Trail Manners?

[Russ]

"My hunch is that you have never experienced a well setup KDX"

I've spent a lot of time on Dave's site. Tried 42 and 45 pilots and 155 and 158 mains in all different combinations along with various air screw settings of about an 1/8 or 1/16 turn at a time. I've run the REV and Torque pipes. Have the Boyesen reeds in. Done a bunch of throttle chops to check the plug (have a 7 in it right now). Have the 12 tooth counter on now. Did the airbox mod.

If I STILL haven't experienced a properly set up KDX because I haven't done the big bore kit or the RB mod, then you're right. Is this what it takes?

You hit the nail on the head with the blubber though. If we're talking about the same thing. The bike just doesn't seem to pull hard unless you twist a 1/2 turn or more and then it rips. Almost seems like I need a pilot leaner than a 42 if you know what I mean, but I just thought anything leaner would be dangerously lean because it doesn't sound like anyone here is going that far. Also, after doing a lot of slow, technical work in the woods, it takes a few seconds of WOT before it "cleans out." So now what do you think? I'd really like to keep the bike. It would be the easiest and most economical thing to do for sure.

Two questions:
Does the RB mod drastically hurt top end?

Does the big bore kit hurt reliability?

Thanks for your patience BRush!

 

[fishhead]

Russ,

The most economical is jetting! If I had a extra CEL needle I would send you one for trial. You could try a CGL in the #5 clip position. if you are loading up try a 38 or 35 pilot. you might try running a step leaner main subject to a plug chop.

I my opinion the loss of top end with the RB mod is not enough to be concerned with for woods work. If you want snap to get the front end up over nasty stuff in 2nd gear this is the way to go but jetting might get you where you want to be.

As for the 220 mod it is a 220 piston in the 200 barrel. ought to do just as well as a 220 for reliability and have a better port timing besides.

This is an art not a science but science improves the art.

just another .02

 

[xpwarrior]

My KDX had a little bog on the low end even after changing the jetting. I'm running a PC pipe and otherwise the engine is stock. What got rid of the bog was setting the KIPS system to open slightly sooner. I just added a thin washer under the screw that holds the check ball and spring. This took off a little spring pressure and lets it open sooner. Now even with the PC pipe its got great lowend and the throttle response is immediate from idle to WOT.

 

[acutemp]

Russ,
Here's my .02 on the situation which is made easier by the amount of good advice posted above.:) I have a KDX 200 on which I have tried about every mod out there including both pipes. I found the results to be much as CC describes when it comes to the pipes. I don't think that anyone is questioning your results but to me at least, something is not right. As far as jetting to lean on the bottom , your bike will let you know by the way it reacts, I would try a 40 pilot. As fishhead has said jetting is the key. You might want to first try some of the needles that have been suggested. Your jetting might be to rich below 1/2 throttle with both pipes, but is closer with the rev than with the torque. Are your power valves working corectly?
Once your jetting is dialed in if you are still wanting a more 4 stroke like bottom end the carb mod works well. If you are looking to lug your bike down farther without stalling a flywheel weight is always an option. For those really nasty riding days I will run my torque pipe,flywheel weight, 12 tooth front sprocket and 36mm RB carb. This setup is not as "fun"IMO as some of the more aggressive setups that I can run, but is much less tiring which is important for an out of shape old guy like myself.:confused: This setup pulls hard from just off idle and works great when traction is needed. Good luck with your decision, but you do have some options.--Dan

 

[teton]

I may be in space here by asking this, but here goes, you seem to have tried some different jetting settings and size's and all the advise you are getting is all tried and true, what is the premix ratio and oil you are using ?

 

[WoodsRider]

Originally posted by BRush
... his ego was bruised yesterday when he was spanked on certain hillclimb by a couple of guys on KDX's :p . Woods, did you have a pang of regret about selling your KDX when you were looking up at us? :)

ps. He's right about that 60+ guy. He can ride me into the ground.

Hmmm, you fail to mention the two KTM's... okay, one and a half... that also made it up the one hill, on a trail I've never ridden before. I wouldn't exactly call that getting spanked. My only regret is not trying it again and taking the wuss line up.

