I changed my 220 from the Rev pipe to the Woods pipe and I’m very glad I did

[Tokyotim]

Bike is much less yz250x and more KTM300EXC which is what I was going for. It goes very slow in first gear now, which it did not like to lug with the rev pipe. I will change to 13/50 gearing and I do have a Steahly 10oz flywheel but I do not think I will need it. I am still dialing in the jetting but it is much less aggressive power now which I like being a slow hard enduro rider. Next year hope to enter it in some enduro events even though kick start will be annoying

[Chuck78]

I've been telling people to disregard certain well known KDX/KX retired racer well known engine builder and KYB suspension guru advice as well as similar advice from others for a long time, and to still include the Gnarly Woods torque pipe as a viable option for the 220 for those who want smooth power delivery and even better torque.

Taking a cylinder that is ported for mid-range torque and lugability below the power band, and putting a mismatched pipe on it that alters it's performance drastically, is not the way to extract maximum efficiency and power by putting mismatched components together to achieve a middle ground compromise. If, however, you end up owning a KDX 220 when the KDX 200 Power band really suited you better for wide open terrain and nothing technical, then the Gnarly Desert pipe will come closer to achieving that result of making it more 200-like.

While the 220 is not as fast of a bike overall with the Gnarly Woods torque pipe, the smooth tractable powerband and SIGNIFICANT stall resistance is absolutely wonderful. It doesn't necessarily move the low RPM power delivery significantly lower as it does giving it such a smooth tractable torque while enhancing the lower RPM performance. The porting dictates where the power starts building at, more so than the pipe, the pipe just enhances it in certain ranges while cutting a few horsepower off of the entire curve at the upper RPM ranges and dropping the peak RPM several hundred rpm lower. With the stock CDI ignition curve, even adding the gnarly desert pipe to a KDX 200H does not really extend the high RPM power or higher, although it will rev higher, there is not much benefit to revving higher unless you are running a custom ignition box that has more high RPM timing retard to make use of that higher rev out capability. Then you can actually begin to maximize the Desert pipe and actually gain power in the added RPM range of the Desert pipe. The pipe just enhances the power in the range that the porting is catered to if using the stock CDI, with an emphasis on enhancing the power in the upper ranges versus enhancing the power in the lower ranges.



I will be running a KDX 220 SR head (very wide squish band with tight squish clearance, emphasis on torque like the Gnarly Woods pipe) modified for a 70 mm KDX 220 overbored cylinder with some porting work, and the Gnarly Woods pipe, on one of my three KDX engines, installed in a '99 KDX200 chassis. It will be the lower ride height bike that is stock or maybe slightly lowered, and lightened up slightly, for technical riding and a loaner bike that will do well with beginner pilots .

The '97 KX125/KDX220 hybrid and my '97 KDX220R both will be running the Pro Circuit Platinum 2 pipe, which is definitely my favorite overall as it has some of the Gnarly Desert like characteristics without wasting any tune on extending the rev range without making more power, while it gives more low end and mid-range torque than the Gnarly Desert pipe by a very worthwhile amount. Since it is focused on mid-range power and more power everywhere overall, it does come with a price, and that cost is a trade off with a pretty significant power band hit for a wood bike... It's something you can learn to ride quite well, but switching from the woods pipe to the pro circuit is a shocker as the PC Platinum 2 is anything but smooth, but after you get used to it, and realize the throttle is a lot more sensitive, you can ride it nearly the same outside of this times where you get tossed and give a little accidental throttle input, but you should have one finger on the clutch at all times regardless in order to scrub off the unwanted acceleration potential.

[kdxdazz]

I really disliked the procircuit platinum 2 pipe,so much so that I barely rode the bike, coupled with a lectron that wasn't quite dialed in made it worse, as soon as I went back to the stock pipe everything in the low rpm was significantly better

I was out road racing yesterday on the kdx and the high rpm hit of the procircuit was not there anymore but I wouldn't spend more than 5 percent of my time at full throttle on the road

As an added bonus my tinnitus doesn't get flared up with the stock pipe, my ears would feel sore and sensitive using the procircuit

I think some of the reason people feel such a large gain in power when going to an aftermarket pipe is the stock pipe is caked with carbon on the perforations on the inside which reduces its overall volume and also the stinger area is prone to carbon build up around the weld joins, I soak my stock pipes in hot caustic soda for 2 or 3 days then flush

[Nighthawk016]

I think some of the reason people feel such a large gain in power when going to an aftermarket pipe is the stock pipe is caked with carbon on the perforations on the inside which reduces its overall volume and also the stinger area is prone to carbon build up around the weld joins, I soak my stock pipes in hot caustic soda for 2 or 3 days then flush

Hmm I wonder if i need to do this? My stock pipe feels like it weighs 10lbs.

[kdxdazz]

This is what came out of the procircuit pipe when I first bought the bike, although the previous owner had it running so rich it wouldn't even idle and took me 5 years to be able to get it to idle lol
The carbon doesn't weigh very much but the oil soaked fibreglass carries a bit of weight