Gearbox time.
Got hold of a jzx100 r154 which was stuck in fourth gear, pulled it down to find a stretched and broken fourth gear synchro ring and hub.
Next....got hold of what was a brand new jzx100 box with a stripped third gear, which was used in a mates car for one drift round before he converted to a sequential dog box.
Add a pair of Marlin Crawler billet shift forks, a full face thrust washer and a billet centre plate and I should be able to make something work...for a time...