Just done my DRZ for the same fault, all new bearing and oil pump, cam chain and guides as well all for about R 10000.00
the symptoms I had was, could not select gears ,
when we opened the clutch cover and removed the clutch we found the bearing basket on the main gearbox bearings had collapsed, the main bearings were also blue from overheating,
we got all the bearings bar the two main crank bearings from bearing distributors on Vredenburgh and the rest came from Suzuki , bearings from bearing supplier R 560, 00, two main bearings from Suzuki R 585.00 each was an expensive undertaking but now the bike runs sweet,
I got the bike on 8000 km, I have done 15000 on it, I have serviced every 3000 with Castrol actovo and new filter. I don’t know what the motor was run on before but there was some evidence of bad maintenance and some bolts loosening with a chisel from the previous owner,
The mechanic that put it all together for me was a stickler for doing things correctly, everything was properly washed including the oil tank with 25 flushes of diesel before we got all the metal out of the tank, so If you are going to rebuild let me know I have a great mechanic friend who now knows the DRZ motor intermit.