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My bike fell over at zero MPH. As luck would have it, the Pro Circuit Platinum II pipe (torque pipe) got a little dented by a rock that was in just the wrong/right place. I could keep the pipe on, but I decided this would be a good time to see what difference installing a new Rev pipe (an FMF Gnarly Desert), would make.

I'll pick it up tomorrow from MonkeyButtParts and install it tomorrow (Friday) night and maybe buzz around the neighborhood a bit. On Saturday I'll give it an actual test ride.

In the meantime, anyone care to guess what I'll gain and lose and by how much? I called ProCircuit and they said I'd lose "some" low-end torque. I spoke to another person who thought I might gain 1,000 to 1,500 RPMs.

Report to follow.

My Kingdom for a Dyno (just for fun).

Rick

well I did not loose or feel the loss of low end but boy!!! was I stuffing up the bike with the woods pipe. there is no end to top end 89miles per hour for a couple of seconds is fast, to fast to want more and low to mid is more bag for the buck. the pipe fit perfect, a little louder than the woods sounds like the KTM 300 I just sold and sure runs better. The desert pipe was the deciding factor along with the revalved suspension of keeping the KDX or KTM.

lesson learned: FRP says FMF woods is not for 220 ! he was dead right.

re aranging some shims helps but is miles away from a talented experanced suspension guru working with on and re valving the suspension.

89 miles per hour???

Rick, I've only had the Rev on my 200, but I love to ring that baby out. It will alter your riding style, becuse the burst of power up top. Of course this is with a 200, not a 220. Apples and Oranges in the area.

2001kdx wrote:89 miles per hour???

Ya!!! Iknow? this is the point at were I question the trail tech computer.

Somebody probably put an extra magnet on your rotor.

The rev is awesome, best mod I've done to it so far. You'll really like it in the sand washes down near the valley. I've had my bike topped out in some of the washes and could have used more top end. BIG difference over stock and I would assume a difference over your current pipe.

Rick, I suggest you do this. Come up to Flagstaff this weekend, ride some ST in the morning with the stock pipe and ride the cinders up here some (top out the bike no problem), install the Rev and ride the same stuff over again. You'll get a good testing of high speed and low speed stuff and compare the results. I remember you talking about liking a snappy motor, it didnt dissapoint me at all.

Seriously though, come up to Flagstaff some time, perfect temps in the 70s right now during midday, don't have to worry about being home by 10am because of the 110 het.

We were considering coming up to Flag a few times over the summer, but with my wife on a TT-R125, and my daughter on a CRF50, I have to choose my trails carefully.

The pipe is in my garage. I'll connect and test it after din-din.

Rick

You'll like the rev on the 220 . . . power increase: low end some, mid to upper gobs!!

I just ordered me one of those. I'll be looking forward to seeing the difference between it and my woods.

Jeb wrote:You'll like the rev on the 220 . . . power increase: low end some, mid to upper gobs!!

Keep in mind that I am not starting with a stock pipe. QuailChaser sold the KDX to me with a ProCircuit Platinum II (torque pipe) as well as carb and head squish mods and Boyesen reeds (I put VF3 reeds on recently). I have the stock pipe on a shelf in the garage but I've never had it on. So this is a comparison between an *after-market* torque pipe and an *after-market* rev pipe.

The test:
I already had my PC PlatII torque pipe off so I decided to go straight to the new FMF Gnarly Desert rev pipe. It bolted on with only a few cuss words and then off I went to warm up the motor for a few minutes on the street. Note -- I have usually found that my testing on the road doesn't communicate the same things as I find on the trail, so caveat emptor.

Once up to temperature I started going through the gears. First thing I noticed is that the FMF is louder than the PC. The ring-ting-ting is very pronounced, but the motor had a "smaller" sound to it, almost like I was on a 200. And as I took it through the RPMs and the gears, I kept hearing the constant (and loud) sound of an old-style phone bell. Ring-a-ling-a-ling. Ring-a-ling-a-ling.

The power off idle seemed a little smoother with the Gnarly. But my first thought was, "Is it smoother because there is less low-end torque?" As I took it to speed I found that I had, indeed, gained more revs on top -- about 1,500 RPM (to 11,000) according to the Trail Tech Vapor computer.

But this was only in the first four gears or so. When I wrung it out in 5th and 6th, I found that I was getting no more revs (a little over 9,000) and my top speed was 70mph. In the cooler winter months I had been getting 75mph with the ol' PC torque pipe. Of course, it was near 100F when I was riding tonite, so that robbed me of powah.

On the way home I did some 1st and 2nd gear wheelies to see if I the new pipe could get the front end light. It did fine, but my suspicion is that what it lacked in low-end torque it made up in throttle response. Some, but not all of my low-end burble was gone with the FMF. Perhaps a jetting, or A/S issue.

I pulled into the garage, got a snack and came back to remove the FMF and to put the ProCircuit Platinum II back on. I started the bike and off I went. No warm up was required this time. The KDX definately had more low-end power with the PC torque pipe back on. While it seemed that the FMF required me to wring it out through the gears, the PC had me short-shifting with more production of zoom and partial-throttle pull.

I took it out on the highway and found that my revs and top speed matched that of the FMF almost exactly.

