My Kdx-Kx Hybrid

Discussion for swapping a KDX motor in a MX frame...
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doctord23
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My Kdx-Kx Hybrid

Post by doctord23 »

Here is my hdybrid story:
I bought a 2004 Kdx 220 motor a year ago that had the piston grenaded. I had to replace one side of the crankcase and replace the crank bearings. I sent the cylinder to Langcourt and the head to Ron for his magic touch. I then found a super clean 2002 KX125 and traded a CRF150 for it. I'm in Cally so '02 is the best year to use. I pretty much followed the cookbook for hybrids and did all of the work myself.

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A few of the things I found along the way that might help others:
1. The new Bill's pipe I bought had too short of headpipe to work. I was able to make some slight bends to an FMF desert pipe to make it clear the frame, radiator and meet up with the silencer. I used some fat bars for my bending leverage tool. I swapped the pipe mounting brackets top & bottom and made an extension bracket for the top mount.
2. I bought a Turbinecore SST silencer for a KX250 and made a couple of brackets and a bend to the inlet pipe to move it forward enough and meet the chamber pipe.
3. I did not cut off the existing motor mounts. I removed the inside half of the lower mount on each side and elongated the mount bolt hole with a dremel to line up with the engine bolt hole. I then made a plate to reinforce it and riveted it in place on the outside of the existing mount. Similarly I made a plate for the top mount and bolted and riveted it to the existing mount.
4. I used a petcock from an '87 KDX. It has a reserve and the outlet pivots.
5. I used the front fender, number plate and triple clamps from a 2004 KX250f for a newer look. I used the '02 stem with the clamps.
6. Rear wheel is the 18" KDX wheel using the KX spacers.
7. Kick lever is also from the '87 KDX, although I may go with a KX250 kicker later.
8. I am running the KX125's TMX 38 carb. I had to lean it out a lot on the pilot jet, but I am very happy with how it runs.
9. I'm using the KX's air box with no mods.
10. I'm using the KX's coil with the KDX wiring and CDI. I removed the voltage regulator since I don't have lighting. CDI is mounted in the airbox.
11. I re-used the KX's water hoses.
12. New kickstand is bolted to the swingarm.
13. I used a GPR steering stabilizer from my KX500. I had to ream out the frame mount to fit the KX steering head.

It is a blast to ride. I still need to soften the front forks a little, but that will happen soon.

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Last edited by doctord23 on 10:36 pm Jul 10 2012, edited 1 time in total.
canamfan
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hybrid

Post by canamfan »

That's nice a very good job. i'm thinking of doing the fork conversion on mine. Enjoy your ride.
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frankenschwinn
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Post by frankenschwinn »

Nice. Love my 02. Seems the easiest model to do.
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scheckaet
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Post by scheckaet »

The air box mod was a bitch though.
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Post by THill »

GOOD LOOKING RIDE !!

You should be able to use your KDX rear wheel on that bike.
I ran a KX on my KDX for awhile....have you a 19 and 18 rear wheel, the axle is the same size...

FYI.....I have a 02 swingarm on my new 03 frame #2 Hybrid build using a KDX rear wheel , hope to have some pic's up soon....
#2 , 03 220 HYBRID..
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Post by MadMax »

Ok good looking bike but..... Why would you swingarm mount a kickstand if you don't have to? I find the kickstand on my bike one of the most dumbass things I've seen on a motorcycle ever. I'm looking at doing the trailtech kickstand ASAP. Just my opinion.
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rbates9
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Post by rbates9 »

>|<>QBB<
MadMax wrote:Ok good looking bike but..... Why would you swingarm mount a kickstand if you don't have to? I find the kickstand on my bike one of the most dumbass things I've seen on a motorcycle ever. I'm looking at doing the trailtech kickstand ASAP. Just my opinion.
There is a lot of talk about this. All I know is the stock stand on my KDX seems to work much better than the frame mounted stands on the bikes of the people I ride with. Well at least until they find the right size rock or stick to put under it to get the bike to stay up on anything but pavement. :wink:
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doctord23
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Post by doctord23 »

