what does yamaha ypvs (yamaha power valve system) mean?

Answer 1

The ypvs is a valve which opens as the revs rise, its servo assited valve opperated by cables usally found on the left hand side of the barrel. At lower revs the engine will run better with a smaller exit hole & at higher revs the engine will produce more power with a larger exit hole. If u run a a RD or TZR 250/350/500 it is best to check they r set up correctly & while ur at it balence the carbs.

Answer 2

Yamaha Power Valve System

Answer 3

Itis a system that alters the exhaust port timing as the the throttle is openened cos apparently some w****** did not like the on/ off power characteristic of the non power valve model but personaly I think it ruined the bike.At that time there was 4 of us who had hyper tuned ellsies we spent nearly all of our wages on the bikes at that time Stan Stevens m/c,s was the god of all ellsie tuning even forked out on a speciality of his which involved a restroke and rebore out to about 420cc or there abouts and on top of that a formula 2 tune + having the crank permantly welded at 180 degrees cos ellsies could and did annoyingly spit out crank pins when being abused so having the pins welded in stopped the problem add to that a set of ultra illegal expansionpipes from Swarbrick engineering and you had a pretty good ellsie not forgetting a pair of power jet carb and of course on the induction side carbon reeds leave the air box in place but take out the filter element so it gives the carbs a nice still air resevoir which they do need to let them breathe if not the air tends to be going past too fast for the carbs too grab next on the agenda is the handling which with a standard motor is iffy when pushed hard so it then got tricky we had to find a better frame and brakes ,forks,swing, arm other than spend approx £1500 on a Spondon race fame just find a Suzuki Gamma frame and put tuned ellsi motor into it then you had a hybrid called a YamaGamma cos the Gamma had upside down forks and stuff and better bodywork hope that gives you some ideas all sadly a bit old hat now but we had fun and loads of crashes let the blue smoke roll into clouds first thing in the morning got a set of standard ellsi barrells in me garage plus another complete bike with a broken crank @ 13,500rpm on the way home from work in about 1989 sorry got off the subject a bit but it brings back so many smokey memories might get the crank done on the purple retro crotch rocket and get the thing welded this time I didnt last time thats why it broke !and locked the back wheel but being a lucky sod managed to stay on the thing

Answer 4

-Let me add to MICHEAL R's answer. It's a valve in the exhaust port. It's the width of the port and flat. The valve lowers and rises from the top of the port (imagine a garage door opening and closing).
-Let me side track for a second. When the piston is on it's down stroke after firing the fuel mixture. The exhaust flows out of the exhaust port, just as the piston moves past the port. If you were to grind away a milimeter or two from the top of the exhaust port opening, you'd be changing the port timing. The exhaust would escape sooner.
-The power valve is doing the same thing. When the valve rises, the opening of the exhaust port is higher. The valve is constantly changing the port timing for maximum power at different rpm ranges.

Answer 5

Yamaha ypvs means yamaha power valve system.

Answer 6

PARADOX....God... someone who rode H1s and H2s and has lived to tell the tale. There's two of us still alive then. Still got all your arms and legs as well??

I can remember the YPVS valve rotating as you turned the ignition on to clear any carbon from it. RD250LC and RD350LC.

Answer 7

fantastically no longer likely. you could discover yet another Cagiva form head- SP2, 3 and a 525 form have been comparable engine with some distinct wheels and styling, distinct years. you're concerning the pinnacle and not the piston?

Answer 8

simply means widow maker very fast

Answer 9

how many or how big