KDX200 won't rev

[DonJuan]

A new to me KDX will crank and idle fine, but bogs out as soon as you put it in gear. New plug, carb rebuild, new float, calibrated the float level, moved needle clip from 1 through 5, repacked silencer, changed main from 155 to 150 and back again, adjusted air screw, etc... it revs better in neutral, but just won't go.

The one or two times it did go, it wheelies as soon as it gets on the pipe, so I don't think it's rings, but I haven't checked compression yet.

Any ideas?

[Buzz]

Kdx 200, 220?

I will go ahead, and say it.  Piston and rings. If it is a 220 it needs a new piston from the show room floor. The stock one will break. I broke one mid race. It sucked. Some poor fool still rides that bike :lol-049:

The other issues are case vacuum leaks, and kips mechanism.

Regardless build the top end. It is super easy.

[DonJuan]

'89 200

[kylepeterson]

A new to me KDX will crank and idle fine, but bogs out as soon as you put it in gear. New plug, carb rebuild, new float, calibrated the float level, moved needle clip from 1 through 5, repacked silencer, changed main from 155 to 150 and back again, adjusted air screw, etc... it revs better in neutral, but just won't go.

The one or two times it did go, it wheelies as soon as it gets on the pipe, so I don't think it's rings, but I haven't checked compression yet.

Any ideas?

check the basket for notches, it will die when you put it into gear if it's notched.

sounds like someone may have broken a kips sub valve, and/or glued it into the wide open position.

make sure your reeds aren't shattered, then pull the head and check the sub valves.

I know that guy that's still riding Buzz's old kdx. he loves it.

[yamahamer]

Yeah, what Kyle said. Sound like the clutch to me. If the reeds were bad it wouldn't get on the pipe.

[DonJuan]

Haven't dug into the clutch yet, but I did find a broken reed. I figured i'd check out and clean the KIPS, and there ok, and clean as a whistle. Since the head is off , I might as well do the top end. When I'll get it all back together I'll let y'all know what worked.

[kylepeterson]

Haven't dug into the clutch yet, but I did find a broken reed. I figured i'd check out and clean the KIPS, and there ok, and clean as a whistle. Since the head is off , I might as well do the top end. When I'll get it all back together I'll let y'all know what worked.

it's probably just that reed. i've tried about five different reed sets to try and feel a difference, but the butt dyno doesn't know a difference. literally the only way to tell a difference is to take on full petal off and try to ride it again.... yep it revs and idles, , but it gets richer and richer until it gets very low and won't respond, or can't pull a sick whore outta bed.

congrats, i like kdsexes !