Ok, so while I've got the FrankenYager apart, I decided to splurge on hybrid ceramic silicon nitride ball bearings. They'll be micro-polished and coated with tungsten sulfide to make them rotate even more easily than ceramic bearings already do. The new rear gears that Jan Vos cut for me will also be micro-polished and coated, thus no gear break-in and less friction. This is from a company named MicroBlue.
I'll be doing this for all the bearings on the bike eventually... when I drop the new head on, I'll tear the engine down, do a full inspection, and drop in the new bearings there. For now, the new bearings will go into the wheels , clutch and rear gears.
Anyway, the bike has 12 bearings total, two of which are drawn cup needle bearings. They're the typical cheapy needle bearings that come on most GY6-based scooters, with a nylon roller cage... and the one on the clutch is worn out. Since there are no hybrid ceramic needle bearings, I'm stuck using conventional ones, but I want to go with ones that at least have a metal roller cage so they last longer.
Here's the measurements of them:
14mm bore, 20mm diameter, 12mm width
20mm bore, 29mm diameter, 18mm width
Anyone know of better drawn cup needle bearings than the cheap Chinese ones? I've tried SKS, FAG, INA, Timken... seems only the Chinese factories churn these out... strange, given that everyone riding a GY6-engined scooter has these bearings, and a higher quality replacement would likely be a big seller.
