kx 125 trans in kdx

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muddymike
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kx 125 trans in kdx

Post by muddymike »

Anybody put kx trans in kdx? If so thoughts? I'm curious about a close ratio trans on kdx for woods and track. I can climb any hill in 1st on my kdx 200 and 6th gear is nearly unusable. I'd rather have 1st gear be like granny gear and 2nd and 3rd get me around without having to switch too much.
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Re: kx 125 trans in kdx

Post by MaverickAus »

Bigger rear sprocket and longer chain. Just a suggestion.
muddymike
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Re: kx 125 trans in kdx

Post by muddymike »

Already have 1 tooth bigger in rear. Not that 1 tooth on rear makes a difference. More so lookin for gear overlap instead of either bein in right or wrong gear. I also have air atriker carb which took away some length in each gear
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kx 125 trans in kdx

Post by Willbilly »

1 tooth bigger in the front did me great on my 220 keeps up with every bike on race day.

I struggled with 2nd being too low and now it's great. I mostly ride 3rd gear with occasional 2nd and 4th
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Re: kx 125 trans in kdx

Post by 6 Riders »

I'm with the 14 tooth front sprocket. Seems to me that it helped with the big gap in the transmission.

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kx 125 trans in kdx

Post by K50X200 »

muddymike wrote: I'd rather have 1st gear be like granny gear and 2nd and 3rd get me around without having to switch too much.
Try a 12T sprocket up front... I've been running one for a couple years, and for me it works just about as you've described! :cool:
"00 KDX200 - Baja Designs D/S Kit, '03 KLX300 Forks, KB5 Suspension Mods, Keihn 35 ASQV, Boyesen Rad Valve, Gnarly Woods Pipe
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kx 125 trans in kdx

Post by pumpguy »

To really answer your question, first and foremost you need to check the fit. I know of no one that that has done what you propose, so you will have to learn how the KX shafts and gears fit into the KDX cases. Maybe a friendly KX owner can help.

If you find the shafts and gears fit, and the shift forks and their rods also fit and everything functions, you can use the whole KX gear set, or crunch the numbers to see what ratios you can come up with.

Back in the 4 speed box days, there was one bike where we had a choice between using wide ratio road gears, which gave a bottom gear reduction of 3.3, and close ratio gears, which gave a bottom gear reduction of 2.42. Using a combination of of the 2, one guy crunched the numbers and found by using a lay shaft and main drive gear from the opposite set, (I forget the exact details now) he arrived at a 2.9 bottom gear ratio.

This is an interesting project, and may allow you to come up with a set of ratios that best suit your needs.

I hope this information is helpful. If you are successful with getting different transmission gear ratios, let us know.

Good luck.
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Re: kx 125 trans in kdx

Post by KDXGarage »

When you researched bearing inner diameters between models, what did you see?

You did check that out first, correct?? :shock:
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muddymike
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Re: kx 125 trans in kdx

Post by muddymike »

Jason wrote:When you researched bearing inner diameters between models, what did you see?

You did check that out first, correct?? :shock:
Ya I saw what your talking about when I researched it. But just to make sure we're talking about the same thing, what did you see?
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Re: kx 125 trans in kdx

Post by KDXGarage »

For 2000, different left output shaft bearing ID.

I know that on some of the 90's KX250s, one can replace individual parts / pairs?? to get a lower first hear from a 98. Also, swapping in KDX250 gears into KX250.

Like another member said, I have never read of it being done.
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Re: kx 125 trans in kdx

Post by muddymike »

Jason wrote:For 2000, different left output shaft bearing ID.

I know that on some of the 90's KX250s, one can replace individual parts / pairs?? to get a lower first hear from a 98. Also, swapping in KDX250 gears into KX250.

Like another member said, I have never read of it being done.
Ya. Truthfully, me neither. That's why I asked (I googled 1st with no results then figured I'd check here). I'm familiar with people swapping years on kx 250 (I have a 2000 kx and people swap out the input shaft for '98 for lower 1st) and swapping kx 250 trans with kdx 250 trans (it takes trans and forks). So just wanted to see what info I could get, looks like we've come to the outcome. It's way cheaper and easier to just deal with the kdx trans. Any issue I have with the wide ratio would probly just be matched with a different issue on a close ratio trans.
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