So, on the street, anyway, the FMF rev pipe made my KDX feel a bit wimpy. It breathed better in the lower gears, but didn't have the cajonies to continue pulling in the upper gears any better than the ProCircuit torque pipe. The FMF produced less low-end torque, but that's not necessarily a bad thing depending on the riding conditions. But for me, riding tight and technical desert trails and rocky climbs, I can't see how the FMF would benefit me on balance.

So, if I were to make a rash decision right now with a gun pointed at my head, I'd put the FMF Gnarly Desert pipe for sale on eBay.

Anybody want a rev pipe with five street miles on it? $200, shipping negotiable.

Rick

Good review....

My 2hunny has a torque pipe on it right now... I have a REV but rather like the torque pipe and really see no reason to swap it out. There is nothing I ride in that would justify a REV profile pipe. I should try the comparison you tried but this would be FMF vs. FMF.

I had a PC pipe on my 92 and it was an excellent pipe too!

I think I'll put the stock pipe on just to see how bad it is -- or maybe I'll defy conventional wisdom and find it ain't so bad after all.

BTW, ProCircuit doesn't make a rev pipe for the KDX220 now (or anymore, or whatever).

Rick

Come on now, keeping that rev will teach you clutch control and make you better. You're not going to have the low end powa' on that KTM/TM/GG that the KDX has right now, and you've been talking about one of those for awhile.

If I can ride upper-moto with my revved out 220 at 7500ft then you can ride your FMF rev equipped 220 down in the valley. I even made it through test 3 no problem with it.

There are some good places to ride up here with family. Go to the cinder pits OHV near forest road 222 (past snowbowl, towards the Grand Canyon). There is a nice burm track and alittle MX track out there and is fairly friendly for kids. Then you can hop on your bike and do the Wing mtn loop which is about 1/4 mile ride away and that is one of the coolest trails on the mountain IMO. Come on up this summer!

BTW: Here's some pictures from that track taken a few days ago. (I like showing them off, I think they turned out kind of cool)
http://kdxrider.net/forums/modules/albu ... 1_copy.jpg
http://kdxrider.net/forums/modules/albu ... /jumps.jpg
http://kdxrider.net/forums/modules/albu ... p_copy.jpg

thebleakness wrote:Come on now, keeping that rev will teach you clutch control and make you better.

Yeah, but I'm yet to be convinced of any real advantage for the FMF. It revs better in gears 1,2, and 3 which means I won't be tempted to short-shift. But at the same time it doesn't have near the torque, and there is no top-end benefit for open-desert riding.

Where's the beef?

Rick

I think the confusion here is stemming from the fact that you went from a PCII to the FMF whereas I went from the Stock pipe to the FMF. I have never ridden (hell, even ridden with) a another KDX with a torque pipe. I really can't say much.

I would say there is a lot different variables, other than pipe swapping, such as RB head work carb work, FRP head work, porting and carb sizing also jetting, rider weight, and sure a few more I failed to mention. For my bike the
rev pipe is the best but I also have a 10oz flywheel weight ahh!!!! one of those things !! cant say anything bad cause I didn't loose any low end but gained mid and top also ended alot of jetting problems, but then with the Fredette porting this could be why he recommends the Rev/desert pipe and not the woods pipe. yet I know nothing of the PC pipe. hmm interesting read of info.

thebleakness wrote:I think the confusion here is stemming from the fact that you went from a PCII to the FMF

No confusion on my part. I'm used to folks confusing the baseline when this subject is discussed. That's why I made multiple mention of *after market* pipes and torque pipe vs. rev pipe and FMF Gnarly Desert vs PC Plat II, and other words to clarify what it was I was doing.

The bottom line is this: if a KDX220 owner with a stock pipe comes here and asks about an after market pipe, I don't think steering him to the rev pipe is necessarily the only direction to go. Not by a long shot.

If a 220er swaps his stock pipe for a rev pipe, he should know that while he will have improvements over the stock pipe (I'll test that later today as well) he would have significantly more bottom end if he went for a torque pipe. Also, those RPMs he gains won't be throughout the gear box, and won't mean higher top speed.

In my 2003 KDX220 with the head, carb, and reed mods, the rev pipe mutes the bottom half of the RPM range while not doing anything particularly earth shaking or useful in the upper RPM range. Your 220 might be different, but I kinda doubt it, and nobody here has done the research to prove otherwise (or at least they haven't bothered to post during the last seven times this subject has come up).

I've proven to myself that this Fredette-based conventional wisdom on the rev pipe for the 220 is not all it's cracked up to be and might not be worth the trade-off in low-end torque that a fleeting hint of upper revs brings.

This dogma has died.

Rick

A 220 in stock form will climb a tree... how much more bottom end is needed?

That's Interesting how you perfer the PCII rick. I need to buy a woods pipe for my bike, but RB carb and Head mods come before that. You're right, the Rev does not benefit anything close to "tight" woods riding. All I know is, it packs a punch. When I get into an open field, I rev 3rd out completely and when I hit 4th gear it wheelies enough to where I need to let off throttle to keep my 225lb butt on the bike. It's just fun to have a pipe that really responds to being "on it", wide open.

Indawoods wrote:A 220 in stock form will climb a tree... how much more bottom end is needed?

I think the folks who do the carb, head, and reed mods will have to answer that. Them, and the ones who opt for the KTM 300, or the 450 four-strokes.

The point of this thread is not how much is needed, but whether one solution is better than the other.

And 2001KDX, remember, yours is a 200cc, bike, not the 220. Different animal, and I look forward to your rev vs torque thread when you get your new pipe.

Rick