Power Valve

[Woody_393]

Just a general question that I'm hoping someone knows the answer to.

What year did they first put power valves on 2 strokes, or have they always had them?

[cr-manp4l]

i think the correct answer would be 84 or so they havent always have them they used to have strait exhaust but i am guessing 84 or so

[Aus_Rider_22]

I guess you mean the first bike ever to have powervalves, as some bikes (CR80, YZ80) only got them in 2003 i think.

So it depends on what bike size and manufacturer.

[Woody_393]

Ok then make it both 125 and 250

[FFRacing11x]

In '82 Yamaha came out with their YPVS system, and in '84 Honda came out with their version called the ATAC.
[Only registered and activated users can see links. ]

[Woody_393]

Thanks FFR

[mtk]

Originally posted by aus_rider_22
I guess you mean the first bike ever to have powervalves, as some bikes (CR80, YZ80) only got them in 2003 i think.

The CR85 still doesn't have one to this day.

[Woody_YZF]

My '83 YZ 250 had a power valve, I'm pretty sure.

[Woody_393]

Originally posted by Woody_YFZ
My '83 YZ 250 had a power valve, I'm pretty sure.

According to FFR's info from Eric Gorr it certainly did. however it looks like the 125's didn't get them until later.

[Roostman]

The "power valve" that the Yamis used on thier 82s wasnt a conventional unit as you know it now, but rather a box type unit that was mounted off to the side under the tank and connected to the motor with hoses. Im really not sure "how" it worked, but my '82 YZ 80j (bought new) ran great.

[HondaOnly]

This is a little off topic even though in regards to 2 stroke powervalves. Anyone know what the "RC" in hondas RC valve stands for?

[kxdude258]

98' was the first year that the kx80 had a power valve

[FFRacing11x]

Originally posted by Roostman
The "power valve" that the Yamis used on thier 82s wasnt a conventional unit as you know it now, but rather a box type unit that was mounted off to the side under the tank and connected to the motor with hoses. Im really not sure "how" it worked, but my '82 YZ 80j (bought new) ran great.

Roostman, the part you are talking about was called a "boost bottle" and it was connected to the intake, not the exhaust. The YZ's in fact had the YPVS in '82 in addition to the boost bottle for the intake. Tdub

[Aus_Rider_22]

It's funny, that Honda CR80's don't have the powervalves yet, as they pretty much have the space and parts already on the bike.

I remember looking at a 02 CR80 and the mechanic said that is pretty much has the PV mounting set-up except for the arms and another part.
But basically there was space where the powervalves should go.

But I guess Honda want to keep the CR80 a top-end screamer.
And, that leaves them able to reveal the powervalve at a later date.

[FFRacing11x]

The CR80, as you said, has had all the bosses and such casted in the cases for years. Wonder why they never decided to go that route? Maybe cause it is the fastest 85 out there without it? tdub

[Aus_Rider_22]

Yeah, I guess Honda thought they would gear there 80 as a top-end screamer and therefore appeal to more experienced riders.
But really, it's a good move as that's where you want an 80 to be, high in the rev range.

[TRXman86]

what does a power valve do any way? call me dumb but i dont know LOL

[yz_zinger]

Originally posted by HondaOnly
This is a little off topic even though in regards to 2 stroke powervalves. Anyone know what the "RC" in hondas RC valve stands for?

i would have to say "RC" stands for Ricky Carmichael

[yz_zinger]

Originally posted by HondaOnly
This is a little off topic even though in regards to 2 stroke powervalves. Anyone know what the "RC" in hondas RC valve stands for?

i would have to say "RC" stands for Ricky Carmichael

[HondaOnly]

Originally posted by yz_zinger
i would have to say "RC" stands for Ricky Carmichael

Yes, I was joking about that with my friends. We will just have to see what its called next year, wont we? Lets just hope that this isnt the case. If it is, and some day Bubba stewart becomes Honda's star 250 rider, we may have ourselves a BS valve. Most likely the RC valve has some other meaning, just not sure what.