JL Exhausts sells an OW31 TZ350 reproduction top end. Does anyone know anything about this product or have experience with it?
Nope. They look like a 3G3 350G model cylinder with reed boxes. 350 cylinders and heads are slightly wider that 750 parts, so you can't use a TZ350 head on a 750 cylinder and vice versa. They have to be matched. I would suggest that they used the 350 design dimensions rather than 750 because there would potentially be a greater demand in Europe for that. As for port dimensions, I have no idea what they used, 3G3, TZ750D or something else.
Fondseca used to sell a similar part but again I have no data on ports or head dimensions.
Thanks for your reply Teazer! I was wondering if that OW31 top end would bolt on to an R5 bottom end? Joe