If you’re thinking about replacing your steering bearings on a pre-79 GS550 and 750 the pyramid parts BR21 kit probably won’t work right out of the box. I choose it since all balls stem mod was beyond my capabilities, and it seemed like pyramids kit didn’t require any mods. I was mistaken and have asked them to update their BR21 kit to prevent this from happening again.
The problem I ran into is a shoulder on the lower steering stem shaft causes the upper bearing to bottom out prematurely. I was left with ~1mm of play. You can solve it with a 1.5mm shim below the lower bearing. There is a shim from Suzuki (09181-30184) off a later gs550 that should work. Pyramid ended up sending me a new seal lower bearing and shims, since I wasn’t too confident about nondestructive removal. The all-balls stem mod also works but the setup and tooling is rather cost prohibitive endeavour.
Bearings were NTN 254815 on top and 274814 on the bottom for reference.
The shoulder I had issues with measured ~173mm to the steering stem.
I'd imagine pyramid will send a shim the first time around if you include a note. Hopefully they'll update the kit.
The problem I ran into is a shoulder on the lower steering stem shaft causes the upper bearing to bottom out prematurely. I was left with ~1mm of play. You can solve it with a 1.5mm shim below the lower bearing. There is a shim from Suzuki (09181-30184) off a later gs550 that should work. Pyramid ended up sending me a new seal lower bearing and shims, since I wasn’t too confident about nondestructive removal. The all-balls stem mod also works but the setup and tooling is rather cost prohibitive endeavour.
Bearings were NTN 254815 on top and 274814 on the bottom for reference.
The shoulder I had issues with measured ~173mm to the steering stem.
I'd imagine pyramid will send a shim the first time around if you include a note. Hopefully they'll update the kit.