colinf Posted July 25, 2021 Report Share Posted July 25, 2021 Hi all, in the process of rebuilding the 191 engine.I've just gone through all the packs of seals and "O" rings to identify them all and have a couple of queries. The "O" ring set ( or the O rings with full gasket set ) comprises of 5 rings. The two large ones are No.54 on the engine illustration in the parts book (260-011) ,the smallest is No.20 on the gearbox illustration (111-028-1) which leaves two 25mm ones. One of these is No.17 on the gearbox illustration (111-025-1) but i can't see what the other one is for.......probably missing something obvious! The other problem is with an oil seal ( part No. 160-031, 14x20x3 ). This is No.45 on the gearbox illustration.I assumed this fits over the left hand end of the mainshaft and inside the outer end of the sleeve gear.The inside diameter is a good fit over the mainshaft but i don't think the outside diameter will fit in the sleeve gear. The seal O/D is 20mm but the I/D of the sleeve gear is 18mm! Again ,i could be missing something obvious! Any suggestions would be appreciated. Quote Link to comment Share on other sites More sharing options...
lorenzo Posted July 25, 2021 Report Share Posted July 25, 2021 (edited) Hi - The "spare" "O" ring 111-025-1 is for the crankshaft sprocket spacer (the crank seal sleeve). The sleeve gear seal 160-031 is correct at 14 x 20 x 3 - has the old seal been removed ? If your sleeve gear is 18mm. i.d. with 2 needle roller bearings, then the oil seal should be correct. This is originally a metal-cased seal - you will probably find that when you remove the old (rubber) seal it will leave the metal case behind, thus appearing to be just 18mm. Had me fooled the first time, too....... HTH Edited July 25, 2021 by lorenzo clarity 1 Quote Link to comment Share on other sites More sharing options...
colinf Posted July 25, 2021 Author Report Share Posted July 25, 2021 Thanks Lorenzo, I was hoping it was my eyesight but I don't think the remnants of a seal are there.I've tried feeling for an edge with an engineer's pick but can't feel anything.There is a slight bevel on the inside of the threaded end of the sleeve gear but otherwise the I/D of the sleeve gear is 18mm all the way through.Unless there was a recess for the seal I don't see how a 20mm seal will fit? Quote Link to comment Share on other sites More sharing options...
lorenzo Posted July 25, 2021 Report Share Posted July 25, 2021 Colin - As purchased, was this a complete (running) engine, or was it already dismantled ? Does the mainshaft have needle roller bearings ? The sleeve gear you have appears to be an earlier variant, which would have had 2 bronze plain bushes..........and NO oil seal..... It doesn't belong on a 191. Quote Link to comment Share on other sites More sharing options...
colinf Posted July 25, 2021 Author Report Share Posted July 25, 2021 I bought the bike about 9 years ago, it was in bits and about 90% "complete".I seem to remember that the vendor and his mate bought two bikes.It had crossed my mind that something might not be right, although the gearbox assembly was all together with both shafts assembled "as removed". The mainshaft has the two needle rollers which I've changed.Do you know if the sleeve gear is fundamentally the same other than the seal? The sprocket,nut,spacer etc all fit.Just wondering if I could machine a 20mm diameter recess and fit the seal? Quote Link to comment Share on other sites More sharing options...
lorenzo Posted July 25, 2021 Report Share Posted July 25, 2021 (edited) Hmmmm....... On 5-spd. Sherpas, the early type sleeve gear bushes were replaced from mod. 124 onwards with needle roller bearings and the 20mm. o.d. seal #160-031 and this arrangement continued to the end of production as far as I know.. I've dug out a mod. 124 sleeve gear so you can see what yours should look like: (ignoring the worn sprocket splines) .. As far as counterboring your existing sprocket,goes, it looks to have suffered some significant scoring to its bore. If your new needle roller bearings are to enjoy a worthwhile service life, the bore needs to be very smooth. (see above). To save yourself lots of further grief, you may do well to check off all the other gearbox parts against the parts book; some earlier (or later) parts will interchange and work, many will not. Who knows what mechanical mischief it may have suffered in the last 40-odd years ? HTH Edited July 26, 2021 by lorenzo 1 Quote Link to comment Share on other sites More sharing options...
colinf Posted July 25, 2021 Author Report Share Posted July 25, 2021 I'll check with in motion tomorrow on the off chance.They do list new gearbox components.I'll let you know Thanks for the info, a great help. Quote Link to comment Share on other sites More sharing options...
colinf Posted July 26, 2021 Author Report Share Posted July 26, 2021 New sleeve gear on its way courtesy of Pete at In motion. Fingers crossed that there aren't anymore surprises. Quote Link to comment Share on other sites More sharing options...
199 Enduro Posted July 27, 2021 Report Share Posted July 27, 2021 Pete is the best. Quote Link to comment Share on other sites More sharing options...
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