Peugeot Kisbee 50cc woes.

[WmY]

Well, there doesn't seem to be an "Introduce yourself" subforum; please correct me if I'm wrong and I'll write something there.

So my son, 16, wanted a moped/scooter (licence class AM). So, we thought, oh, no, no, not one of those Chinese things... it would be better to get a European one. HOLLOW LAUGH. The Peugeot Kisbee bought second-hand, if it isn't actually made in China, has a Chinese 139QMB-E engine. Bother.

So, at 9,500-odd Km, about 400Km after buying it, it started to rattle....

Stripping the thing shows that the alternator-side main bearing's bearing cage has collapsed. The big end seems OK. So, replacement main bearings are needed.

The drive side bearing is a standard & popular 6304 deep groove ball bearing, unshielded, standard clearance.

The alternator side bearing is similar, but a funny one - it's got "SC03A39CS" stamped on the outer race, and measures 17-42-13 (mm).

Any ideas on where to get good quality replacement bearings, please?

[Octapode]

This would seem to match your specs: https://www.123bearing.co.uk/bearing-SC03A39CS20-NTN.php

This kit looks like it matches your engine: https://www.pedparts.co.uk/product/3192/bearing-and-seal-kit--chinese-gy6-50cc-4t

Both look like they're the same NTN bearing, so either should be decent quality.

Hope that helps.

[WmY]

[WmY]

OK, for completeness:

Pedparts say new stock will take 2/3 weeks to arrive. Their kit ( Bearing & Seal Kit - Chinese GY6 50cc 4T #P3192 £24.95 ) is a good price including both bearings and seals.

In view of this I ordered from 123bearing. The cost is rather higher though (about £32 without seals BUT including VAT and 2day delivery (from France) ).

Notes:

Bearing (alternator side):

The Pedparts 6204 bearing has C4 clearance[1]. This is "slightly loose" apparently to cater for big bore conversion kits.

123bearing recommended a C3 bearing for this application (above 70 degrees C, high speed). This clearance is not so "loose" as C4. I ordered this one.


Bearing (drive side):

123bearing was again extremely helpful. They carry two equivalent bearings: SC03A39CS20 and 6302-17P53, both made by NTN. I include these numbers since they are not easy to find "from scratch".

[1] For more information on bearing clearances see: https://www.skf.com/uk/products/bearings-units-housings/ball-bearings/deep-groove-ball-bearings/designation-system/index.html?WT.oss=c2%20c3%20c4&WT.z_oss_boost=0&tabname=All&WT.z_oss_rank=1 and elsewhere.

[WmY]

My goodness! The detritus in the engine; flakes of metal from the chatter on the inner race, alternator side, plus knock-ons; wash them out with paraffin, blow through the galleries and surfaces, even the gear-type oil pump is full of it. Still, after a spell cluttering up the workshop, it'll be cleaner than it was at manufacturing time. Haven't seen such stuff in an intact engine since the old Matchless developed octagonal roller bearings in the big end.

[Gcardale]

Hi, I am rather afraid my sons has had the same issue, there is a loud knocking side from the left-hand side of the engine block. How difficult or straightforward is to split the engine , and will the engine need to be fully split to fit the bearing ?
____________________
George

[MCN]