Ok I am taking the Hybrid Plunge

Discussion for swapping a KDX motor in a MX frame...
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Kman6287
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Update to hybrid plunge

Post by Kman6287 »

Ok, I was able to get the swingarm repaired by a machine shop for $50. They fixed both the broken weld and the "sawing" caused by the chain. They are now in the process of cutting the 9mm off of the swingarm and bushing along with the reaming of the engine motor to 17mm.

I also experimented with the KX boot on the KDX 220 carb. As stated in other posts the KX boot diameter is larger than the KDX carb. I tightened it down on the carb and it appeared to be very secure and sealed, just like I have read from other posts. However, once I tightened it up I held it vertically and ran some carb cleaner around the boot between the carb and the boot. Unfortunately it leaked, so even though it appeared very tight it doesn't seal. I am afraid that if gravity alone can get liquid into the carb it certainly will suck in both dirty air and dirty liquid while riding especially when it creates a negative pressure. I will be doing the modification so that I use the KDX air boot with the kx air box.
2003 KX 220 Hybrid - RB Head & Carb, Dyna Ring, Flexx Bars
500 HORS
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Post by 500 HORS »

Or just epoxy a grooved ring on the carb that is the same size as the KX carb.
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Post by Kman6287 »

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500 HORS wrote:Or just epoxy a grooved ring on the carb that is the same size as the KX carb.
Have you done that? If so I am interested in how you obtained the ring and/or fabricated it as the KDX carb is a unique diameter. I like the idea of the groove as that is definitely needed to seat properly in the air boot. I am thinking that unless such a ring exists off the shelf it probably would require more work to have fabricated then it would to modify the plastic air box as I have the tools to modify the box but not to fabricate a ring.

The ring idea certainly would be a "cleaner" modification if it is possible for me to do.
2003 KX 220 Hybrid - RB Head & Carb, Dyna Ring, Flexx Bars
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Tedh98
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Post by Tedh98 »

How much bigger is the opening of the KX boot than the KDX boot?

I too would like to see pictures of what that ring would look like.
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Post by Kman6287 »

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Tedh98 wrote:How much bigger is the opening of the KX boot than the KDX boot?

I too would like to see pictures of what that ring would look like.
I didn't measure the difference but it is a least several mm's. I will measure the diameters tonight and post them.
2003 KX 220 Hybrid - RB Head & Carb, Dyna Ring, Flexx Bars
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Post by Tedh98 »

If I'm thinking about this correctly, a bigger difference would be better. Otherwise that ring would be really thin and more difficult to machine.
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Post by Kman6287 »

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Tedh98 wrote:If I'm thinking about this correctly, a bigger difference would be better. Otherwise that ring would be really thin and more difficult to machine.
It would have to be thin. I don't have the actual dimensions but from my observations I would think the ring would have to be something like the thickness of a fork bushing, maybe less.
2003 KX 220 Hybrid - RB Head & Carb, Dyna Ring, Flexx Bars
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Post by KarlP »

If it were me, I would use the KDX boot on the KX air box. I've seen examples of what is needed to put the two parts together and it looks "safer" than trying to get the boot to fit the carb right.

Its funny how little things can bite you. On my CR hybrid I used the KDX airbox. It is very different than the CR box and the rear fender was not long enough to reach below below the top of the airbox.

First short ride around the yard and the airbox was full of dirt and grass!

Needless to say, I cut up a another fender and added a couple of inches to the CR fender.
'08 KTM200xc
'99 CR/KDX Hybrid with that RB stuff done to it
KX100 for the boy
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Post by scheckaet »

>|<>QBB<
KarlP wrote:If it were me, I would use the KDX boot on the KX air box. I've seen examples of what is needed to put the two parts together and it looks "safer" than trying to get the boot to fit the carb right.

Its funny how little things can bite you. On my CR hybrid I used the KDX airbox. It is very different than the CR box and the rear fender was not long enough to reach below below the top of the airbox.

