I got tired of waiting for money for parts so I pulled the bikes in the shop to start working on whatever I could do without parts.
First thing I did was swap the forks. Both bikes have 43mm forks, so the job was very straight forward. According to previous comments in this thread, the '98 350 had cartridge forks while the '91 250 didn't. But the '91 250 has adjustable compression, so I'm guessing it too has cartridge forks.
- The 98 350 has a larger axle
- The 91 250S has adjustable compression and preload while the 98 350 has adjustable compression and rebound.
- The 91 250S has a longer brake line so it can get around the gauge cluster (this might be helpful to someone installing taller forks on their bike).
- The 250S has fine thread on the caliper banjo bolt while the 350 has course threads.
- The 250S upper triple clamps have extra brackets for the gauges.