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Setting up a 2002 KX125 for the trails

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I picked up this bike a few months ago and havent had much time on it yet. My last bike was a DR350s and most of my experience has been with four strokes. I would like to add a headlight and have more useable power. Is there anyone who has successfully converted a 125 for the trails? (Without telling me to buy a KDX200 :lol:).

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my boy runs a cr125 he does trails and hare scrambles. what we did is just soften up the suspension. dropped a tooth on the CS. we havent yet but i assume you could get a FW weight 8-11 oz depending on how hard it hits now.

i told him if he wants more usable power GET a 250!!!:lol::smirk::)

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Ya im definitely down a few cc's! I have about the FW weight but im not quite sure about it. I think the gearing on it is 13-51 so could go to a 12 in the front. What silencer is on your bike? I can't decide between the FMF TC2or the PC nature friendly. Also do you have a headlight on the bike?

Thanks for the quick reply:thumbsup:

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Nah we dont have a headlight, you havta change out the stator and stuff. but you can get a stator for your bike at Rickystator.com that'll enable you to run a light and or lights.

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Disable the bladders in the forks.

I swapped in a KDX220 engine on my 02 KX125.

Awesome trail bike.

Edited by doctord23

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Hey doc, do you have a thread of your swap? I originally wanted a KDX200/220 but this bike came up for cheap. One thing I dont like about the bike so far is the turning radius. Have you noticed this in the trails?

I will look into your idea about the bladders in the forks as they need new seals anyways.

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Hey doc, do you have a thread of your swap? I originally wanted a KDX200/220 but this bike came up for cheap. One thing I dont like about the bike so far is the turning radius. Have you noticed this in the trails?

I pretty much followed the how-to you can find online at onlytrailbikes except I re-used the existing mounts and just added reinforcing plates that were riveted on. I did a few other things differently. I posted my KxKdx hybrid thread on kdxrider.

As far as turning, the way I can carve the 125 chassis on faster trails just using weight change on the pegs is much improved from the handling of my KDX's. I also think the 125 chassis does good in the slow stuff as I can pick a line and it sticks. I swapped the 2002 triples for a set off of an 04 KX250f. They have more offset and i think it made it turn a little quicker. It's a direct swap since they both use the 48mm forks.

I ran the 38mm KX TMX carb on the hybrid for a little while. It had excellent bottom end but lacked top end. I swapped it out this weekend for an RB PWK carb and it lost a little on the bottom but had excellent top end. It also seemed to get a lot better fuel mileage. You would think that the larger carb would hurt low end but it was the opposite.

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I didn't know you could swap out the tripple clamps from an 04? There is a guy near me with 2004 kx 125 front forks w/clamps the swingarm and rear shock for sale. I doubt any of that will be a direct bolt on.

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