I have purchased a Peugeot Kisbee 50cc 2013 as a non runner project with 4000 km on the clock , I have stripped it down to find the crank bearing on the variator side has failed , depositing bits of metal into the sump oil, With only 4000 km on the engine there is no obvious wear to the bore and piston, Can I get away with new bearings and seals or is it likely that some fine metal could of found it's way into the big end bearing The other option is replacing the crank with an aftermarket part but it is not that straight forward as although the engine is a GY6 139QMB it has an -E on the end with leads to some differences the first is the gudgeon pin on my scooter is 10mm in diameter, non OE cranks have a 13mm gudgeon pin so I would also need to change the piston ( the oil pump drive is the same 16T) , Other differences include 71mm valves , and the cam carrier is part of the cylinder head
that should be under warrenty surely? if you clean everything you should get all the metal out, but i myself wouldnt risk it. parts are dead cheap for those engines.
They don't make an aftermarket crank that accepts the 10mm gudgeon pin for the Peugeot GY6 139QMB-E engine so it's a choice of a genuine crank costing £130 if I want to keep the same piston , or if I go for an aftermarket crank then I will also need a piston, I think I'll take the chance of a new set of bearings
you an use a custom bearing for the small end. ive done it in the past before, but not on a 4 stroke, i dont see any reason why you couldnt do the same. give a bearing company a ring and see what they say, when i did it i just used a bearing from the shelf at work......
Can I point you in the direction of this thread: http://www.scootershack.co.uk/threads/peugeot-kisbee-4t-72cc-conversion-139qmb-e-information.30532/
Yeah , I stumbled app on that thread before xmas whilst googling the engine code , Good job I did as I would of been tapping away at the cam carrier wondering why it wouldn't come off, The small ends on these engines don't have a roller type bearing so limited to wrist pin size