My point is you've got a $6K+ KDX and I've got a $6K GG yet there's Roger, on a stock KDX200 that's probably worth more parted out than whole, mopping up the trail with our butts.

To actually contribute to this thread, I'll throw in my $0.02 worth. I rode a Fredette modified KDX200 for two enduro seasons. I had the Rev pipe, but the terrain where I rode really didn't require the Torque pipe (no big hills). Only when the jetting was dangerously lean did the engine run clean (no blubber). The RB carb mod would probably have taken care of this problem. The engine is NOT a drawback on the KDX. As BRush pointed out, the chasis and suspension are dated, but for the average trail rider/occasional racer it's perfectly fine.

You can spend as much money as you want on a KDX. If I were to buy another KDX I would perform the following mods in order:
1) Suspension
2) Aluminum bars
3) FMF pipe and silencer
4) RB carburetor mod

 

[70 marlin]

taking NOTES !

hey wood's just a bit curious? the handle bar's ??? bend, brand, with? the boy has a set of narrow rethals that are real low© when I ride his bike they feel very strange© your in sight is very welcome:think

 

[Fred T]

CR Hi Bend

Marlin, try the Tag X5 CR high bend and use the Fredette solid bar mount on them. I love mine. Will I see ya at MI Trailfest on Oct 13-14???

 

[MADisher]

Where bouts in MI is this ?

MI Trailfest on Oct 13-14

-MD

 

[70 marlin]

were very hopfull !

if all goes well and everybody is healthy, we should make it© all bike are ready© have been wanting to meet every one© looking forword to it since I missed the first one© buy the way is there any electric hook up for campers ?

 

[Fred T]

MADisher - I P.M.ed you the link for info.

Marlin - you may be able to "bum" a hook up if you get there early and situate your camper near fatherandson's camper, but he would have to verify that because it's his campsite on the club grounds. Send him a e-mail. I've "staked" my claim for a hook up spot for my RV through frequenting the clubgrounds to help with events and trail maintainence but mostly it's rustic camping with juice and water available.

 

[70 marlin]

the son he never needed or wanted: he he

Ya I can relate, or would like to be able to relate©¥owning a spot on ground¤ Its not much of a camper© just a little pop up ¥one light & a furance¤¤ I have lots of extension cords© 200 ft© or so© normally it would'nt matter that much, but one of the boys is recovering from mono, he got in august© I'm going to try to set up the camper to run off a battery© it supose to be able to? but I've never used it© owned since 1986 duh© so keep me in touch

 

[xrsforever]

70 % rider
20 % bike
10 % setup:cool:

 

[WoodsRider]

70 marlin - I had CR-Hi Answer Aluma-Lite bars on my KDX and have also used CR-Hi Rethal and Hebo bars too. I may try a set of Button-bend Renthal or another brand with a CR-double Hi bend next. BRush uses a set of mini-bars that are tall. The benefit of mini-bars is you don't have to cut them narrower. They seem too narrow for me though. However, I don't like my bars under 30" wide.

Originally posted by xrsforever
70 % rider
20 % bike
10 % setup:cool:

Always thought it was more like -
80% rider
10% bike
10% set-up

 

[sixstring4137785]

getting back to the original topic, adding some sauce to your KDX is no different than the next guy putting an exhaust and jet kit into his once "docile and whimpy sounding " XR...Actually the diffence is the thumper ends up being twice as loud as KDX. When you bought the bike did you buy it with "trail manners" in mind ??? Doesn't sound like it. I know I didn't when I bought mine. I think a part of riding is personalizing your bike to your specs. why let an opinion bother you ? I haven't been riding the 220 much since I bought a 500. But the KDX is my first choice for the gnarliest woods ride.
It's easy to ride, forgiving to rider error, and tons of low end. Mine is setup with a rev pipe with no worries about low end.

