KDXRIDER.NET

Hi everyone,

I was out riding with some friends last weekend and got to ride my buddy's 2000 YZ125 for the first time; I noticed that the YZ has a much more progressive throttle than my 2001 KDX200. I know that 75cc's plus a power valve goes a long ways for adding low down grunt to the KDX, but my bike is almost violent in its power delivery and there were times when we were out where the bike was riding me and not the other way round. I basically skipped using 1st gear for most of the weekend, instead using 2nd and 3rd. We were on were predominately class I and II ATV trails, and I used maybe 1/8 of a turn on the throttle for anything besides powering down the wider Jeep trails. Is it normal for the bike to pull like a freight trail immediately off idle?

Adding to the mystery, I was trying to adjust my idle and the screw appeared to have no appreciable effect on the idle speed of a hot engine until a point where it just died. I am pretty sure the previous owner said that he kept the jetting stock after he put the Gnarly woods pipe on.

If the jetting is stock then you need to go through and jet it correctly with the exhaust change. The fact that your idle screw does nothing suggests its time to rejet anyways. The YZ is going to feel a bit tame compared to the 200. Jetting will help the response. On easy ATV trails 1st gear will be basically useless for most riding.

The KDX will feel a lot snappier than any 125 just due to the low end torque it has. Be happy you're not ridding a 250 or 300 two stroke! 1st gear has always been pretty useless for me unless riding hike-a-bike stuff and that's with 13/48 gearing. I always start off in 2nd gear.

Definitely get that jetting sorted. You can help control the snap of the engine with the air screw if the pilot jet is correct. Of course, you can always control the snap with good clutch control. I've found that KDX's have a very narrow clutch engagement range compared to a lot of bikes so it makes it a challenge but can be learned. I'm thinking of doing the KX125 clutch arm mod to help increase the engagement range at the lever.

I'm wondering if part of my issues are down to technique, but it feels like even when I'm trucking along at 20-25 mph in 2nd or 3rd a blip on the throttle is causing the bike to surge forwards hard enough that I'm standing on the front corner of my pegs and bracing with my arms to stay on. I was having a hard time getting a steady throttle input and not getting too much power coming out of a turn. I had a few hairy corner exits and a low side because I couldn't feed the throttle in evenly. I am really new to this bike, this is probably my 4-5th day of riding dirt where I've been riding street for 3 years.

20-25 in 2nd or 3rd gear? No wonder it feels snappy! Dude, up shift! You have 6 gears for a reason. Use them!

I agree, higher gears and staying lower in the revs will help tame the hit. Is this your first two stroke? Get the jetting right and use the clutch. It can take it.

This is my first 2-stroke. I think I'm trying to match my RPM feel to that of my road bike, which probably means I'm way higher than I need to be for my speed. One of my first rides was along much slower trails and I was really impressed with how low I could let the RPM go without the bike dying. I'm still going to tear apart the carb, just so I can make sure of what I have for jets, but I'll need to keep that RPM difference in the back of my mind while I'm riding.

Watch a few Youtube videos of others riding similar terrain. Listen to what their engines sound like, then compare to what yours is sounding like.

it's definitely a change going from street to dirt. For a 2T you REALLY need to learn clutch control, it is the heart of riding a 2T efficiently. If the hit is throwing you off then go up a gear and train yourself on how to slip the clutch to bring your RPMs up when you do need to get on the pipe. It all comes with riding more, so the mosre seat time the better.

Have you removed the snorkel or cut the airbox? If so this will be your problem, I put the snorkel back in mine and it gave it a less snappier feel and much more tractable

Let me repeat: “ Dude, upshift...”.
Sounds like you are riding in too low of a gear. Not only will you gain control but you’ll ride faster as well. I don’t mean lug it around the trails, but riding in too low a gear just produces a lot of wheel spin and rocketing off the trail.

Yeah, on ATV trails I would be in 4th, 5th, and 6th gears most of the time. Learn to use the torque the engine has so you don't have to rev it so hard. Traction will be better and it won't be so snappy.