Hi, the stock setup is a 15 tooth 32 pitch gear. Thery're still available if you google around a bit.
You're prob wise to run milder motors with the 6 gear. The nylon idler gears in there are soft (esp after 20 odd years), and fail easily. I've gone through 3 gears in the last year running a 13double...
Amazingly, they're still available and CML still stock them. I ordered some from them through their shopatron website system the other week, and I had them in 24 hours. Amazing.
Here's a pic from the manual with the stock pinion.
Cheers!
Ty
