve gear bearing, especially as there is no corresponding shim behind the layshaft bearing. The Convex washer used by Norton pushes the mainshaft tight to the sleeve gear, with end float being controlled by the bronze thrust washer (yours does indeed look pretty well unworn). Although the parts books always refer to the smallest gear on the layshaft as 'layshaft 4th', it's really layshaft 1st, 2nd and 3rd as it takes the drive in the lower gears. In 4th, the sleeve gear is locked to the mainshaft. It sounds as if the fact that your sleeve gear has now been positioned inwards might be stopping the mainshaft third from disengaging from it. Thin shims between mainshaft 1st and the small mainshaft bearing would get chewed up so I'd be inclined to try shimming behind the bearing in the inner cover. This will indeed push the clutch outwards but it will be where it is supposed to be. The chaincase can be adjusted and in fact moving the whole thing outwards will keep it away from the final drive chain and there is often too little clearance there as well. I haven't actually had to try this so usual disclaimers apply. Quote Link to comment Share on other sites More sharing options...
rampant rivet Posted January 9, 2014 Author Share Posted January 9, 2014 Gearbox sorted all ok, just waiting for the kick start pawl and a couple of bolts from Russell motors before it can all start to go back together :-D Quote Link to comment Share on other sites More sharing options...
rampant rivet Posted January 19, 2014 Author Share Posted January 19, 2014 Did 5 miles on the bike today and all seems ok with the box, at least it changes gear easier plus there seemed less false neutrals than before thanks for all help and advice. RR. Quote Link to comment Share on other sites More sharing options...
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