First short ride around the yard and the airbox was full of dirt and grass!

Needless to say, I cut up a another fender and added a couple of inches to the CR fender.
+1
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Kman6287
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Post by Kman6287 »

>|<>QBB<
KarlP wrote:If it were me, I would use the KDX boot on the KX air box. I've seen examples of what is needed to put the two parts together and it looks "safer" than trying to get the boot to fit the carb right.

Its funny how little things can bite you. On my CR hybrid I used the KDX airbox. It is very different than the CR box and the rear fender was not long enough to reach below below the top of the airbox.

First short ride around the yard and the airbox was full of dirt and grass!

Needless to say, I cut up a another fender and added a couple of inches to the CR fender.
After my experiment, I planned on going with using the KDX boot on the KX airbox. Just was curious about the ring idea, however it looks like it would be difficult to machine.
2003 KX 220 Hybrid - RB Head & Carb, Dyna Ring, Flexx Bars
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Post by rbates9 »

Sounds like it could be a good project for RB to add as an option to his carb service. Does the KX boot line up well with the KDX carb once the engine is fitted to the frame?
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She's Done!

Post by Kman6287 »

I just completed the KX220 Hybrid project and it was a fun project to do.

2003 KDX 220R Engine
2003 KX 125 Frame
Silver powder coated frame, sub frame, and swing arm
Green powder coated hubs
New graphics
Suspension rebuilt, resprung and revalved for woods riding
Flexx bars
Gutts seat foam and FX gripper seat
Cycra pro bend bark busters
Pro Billet kick stand
New levers
New brakes
New brake lines
Moose Pipe armor
Every bearing new and greased
Custom Oneil fender bag
Pro circuit expansion chamber
FMF KX 250 turbine core II
IMS pro series foot pegs
Coolant overflow reservoir
Fuel filter
Excel 18 inch rear, 21 front with new Dunlop tires and SS spokes
RB Head and Carb mod
Revloc auto clutch
Jeff Fredette kick starter
New top end and KIPS clean
And last but not least KDXRINDER.NET fender decals!

Image

Image
2003 KX 220 Hybrid - RB Head & Carb, Dyna Ring, Flexx Bars
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Post by SS109 »

That turned out really sweet! Now go get it dirty! :lol:
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Post by Tedh98 »

Very, very nice! :supz:
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rbates9
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Post by rbates9 »

That looks awesome! :supz:
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Post by turtle »

Nice, very nice. Some of your KDX parts are on my bike and will live on! I see you've got the picture posting thing down, too! :grin:
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Post by turdsand »

I'm sure this is a question for amateur hour, but I'm wondering why you resprung/revalved the KX suspension for woods riding? Doesn't that defeat the purpose?
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Post by scheckaet »

cuz the MX suspension is way too stiff for trail riding, it's valved to take big jumps.
Doing the hybrid is too get a lighter bike with better ergonomics for a more aggressive riding, no underhang on the forks....some other do it just because they can. :wink:
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Post by Tedh98 »

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scheckaet wrote:cuz the MX suspension is way too stiff for trail riding, it's valved to take big jumps.
Doing the hybrid is too get a lighter bike with better ergonomics for a more aggressive riding, no underhang on the forks....some other do it just because they can. :wink:
One other thing to add - don't confuse doing a wood revalve on KX forks as being the same thing as trying to turn them into KDX forks.
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Post by scheckaet »

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Tedh98 wrote:>|<>QBB<
scheckaet wrote:cuz the MX suspension is way too stiff for trail riding, it's valved to take big jumps.
Doing the hybrid is too get a lighter bike with better ergonomics for a more aggressive riding, no underhang on the forks....some other do it just because they can. :wink:
One other thing to add - don't confuse doing a wood revalve on KX forks as being the same thing as trying to turn them into KDX forks.
I don't think it's possible even if you tried really hard :mrgreen:
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