GTL gearboxes have the tapered end with keyway, and new sprockets for them are as hard to find as new crank bearings.
Until I have found a commercially viable method for alternatives for GTL sprockets, I have diverted efforts into the SD/GTV gearboxes as these have the “regular” 6 spline shaft like the pantah. Again, ploughing through the JT Sprockets catalogue an alternative was found, although it was a 520 chain rather than original 530. The thinner chain is not so much an issue as modern 520 chains are extremely strong, but it does mean sprockets for the GTL have to be modified. SD/GTV wheels have the same sprocket carrier as the pantah/750Paso/Sport 16″ wheels, and those sprockets are still readily available.
the front sprocket was found to be the same as a Yamaha 250 dirtbike, and available in Z12 and Z13, just like the 350 and 500 models. A distance bushing is required to ensure correct chain alignment.
front sprocket 520 (SD/GTV): JTF431.12 (350) and JTF431.13 (500).
rear sprocket 520: JTR491.38 and JTR491.40
rear sprocket 530: JTR1022.38/40/41/47
fitment 520 front sprocket: place the collar to the outside so front sprocket backside is flush with rear sprocket backside.
spacer required for 520 sprocket: 22(+0.2/-0) x 28(±0.2) x 6.7(±0.3) mm
advised: strong belleville spring washer DIN2093 22.4 x 45 x 1.25 with loctite 242/243.
We are currently in negotiations to get GTL sprockets manufactured in 530 chainsize
(5/8″ x 3/8″) for both 350 and 500 models, z=12 and z=13 respectively.