Frame worn out at the lower part of the steering stem (bearing race) on PW50

[RadekSkylark]

Hello everyone!

The season is starting and yesterday I tried to replace the steering stem bearings on my daughter's PW50. Unfortunately, I noticed that the bottom bearing race is not fitting tightly in the frame because the frame seems to be worn out on the inside. Because of this, the bearing race wobbles around by 0,5-1,0 mm (0,02"-0,04") side to side, and thus when re-assembled the lower bearing is non-functional as it turns together with the steering stem.

I'm using an aftermarket bearing kit, so I'm not 100% that everything is correct, although the upper race, nut, as well as the race that presses onto the steering stem, is the same dimensions as the original that was already on the bike (not sure about the lower race that goes into the frame, as this had split at the end of the previous season so we dumped it).

As I understand, the diameter of the part of the lower and upper race that goes into the frame is the same (that is, the inside diameter on the top and bottom of the frame where the races need to sit is the same), correct? If so, then indeed the frame has worn out a lot... I'm not sure how that could've happened.

Anyways, has anyone ever experienced such a problem? If so, what was the remedy?

Thanks

 

[jannick]

It sounds like the frame of your daughter's PW50 has worn out on the inside, where the lower-bearing race is supposed to fit. This is a relatively common problem with PW50s, as the frames are made of aluminum and are not very strong. You can try to find a new frame for the PW50, and you can visit Steering bearings for motorcycle designations and dimensions enquiry list - en.tradebearings.com if you need new steering bearings. This is the best option, as it will ensure that the frame is in good condition and will not wear out again. However, new frames for PW50s can be difficult to find and can be expensive.

 

[dirtbkr188]

I'm 99.99% sure the PW50 frame is made of steel, not aluminum

 

[jannick]

I'm 99.99% sure the PW50 frame is made of steel, not aluminum

ok, maybe i made a mistake, i'll check this