New Bike

yzeater

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#1
ok. so i finally moved up from an xr100 to a cr 125. i have no idea how to ride this thing. the brakes actually work and it has more than 8 horsepower...soo, can you give me general suggestions? Thanks.
P.S. What is this i hear about a powerband?
 

CRGuy

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#3
The powerband is when the engine pick's up in power quickly and is right around the center of the RPM's. It's made by a small chamber that open's to increase cylinder volume.
CRG
 

Danman

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#4
You can get those powerbands in any color that you want at the honda shop :p Just kidding. :) I think you should listen to CRguys post unless you realy just want to go the nearest shop and ask for a red power band to match your plastic:p
 

CRGuy

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#5
Ewww a red one! I told my mommy to only pick up the black one's!:p
J/k Look at my first post. LOL
CRG
 

High Lord Gomer

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#6
Originally posted by CRGuy
The powerband is when the engine pick's up in power quickly and is right around the center of the RPM's. It's made by a small chamber that open's to increase cylinder volume.
CRG
PLEASE do not attempt to answer questions as an expert if you do not really know the answer!

If you plot horsepower and RPM on a graph, the "powerband" is the range of RPMs during which optimum power is made. It is used to describe a range of RPMs. It is not a physical object that can be touched.

On most 125s, it is fairly high in the RPM range.

The powervalve opening to effectively raise the exhaust port does not "make" a powerband. For a better understanding of all of this, I would suggest searching on: Powervalve, PV, and powerband in both the advanced tech and Engine Modification forums.
 

CRGuy

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#9
So what is that chamber for then? I know it has something to do with the powervalve. I didn't mean to make it seem like it was a physical object only the chamber is physical.
CRG :eek:
 
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#10
The powervalves give 2 strokes more low-end power. It is basically a piece of metal that starts off covering part of the exhaust port to give you more low end, when the RPM's go up so do the powervalves until finally they are up all the way recessed inside of the cylinder.
 
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CRGuy

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#11
I just looked at my manual. I see the valve's and how the operate.
Ok now that's strait. Why would you put a thicker gasket for the RC vlave cover? It wouldn't do anything.
CRG
 
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#12
I am not familiar (yet)with the Honda exhaust valves, but in general there are a couple of parts to the valve system.
One attempts to alter the effective compression by altering the exhaust port timing. These valves being closed results in a higher effective compression ratio and exhaust velocities (better bottom end power).
The other part attempts to effect the returning exhaust compression wave by opening what I think Eric refers to as a surge chamber (at least for the Kawi Kips system). I think that changing the volume of this chamber is what we are refering to with the larger PV covers.

I am probably not describing this correctly though.
 

High Lord Gomer

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#13
What do you mean by the "RC valve cover"?

If you mean the Reed Cage, a thicker gasket (or a spacer) would effectively enlarge the intact tract, but that's a whole different animal than the powervalve.

We better stop this in here before Wardy makes us move to Rich's or Eric's room. :scream:
 

CRGuy

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#14
Not the reed cage:silly: Honda call's there power valve's RC valve's. I don't know why.
Yea I think we should stop before we get moved. ;)
CRG
 
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#15
I just got my Red Rider magazine. Know I understand what he means by RC valves.

In the mag, they talk about the servo controlled power vavles. They refer to them as "RC style". I think they mean that they are the same as some of there sport race bikes, aren't Honda's racing 2 strokes models "RC" ?