Following on from the overview video, this is an in depth description to the YPVS system on the Yamaha RD 500 (also called RZ500 in Canada and Australia). I also give a quick look at the YZR replica that I'm working on ...!
Thanks for an excellent video - it’s a good idea to Loctite the power valve cap screws - they have a tendency to work loose over time - the temptation is then to over tighten the screw which can crack the tab off - don’t ask how I know 🙈
A 350YPVS and a couple of TZR's owner, I think it was the most elegant system, all the other's copied it to lesser degrees trying to avoid the patent, and yes those valves got gummed up with all sorts of gunk. Really noticable when a seal would start going on that outer cover.
The TZR (1KT) his pretty much identical to the RD500 - the barrels and heads are pretty much the same - so it was effectively half of an RD500 (but with a better frame!)
I had two 500's... and a 350 when I was young. Loved it. Kinda slow standard really, here in Australia, but I just tidied up the ports. I guess you'd call it a shade above blue printing. That and a few other things. After that it was pretty quick, SUPER fun to ride.
I want that motor! My first 3MA used to wear down that flat on the power valve, and my dad, a precision toolmaker, welded it the first time, the second time it happened, he made new ones with a different aluminium alloy and coated them with the same stuff he would vapour coat onto cutting tools and been over 20 years, and it never happened again.
Hi Brandon, yes it does have two shafts - I have done another video which gives a full overview of the engine which you might find interesting. A also have an FZR1000 Exup but the exup valve has seized solid - a very common problem! They need to be used!!!
the only real mod is to just make the exhaust ports bigger, but that can't really be done in isolation - all the ports would need to be worked on together.