Unfortunately Trailtech doesn't make a stand for a 98 to 02 KX so my options were limited. I don't like the look of the clamp-on stands. I've had bikes without stands but definitely prefer to have one.
My Team Green:
2002 KX-KDX 220
2000 KDX 220
2003 KLX 300 DS
1988 White KDX 200C3
1984 KX500 (original owner)
1996 Honda Magna V4
2017 Honda Africa Twin DCT
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scheckaet
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Post by scheckaet »

Trailtech can b modified like i did.
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SS109
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Post by SS109 »

>|<>QBB<
rbates9 wrote:>|<>QBB<
MadMax wrote:Ok good looking bike but..... Why would you swingarm mount a kickstand if you don't have to? I find the kickstand on my bike one of the most dumbass things I've seen on a motorcycle ever. I'm looking at doing the trailtech kickstand ASAP. Just my opinion.
There is a lot of talk about this. All I know is the stock stand on my KDX seems to work much better than the frame mounted stands on the bikes of the people I ride with. Well at least until they find the right size rock or stick to put under it to get the bike to stay up on anything but pavement. :wink:
Same here. My KDX's stand always seem to work just fine while everyone else scrambles to find a rock or a tree!
Youtube Channel: WildAzzRacing
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Current KDX: '98 KDX220
Old KDX: '90 KDX200 -White/Blue
'11 GasGas EC250R
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Post by MadMax »

Well... http://kdxrider.net/forums/viewtopic.php?t=6152 seems to be an option I'd consider.
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scheckaet
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Post by scheckaet »

dats de 1.
THill
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Post by THill »

Didn't read it threw good , I see you got the KDX wheel on it..my bad !!
#2 , 03 220 HYBRID..
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Post by eepime »

>|QBB<[/url]
MadMax wrote:Well... http://kdxrider.net/forums/viewtopic.php?t=6152 seems to be an option I'd consider.
I did something similar but I drilled a new hole to match the one on the left ground it out with a dremel and cut off the extra metal. It still is a little too tall so I may have to remove off of the bottom of the stand next spring. I have to set it in a low spot when I stop or a small breeze will blow it over /IMG_2656.jpgImage
Here is how it looks on the completed hybridImage
Image[/img]
kashola
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My Kdx-Kx Hybrid

Post by kashola »

Nice work! Was just wondering how using the 38mm carb compares with an RB modded 36?
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doctord23
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Re: My Kdx-Kx Hybrid

Post by doctord23 »

I tried the KX carb and it was a low end beast but suffered on the top. It really didn't have the mid rpm hit that I was used to.
This seems backwards as you would think the larger carb would be all on top and low end would suffer.
After a couple of rides, I switched it with a 36mm RB carb and I am happy with this combo.
My Team Green:
2002 KX-KDX 220
2000 KDX 220
2003 KLX 300 DS
1988 White KDX 200C3
1984 KX500 (original owner)
1996 Honda Magna V4
2017 Honda Africa Twin DCT
factoryX
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Post by factoryX »

Image
God, what a great looking bike.
Image
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doctord23
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My Kdx-Kx Hybrid

Post by doctord23 »

Here is where I ended up with a kickstand on my hybrid:
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They don't make a kick-it for the 99-02 KX, so I used one for an 03-05 YZ450f.
The top bolt is the subframe lower bolt.
I made a bracket to mount the lower bolt to the lower chain roller bolt by cutting an aluminum handguard clamp in half.
It sits a little low, but I only rubbed it once this weekend on some very rocky trails with many log crossings.
It folds behind the side number plate just like it does on the YZ and the height is perfect.
My Team Green:
2002 KX-KDX 220
2000 KDX 220
2003 KLX 300 DS
1988 White KDX 200C3
1984 KX500 (original owner)
1996 Honda Magna V4
2017 Honda Africa Twin DCT
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