lorenzo Posted February 24, 2020 Report Share Posted February 24, 2020 (edited) One for the cognoscenti, maybe........ Does anyone have any thoughts/experience regarding improving the longevity/durability of sleeve gear bronze bushes ? This applies to models 27/49 and 80 with 14mm. mainshaft nose (bushes #111.047) and later models 91/92 with 15mm. shaft (bushes #48.11-047). I've dismantled a number of engines each of which shows wear to these bushes, characterised by a step in the outer bush bore, where it overhangs the end of the mainshaft. I have to wonder if there is a particular reason for the bushes to be fitted flush to the outer end of the sleeve gear, or whether it was simply a matter of production expediency......... Edited February 24, 2020 by lorenzo add missing text Quote Link to comment Share on other sites More sharing options...
feetupfun Posted February 24, 2020 Report Share Posted February 24, 2020 What is the problem with the bush going right to the end? One thing I do know is that I couldn't source the right size bushes for a M85 sleeve gear last year so I bought bushing material with a smaller ID and bored it to size once it was in place in the sleeve gear. Haven't tried the motor yet. I've always wondered why some 5 speed motors have needle roller bearings there and some have sleeves. Quote Link to comment Share on other sites More sharing options...
lorenzo Posted February 24, 2020 Author Report Share Posted February 24, 2020 (edited) 1 hour ago, feetupfun said: What is the problem with the bush going right to the end? One thing I do know is that I couldn't source the right size bushes for a M85 sleeve gear last year so I bought bushing material with a smaller ID and bored it to size once it was in place in the sleeve gear. Haven't tried the motor yet. I've always wondered why some 5 speed motors have needle roller bearings there and some have sleeves. The problem is that a part of the outer bushing is not acting as a bushing........The effective length is shortened, just where it's most needed. It's a M85 that I'm hoping to complete first. - this should have the 15mm. bushes. (and I haven't been able to obtain replacements, either). Needle roller bearings replaced p.b. bushes on models 124/125 onward. Presumably to correct the rapid wear rate of bushes......... and the mainshaft nose in that case is yet another different diameter to the 14/15mm ones it replaces. Edited February 24, 2020 by lorenzo missing text 1 Quote Link to comment Share on other sites More sharing options...
feetupfun Posted February 25, 2020 Report Share Posted February 25, 2020 There is nothing stopping you fitting the new outside bush further in from the end Quote Link to comment Share on other sites More sharing options...
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