 

[Russ]

Thanks for getting us back, but I've owned an XR250 and 400 and the wife has been riding a 200 for six years now. The 250 and 400 both had all the possible goodies, but still had the original bore. Pipes, etc. did NOT make them unpredictable or twitchy. I must say that I feel they both had more low end than the KDX. When you're in a tall gear going up a nasty hill climb and the bike just keeps chugging along with no downshift, that's what I would call good low end power. Seems like MY KDX (like many small bore 2-strokes) relies on SOME wheel spin to keep things going or a downshift is needed and then the rear end breaks loose which helps the engine but gives up traction. Sounds like it boils down to a few things.

1. A 2-stroke will always run like a 2-stroke.
2. My KDX is the most carb-screwed up machine this side of the Mississippi.

Spoke to Ron at RB and it seems as though I may go that route if I keep the bike. Sounds like a good guy who is always striving to make a good thing better. The whole project sounds like it was designed for my needs/wants. At first I felt that the mod would only add yet another variable into the mix, but considering the carb comes set-up close when Ron returns it, I felt a little more comfortable with it. Well, that's it.

DAN and DAVE, if you have any more light you'd like to shed on this, I'd appreciate it. I didn't realize that you guys were the "official" testers. Guess Ron plans on doing some dyno runs with various needles?

Thanks!

 

[Fred T]

NOT ACCORDING TO THIS THREAD...

http://dirtrider.net/forums3/showthread.php?s=&threadid=19686

There seems to be trouble jetting with that carb mod.

 

[acutemp]

Official Testers?

Russ, I wouldn't quite call anything "official" but Dave (fishhead) and I have been working on a class project and we are hoping to get a passing grade from the teach, James Dean;) with alot of help from a bunch of people like us that are in search of some alternate jetting setups. No, your bike will never be a 4 stroke but it can be and is one of the most versital trail machines avalible. Let us know how your next step goes.--Dan

 

[fishhead]

I think I know where you're coming from. After one to many mods to increase power and with the stock jetting I found myself with a bike that relied on wheelspeed to make power. Its a great way to ride a 125 mx'r but not the most forgiving thing in the woods. I was ready to get a 4-stroke, any fourstroke, even the dreaded red brand, if it would allow me to hold traction on the slick muddy slabs and root canals that pass for trails. Maybe you know what it's like to be in the soft part of the powerband when climbing a tough section and as you pick up a little speed the power hits and you get massive wheelspin and lost momentum. This always seems to happen just when you need a bit of oomph to clear some nasty hanging root. No fun!

The answer is #1 jetting. Spend 5.00 get a CEL needle and try it in the #3 clip I f you can't get a CEL get a CGL and run it in #5 clip position. Be prepared with a 35, 38 and 42 pilot. Sharp jetting improves throttle response which is not "more power" but improved control of the power you have. The quicker the engine responds to throttle the less modulation you have to do and the easier it is to find and hold traction. When you have traction you can use the 2 stroke power to squirt over or past obstacles. If this doesn't do it for you try the RB Mod it will improve throttle response on the 0-1/2 throttle area.

Correct jetting opens up a aspect of riding that you may not have experienced in a small bore bike such as lofting the front wheel over obstacles on relativly slow second gear trails and then squirting up a smooth section with enough momentum to coast over trouble spots The bike pulling strong from idle in second or third gear. The mod and the correct jetting and I emphasize correct jetting has changed the way I read trails. I now look for ramps to launch over things rather than plough around or over them. As a result I am not as tired at the end of a long ride.

I know it an agonizing process to consider spending money on a platform that you aren't sure will turn out but there is some success to be found here.

 

[MisShift]

220's as well?

This has been the best volley of reply's I have ever seen. So much good info that HOPEFULLY I can use. What I mean is, can I apply all this information and part names such as the CELneedle and such to my 98 220? I have all the mods that Russ has. PLEASE tell me It'll work! :confused:

 

[fishhead]

I have not done any testing on a 220 with a 33 mil carb but if you want a hot rod bore the carb

 

[acutemp]

MisShift,
My testing is also limited to 35mm and larger carbs on my 200. For a few bucks though it would be well worth a try. --Dan