I have the HPD pipe and clutch kit on my 2000 Scrambler 500 4X4. I ran it for a week with just the pipe, and there was really a difference. The clutch kit helped, but I think the pipe really made the most difference. Make sure you get the K&N air filter and a bigger main jet with the kit. Take your time and also make sure you keep the pipe routed away from the plastic. When we set mine up, we did it so the drain hole on the muffler was on the bottom, so that moisture could drip out. BAD IDEA!!!! This put the pipe too close to the very expensive and sensitive plastic. My advice to you is don't worry about the drain hole. Having the pipe routed away from the plastic is WAY more important than getting the drain hole exactly on the bottom. Oh yeah, as far as the sound goes, it sounds awesome. At idle, there really isn't much difference in how loud the two are. Although the HPD thumps a bit more, which is cool. As you get on the gas, you will notice the HPD pipe is louder, but it is by no means obnoxiously loud. It is an awesome improvement!!!! Do yourself a favor and order it today!

 

Very interesting dyno chart.

Every complete dyno run sheet that I have ever seen shows a power curve drop off.

Now please forgive my next question.

Could this be an artist's conception of perceived power?

 

Well I got the Clutch kit on everthing went according to plan..lol
There is a pretty good improvement from what I tried the front wheels pop up easy now better than before I almost went right over backwards
there is also so mid range now that before was none exsistant pulls pretty hard when punching the throttle from 1/4 or 1/2 to WFO.........
Now the engine does not rev as high as before top end feels slower but I think it is just because the engine is not reving as high I have not timed it but it feels quicker to get to top speed...
All in all I am pleased with the out come I am gonna drop a jet size though because it is starting to warm up stock was a 155 I put in a 165 when I installed my K&N filter but I think I will drop down to a 160 and then I am gonna get my pipe as soon as possible.......
I am not to sure what HPD's carb and airbox mod is.......Anyone know ????
After the Pipe I will getting the cam and buy the time this ia all done the 700 Scrambler should be out and I will trade my bike in .......lol.
I will keep ya all up to date on my progress

Have a good one

 

Thor
the dyno was in the back of the HPD catalog I got with my clutch kit.
You are right though they usally show where the power drops off. I am not sure if it for real or not but if it is I will be happy when my mods are done. And if not I will be a little poorer but none the worse for wear because I like to tinker on the Quad anyway another hobbie if mine.

Have a good one

 

Oh, okay thank you for the response. I am also looking for a little bit more out of the clutch on my machine. I would really like 2 things

A quicker back shift

More rpm to overcome "overgearing" but since there is an ebs secondary I am left with weight and spring changes in the primary unit.

I don't really want a higher engagement point. So it looks like the white and or green spring are out. So...

Perhaps I could swap in the 48 shift weights and the white spring and see how it goes

 

lancems007,

Was the HPD clutch kit worth buying? or would you just recommend the pipe? And how are is it to install the pipe. I've heard you have to remove some factory mounts to install their pipe, that it doesn't mount to the factory pipe mounts. And if so, does their mounting system not rattle?
That's the pipe I want, just not sure about cutting stuff off my quad. Let me know what you think of it.

 

My HPD pipe is on the way I should have it by friday of next week I think or sometime next week I will let you all know how it goes once I put it on.

Have a good one

 

".....Now the engine does not rev as high as before top end feels slower but I think it is just because the engine is not reving as high I have not timed it but it feels quicker to get to top speed...

+ You need a tachometer to determine where the engine rpm range is. The shop manual for the 500 engine indicates that peak power is made at 6500 rpm. A 200 rpm over-rev is allowable for maximum performance. When you open the throttle the rpms should jump to 6500 and stay there all through the acceleration phase and into the top end speed run.

+Lighter weights in the drive clutch increase rpm speed and heavier weights decrease rpm levels.

+ The drive clutch spring also determines to some degree how fast the belt will move up the sheaves and into a higher "gear"

+ The second part of this equation is the secondary clutch which has 3 holes on one pulley and 3 holes on the helix. The placement of the spring in the corresonding holes will determine upshift rate, backshift and total rpm. 2-2, 2-1,2-3 etc. etc.

+ It all depends upon where you want the power to come in. It is like a piano keyboard. Only so much sound is going to come out of the piano, but you can determine if the notes (power) will be low, midrange, or high.

Under-reving or over-reving will rob power. Your engine needs to be operating at 6500 rpm throughout the powerband that you want to play in.

Unfortuneatly there is no free lunch. If you want massive wheelies and brute fore acceleration, you may have to give up some low speed driveability and top end speed.

"All in all I am pleased with the out come I am gonna drop a jet size though because it is starting to warm up stock was a 155 I put in a 165
when I installed my K&N filter but I think I will drop down to a 160 and then I am gonna get my pipe as soon as possible......"

+Many of the 500s have performed very well with the 160 jet. (Especially with the warmer weather coming on.)

"I am not to sure what HPD's carb and airbox mod is.......Anyone know"

+ Be careful, the Scramblers and Sportsman operate with a designed air box pressure in mind for the CV carb to operate at peak efficiency.

+ I would start with the tachometer and observe the operating rpm rev range. Good luck

 

Thanx for some of the info there Thor.
I have been debating getting the HPD tach for the ATV maybe I will now.
I am not too sure now about the engine it may rev as high it might of been just me being PARANOID!!!!
I should be recieving my HPD pipe soon I think that is gonna bring everything together nicely.
When I got my clutch kit it was the one HPD sells for a stock engine Scrambler and is supposed to be good for a pipe it has the HPD plain primary spring 55 engage and shift out at 215 and a Violet secondary spring and the helix was a 44/38 I think and the wieghts were I think 48 or 49 grams and the secondary spring was in the first hole on the helix and 3rd in the clutch so what do you think ??????
Anyways i will let you know how the pipe goes

Have a good one

 

When I got my clutch kit it was the one HPD sells for a stock engine Scrambler and is supposed to be good for a pipe it has the HPD plain primary spring 55 engage and shift out at 215

+That would give you an engagement rpm roughly equivalent to the Polaris "green" spring and higher than the white or standard blue/green spring with a full shift out at 215 which is stronger than (9) of the Polaris factory springs.
In order to compensate for this higher spring tension HPD has supplied heavier weights to balance the equation.

"...and a Violet secondary spring and the helix was a 44/38 I think and the wieghts were I think 48 or 49 grams and the secondary spring was in the first hole on the helix and 3rd in the clutch so what do you think ??????

If you are in hole #1 on the helix and #3 on the sheave you are in the position for the fastest upshift and slowest downshift. This combination produces the least amount of drive belt tension in the driven clutch. The Polaris Shop Manuals are invaluable for this information.

Perhaps the addition of a pipe will bring it all together for you. Bonne Chance.