tony27 Posted August 25, 2009 Report Share Posted August 25, 2009 Does anybody(Cope) know the thickness of the shims in the gearbox, about to strip mine to find some play & freshen up the motor & would help to have reference sizing to compare with Symptom is that if I lean bike to right(clutch side) on my workstand & rotate wheel or front sprocket if chain is off that it will lock as though in gear while in neutral, putting bike upright again disengages it, not sure about what happens if leant to the left as normally when oiling chain Quote Link to comment Share on other sites More sharing options...
copemech Posted August 26, 2009 Report Share Posted August 26, 2009 Does anybody(Cope) know the thickness of the shims in the gearbox, about to strip mine to find some play & freshen up the motor & would help to have reference sizing to compare withSymptom is that if I lean bike to right(clutch side) on my workstand & rotate wheel or front sprocket if chain is off that it will lock as though in gear while in neutral, putting bike upright again disengages it, not sure about what happens if leant to the left as normally when oiling chain Mmmm, no idea really! Main thing is if they are there! As the bearings are what the shafts really shim against, there should be some normal play, as it seems my countershaft (output) will move in and out just a bit, guessing .5mm max. For things to lock up suggests the engagement of two gear elements at the same time. That would tend to narrow things to the shift drum and forks or the shaft with two forks, countershaft I think if it were the transmission proper. Anyway, excessive sideplay in any of these should be apparent even with removal of the clutch side cover alone I would think, and duplicateable on the bench! Hopefully no one has been in there and displaced things in the past! Don't forget to ck the lickstart gear! Hope that helps, MC Quote Link to comment Share on other sites More sharing options...
tony27 Posted August 26, 2009 Author Report Share Posted August 26, 2009 Just started the pull down & only happens if leant to clutch side, turning hub by hand if leant away nothing happens but leaning towards me can feel gear trying to engage & then start to drive bike forward. My guess is that 1 of the shims has worn & lets a gear move just enough to catch the dogs on the gear next to it, they're only about 60p each so I'll probably just replace them anyway to be safe. Hopefully the bushes in the gears are okay & not letting them tilt. When I did the first set of main bearings the selector forks were good & so was the drum so I'm not anticipating problems there, would add greatly to the cost as forks are 40 odd pounds each & drum 80 odd. Will let you know findings once its apart & measured Quote Link to comment Share on other sites More sharing options...
tony27 Posted August 26, 2009 Author Report Share Posted August 26, 2009 Have engine out & everything apart from cylinder off, some end play in mainshaft 0.5-1mm max but none on output. Will take cylinder off & split cases at work tomorrow & do some measuring What should I be looking for kickstart gear wise, all looks good at first glance. Idler gear has a bit of play, 1-2mm at the most so will do bearing in that. No rounding or chips evident so far Quote Link to comment Share on other sites More sharing options...
copemech Posted August 27, 2009 Report Share Posted August 27, 2009 Have engine out & everything apart from cylinder off, some end play in mainshaft 0.5-1mm max but none on output. Will take cylinder off & split cases at work tomorrow & do some measuring What should I be looking for kickstart gear wise, all looks good at first glance. Idler gear has a bit of play, 1-2mm at the most so will do bearing in that. No rounding or chips evident so far Well, it sounds to me that you have a good idea what to look for, yet not sure where exactly you will find it. Is seems there are some thickness measures on the shim washers in the parts book listings, maybe not enough to guage everything. Hopefully it will become more evident when inspected. As far as the kicker gears go, I seem to recall some weird buzz when the bike was leaned right and Ryan sent me a gear. I think it was the kickstart pinion M151, yet too many years have passed. All i recall is that it fixed the problem and I never really seen the machining issue with it. Keep us posted ! MC Quote Link to comment Share on other sites More sharing options...
tony27 Posted August 27, 2009 Author Report Share Posted August 27, 2009 (edited) They say confession is good for the soul so here goes ..... Turns out when I did the mains & seals about 2 years ago I put 1 of the washers for the kickstart idler gears(#M163) on the wrong side of the casing, there was 1 of them plus the #M071 washer at the end of the output shaft meaning the 1ER pinion was 1mm closer to the 4EME pinion than it should have been, when I first split the cases & turned the shaft I could stop the problem by lifting the right fork slightly Putting washers back in correct positions removed most of the play in the kickstart idler & stopped the gears trying to select by themselves The gearbox shims look okay with not much wear only polishing where meet, the bushes in the gears have some play but not excessive. Forks are polished & selector drums still has the hard anodising in the slots so shims & washers will only be a precaution The main bearings are black as normal & noisy but already have them, transfer ports are also black- both in the cases & cylinder almost as though some burning charge is entering them(not logical just a theory). Haven't measured piston yet as I didn't bring correct micrometer home but I'm thinking it may as well be replaced after 5 years, bore looks good All in all the motor has very little wear & the amount a full freshen up is costing in parts is tiny compared with how much enjoyment I've gotten out of the bike so far Edited August 27, 2009 by tony27 Quote Link to comment Share on other sites More sharing options...
copemech Posted August 28, 2009 Report Share Posted August 28, 2009 They say confession is good for the soul so here goes ..... Turns out when I did the mains & seals about 2 years ago I put 1 of the washers for the kickstart idler gears(#M163) on the wrong side of the casing, there was 1 of them plus the #M071 washer at the end of the output shaft meaning the 1ER pinion was 1mm closer to the 4EME pinion than it should have been, when I first split the cases & turned the shaft I could stop the problem by lifting the right fork slightly Putting washers back in correct positions removed most of the play in the kickstart idler & stopped the gears trying to select by themselves The gearbox shims look okay with not much wear only polishing where meet, the bushes in the gears have some play but not excessive. Forks are polished & selector drums still has the hard anodising in the slots so shims & washers will only be a precaution The main bearings are black as normal & noisy but already have them, transfer ports are also black- both in the cases & cylinder almost as though some burning charge is entering them(not logical just a theory). Haven't measured piston yet as I didn't bring correct micrometer home but I'm thinking it may as well be replaced after 5 years, bore looks good All in all the motor has very little wear & the amount a full freshen up is costing in parts is tiny compared with how much enjoyment I've gotten out of the bike so far Good job then! Hopefully you will not have my wife over for cleaning while everything is laid out in proper order! It all varies you know, but I often wonder if one would be better off with a light hone job and a move up on the piston from say A to B. This stuff requires some specialty equipment for proper measures and honing, but then again, if the bore looks good, stuff a new piston in it and go! Only reason I question it is some just seem a bit rattely. Oh well? So did you figure out the bearing thing? Now someone says the sealed bearings not from Sherco may hold grease rather than oil? Personally, this gets to the point where I just order the factory parts when needed. Life is too short! Quote Link to comment Share on other sites More sharing options...
tony27 Posted August 28, 2009 Author Report Share Posted August 28, 2009 Brought my telescopic gauges home & just realised the piston should be 76mm so I've got the wrong micrometer in my bag, lucky measuring 1mm past is still on the scale I have the sealed bearings from sherco to fit, they have a poly urea thickened grease in them according to SKF's catalogue. The specs give a 7500rpm limit due to the seals which would be as a constant speed rather than a peak so everything stacks up Bike wasn't rattly but there are a couple of lines on the piston, only slightly discoloured rather than scuffed. I'm just thinking while its apart I might as well replace it & the beta importer owns me a favour, pistons are exactly the same as in the 270 beta Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.