The B1/B2 T3 (86/87) and the T4 engines were completely different. The stroke x bore was flipped and the port timing changed up. The T4 engine is the 'blaster' of the 250's. But once you've modded it it does come to life.

Harry Klemm was THE Tecate guy, now Sprock is the guy. Both Klemm Vintage and Sprock Racing are still on business and Klemm is doing R&D on building the 350cc Tri-Z engines again.

Oh!! And there was another company that was big with the Tecate back in the day that is offering their 310, 330, 350 and 375 (I think a 375,,, can't remember..) engine kit again