No power until on the pipe

Rev

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#1
Guy`s,I rode my stock 00 kdx200 for a year without any mods so I could get use to riding a dirt bike. Now I have done the mods.Installed Boyesen Reeds, Air box cover, FMF Gnarly Rev pipe, not the Gnarly torque pipe( from the suggestion of the local shop. they told me it was the same pipe but revs higher) TCII power core. 12t front socket 48pilot 155 main air screw out 1.2 turns. Now to me it feels like it has no power coming out of a tight turn in second gear until it gets up on the pipe or I have to pull in the clutch slightly to get it up on the pipe. By the time this happens I get past by everone. Is the problem the bike or bad riding habits by me?
 

Mikeb

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#2
Sounds like your dealer might have given you some "bad info". The torque pipe and the Rev pipe are distinctly different. Just look at a photo of them and you can see the difference. The REV pipe is made to increase the top end and the Torque pipe is built to increase low end and mid range power. I ride a 98 KDX 200 with torque pipe and I have ridden a similar bike with a REV pipe and the differences are HUGE. The REV pipe felt like a 125 and had to be ridden hard and "on the pipe" to make it perform. My torque pipe can be lugged all day and will rev out pretty good on top end also whan needed.

My advice to you is to see if you can ride a 95 or newer KDX with a Torque pipe and see if this fits your riding style better. Heck ... Maybe the dealer would swap with you ... "Since it is the same pipe".
 

Canadian Dave

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#3
Your jetting will account for at least some of your problem. At first glance your pilot and main jet look too rich. Follow the link below and have a look at the carb tuning article. Once you have the jetting optimized it will certainly run better. I'd suggest you start with something in the 42 pilot, stock needle in the second from the top clip position and a 155 main. Remember to take a plug reading at WOT to insure you aren't running lean.

Mike's right a rev pipe will never have as much grunt off the bottom as a torque pipe but yours can be made better than it is now.

David
 

Rev

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#4
Mike, You are right on. I do have to ride this like a 125. That was my first thought but wasn`t sure. It does have great power from mid to top end. Dave, I have read your tuning tips, First place I went to when I started doing my mods. Great Web site. I started out with a 42 and to me it was lean, the bike ran ok but the plug was white. Installed a 45 and the plug was getting some color to it.Thought a 48 was on the safe side.Is it better save than sorry?.But doesn`t the air screw also give you a guide if you are running the right pilot jet?. mine is 1.25-1.5 turns out. Thanks guy`s for the repley back. P.S.Listen to the just KDX web site and not the partsman behind the counter, who I think has never lifted a leg over a seat before.
For sale One slightly use Rev pipe.
 

Mac

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#5
Rev,
The pilot jet will not affect the color of the plug when the plugchop is done correctly. The plug color is used to adjust the main jet. The pilot jet should be adjusted for throttle response.

Dont sell your Rev pipe just yet! I have the exact same bike and when I installed my REV pipe it took a few jetting changes to get it right. It seemed to have no bottom end. I too used a 48 pilot and a 155 main because it felt lean on bottom but still had no snap. I finally changed my clip position one richer and my bottom end was back, I then leaned the pilot back to a 42 to clean up the bottom and lost no bottom end. I changed my jetting to 42pilot, 152 main, needle in middle (this made the biggest change) and the a/f screw @ 3/4 turns out. My bike is now a rocket, I cannot tell you how much of an improvment one needle clip made. Temps are 70 to 80 here in NE and I will switch to a 155 main in the winter.

The a/f screw can make a huge difference in throttle response, DONT just set it to highest idle and forget it this will NOT be the best setting. Turn that screw until your bike stands at attention when given WOT. Most a/f screws on the 200's like to be between 0.5 and 1.0 turns out.

CDave is right, keep at the jetting till you get it right and you will be rewarded. My bike is like a 250 down low and a 125 on top. :)
 
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Rev

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#6
Mac,WOW, Thanks thats great news to me and my wallet. I was adjusting the air screw to hightest idle. I was afraid to run the 42 thinking that in tight trails that it might be to lean and smoke the motor, But I`m heading out to the garage tonight to do some swapping. Thanks
 

Mac

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#7
After the jetting session make sure you do a PROPER plug chop to check the main jet. Most 200's will run between 152 and 158.
 
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#8
I have a 2000 KDX220 with a Rev pipe and similar complaints. Do you think the same carb set ups recommended for the 200 would help the 220?
 

Canadian Dave

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#9
Mike,

No. The 220 uses a 33mm carb and the 200 a 35mm carb. The jetting wont be the same unless you've had your carb opened up to 35+mm or you've installed a 35mm carb off a KDX200 etc.

The fact that optimizing your jetting will improve power delivery is however the same regardless of what bike you ride. You should have piles of grunt with a Rev. pipe installed on your 220.

David
 
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#10
Mac, I have a 1995 KDX 200, rev pipe, silencer, and airbox mod - I'm going to re-jet with your specs as a starting point, are you using the stock R1173K needle, or have you replaced it with the R1174K?
 

Sage

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#11
A rev pipe and compression seems to make a nice fat power band??? maybe I'll post some dyno charts at my site if I can figure out how.
 
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#12
Ok, I had the needle part numbers mixed up in my last response... but I changed the jets this morning to the 42 and 152 like Mac suggested, old jets were 48, and 160. The first test run was crap, the motor was sooo skippy I couldn't even get out of second, so I went to get my old jets, but they weren't there. I looked around and saw my dog was just finishing up the last bit of the manilla envelope that I had carefully put the used jets in. Stupid dog, eh, what can you do though? Since I didn't have my jets anymore, I decided to play with the needle adjustment, took it off of the second from the top, and put it in the middle adjustment, took the bike for a ride, and WOW! Its like my KDX was just freshened up! I love this bike, and I love this site! Thanks everyone!

P.S. bike is a 1995 KDX200, FMF Rev w/ FMF silencer, 13/49 gearing and a 120/100 Dunlop 752 on the rear
 

Mac

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#13
Yes Brian, as I said in my original post the needle is key. I also use the stock needle. I've been running this setup since spring and my bike rips off idle to the top. Im not sure how it will act come fall so I would get a 155 main on order along with some dog biscuits. :D

Where did you put the a/f screw? try 3/4
 
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#14
I tried the suggestion of moving the clip 1 notch richer which on my bike was 1 step rich from the middle. I had to go to 1.5 out on the air screw and the bike is much stronger mid range and didn't bother the top end at all. I have a 2000 KDX220 with an FMF Rev bike. Thanks for all the help.
 

Mac

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#15
Mike
Glad to hear you made an improvement on your bike BUT be careful, the jetting specs in this thread are for a 35mm(kdx200) carb NOT a 33mm(kdx220) carb. Try THIS LINK for more info on your bike.