- Mar 15, 2009
Yeah, I got the stroke and bore numbers mixed up. I went back and edited it to correct, but apparently not quick enough.Re; “Maybe we are talking about two different bikes?
frequently referred to as TZ700s, but they were officially cataloged by Yamaha as TZ750 right from the start.
They expanded it to 748 cc in 1974 by increasing the stroke.
All of them had reed valves.”
The TZ range in the 1970s more or less until they changed them, all had 54mm stroke at one time, the 700 were made from the 500 GP racer at the time but fitted with 38mm carbs -later reduced for the reed block 750s to make them more rider friendly. There was a lot of mix and match of parts barrels, I have had a 350LC with a 350 TZ barrels on, seen a TZ350 with TZ 750 barrels on, (for someone who wanted to race at clubman level in the 500 class.
But I still think I'm correct about them, including the 700s, all having reed valves, at least when they left the factory. Every reference I've seen, including the Carole Nash one above, agrees on that.
As you said, lots of possibilities for barrel swaps between the 350s and 750s. I have a friend who races an RZ350 here in AHRMA vintage races, and he says you can now buy aftermarket cylinders and crankshafts to take them out to over 500 cc. That should make a real monster of a street bike.