JL 1 Based on KRP 1 (Kegra) 4 piece unit for touring performance
JL 2 Based on KRP2 (Kegra) this is a 3 piece unit for touring/fast road
The JL2 is a lot narrower around the fattest part of the expansion chamber (roughly 92mm)then the JL3
JL 3 This was Taffspeed design this is a 3 piece unit for fast road/ Race giving good all round performance
The JL3 is distinguished by it being bulkier all around, but very similar and uses the same manifold and endcan support as JL2, around the fattest part of the expansion chamber (roughly 110mm)
JL 4 This was Taffspeed design this is a 3 piece unit for Race
This can be distinguished by its swan neck manifold and short tubby chamber with long stinger.
JL4 Race system is one of the best exhaust system that you can fit to any TS1 engine giving serious power & performance.
Smiffy