KX transmission swap possible???

[wfopete]

Is there any KX125 or KX250 gearsets that will fit a late model KDX200 (1995 or later)?

Thanks

[SS109]

None that I know of. The '95+ KDX was based off of, IIRC, the '92 or '93 KX125 engine. That would be the only possibility I can think of. Curious, why would you want a close ratio gearset?

[wfopete]

Asking for a friend who has a hybrid and wants a more usable 1st gear and tighter ratios for his application.

[Chuck78]

That's an unusual request, as those with motocross bikes with engines and suspension valving converted for woods use are always complaining about the close ratio gearboxes being a poor fit for woods riding! Or the YZ250X "wide ratio" 5-speed gearbox being not wide enough for both hard enduro goat trail work as well as attacking the fast wide open sections of trail/fire roads in between technical sections, as it lacks a 6th gear!

I checked out of curiousity, and the 89-2006 output shafts are the same shaft part number on KDX200/220, but the input gearbox shaft is a specific H or E series part. So SS109, I'd say maybe the gearboxes were originally based on the '88-'89 KX125? I knew the cranks, rods, pistons, and crankcases were common between the E-Series and H-Series, so this made me scratch my head on the KDX gearbox being designed after the 93-ish KX125. Perhaps the gearsets were revised based on those years of 125 which you stated?

Before anyone gets confused, literally almost EVERYTHING in the CLUTCHCASE are is different between the E-Series and H-Series, as well as the top end and power valve, aside from the piston, but you can swap a clutchcase and internal components +220 or 200H top end onto an E-Series "bottom end," meaning the crankcases only, not the clutch case components.

I'd question why someone would build a hybrid with a woods engine, but want non-woods characteristics out of the woods engine...??? To each their own!