KDXRIDER.NET

So, I absolutely hate myself for selling my 200. I have been dying to buy another bike for the past month or so. Keep going back and forth two stroke vs four, 125 vs. 250 vs. 450, Honda vs. Kawi, vs Zukes.... I couldn't make up my mind and it was driving me crazy. So, I just decided to say F-it, I am just going to built exactly what I want, the perfect woods bike...

SO IT BEGINS! Picked me up a 2005 KX125 last night for $900 that is in need of a top end and TONS of TLC (I feel this was a good deal?):



It is always hard for me to buy used bikes because I feel like 90% of the clowns on C-List don't know how to take care of their bikes, especially like I tend to do. In addition to needing a top end (zero compression, i can push the bike while in gear with little effort), there is black spooge all over it, the plastics are horrendous, needs rear wheel and linkage bearings, and its missing a bunch of nuts and bolts here and there. The shocks all seem to be in good shape though, no leaks from any seals, no frame cracks or dents that I can see as of now, rad guards are completely in tact, bars are straight, its not all bad.

Whining over (I always have to complain about something), I CANNOT WAIT TO GET THIS PROJECT GOING!!!! I've been reading build threads on here like crazy (still have more read/learn) and I feel like I have good grasp on everything that will need done. I plan to try and make the bike look like a brand new bike that was supposed to have a KDX motor in it (all new plastics, probably new factory graphics, silver powder coat on the frame, polished swingarm and subframe with clear powder, etc...). Motor will get a full top and bottom end rebuild, plan to keep everything stock for now, upgrade with RB stuff later down the road. Also did some reading on the Rekluse set-up that Harry was so kind to investigate, figure out, and share with all of us... DEFINITELY plan to do that swap, and will probably send the shocks out for revalve/rebuild (unless I decide to take this on myself also, don't know yet)

This will be my winter project, I do not plan to have it completed until next riding season, so updates will be slow, but I will have lots of time to do everything right and make it just how I want it (I am a nerdy mechanical engineer that is also a perfectionist, it takes me forever to do anything, including typing this post haha).

Two Questions:

1. I would like to get away without buying a complete KDX if possible. Is this do-able? Or would I just be asking for headaches? I feel that all I need off the KDX is the complete motor, all the wiring (need to find out what all wiring stuff I would need), airbox, boot, and a new pipe. Is that correct? Or is there other stuff that I need off the KDX? I figure I can pick these parts up here and there off ebay and craigslist.

2. Opinions on 200 vs 220? I wanted to go with an H-series. I thought I had heard that the 220 had more bottom end? But for some reason I remember being happy that I had a 200 instead of a 220, but I cant remember why (maybe due to the ticking time bomb 220 piston?). I basically only ride woods, very rare for me to hit up an MX track. The woods riding I do ranges from super tight technical single track, to wide open gas/logging roads/paths. Any input you can give to help me pick would be much appreciated!

The 200 is a touch better in the over-rev department, and the 220 is a touch better in the low end and a bit more linear overall. I personally prefer the 200, but lots of guys like the torque of the 220. You can probably get away without a complete KDX, although it would make the job easier. I think your parts list is pretty solid so far. You'll also need the carb, obviously.

Ive searched around for just the parts needed for a hybrid build instead of buying the full bike and its not worth it. If you have the space to store the bike buy a complete one you can sell off the extra parts to offset some cost of the build. Around here 1 or 2 KDX's hit clist for 500-800 every couple months usually running good with rough body's.

I like the 220 better than my 200 now. The 200 is a little faster in the open stuff. The 220 goes from corner to tight corner more efficient because of the extra mid range. I am using the rev pipe too.
Good luck with you build 04\05 chassis is easy one to do.

Your going to have fun with this Tyl3r. Being a mechanical engenear is going to help as you know stuff. Me I know nothing, it's exciting that way.

kx200 wrote:I like the 220 better than my 200 now. The 200 is a little faster in the open stuff. The 220 goes from corner to tight corner more efficient because of the extra mid range. I am using the rev pipe too.
Good luck with you build 04\05 chassis is easy one to do.

+1 ,,, but a decent 220 engine / bike is much harder to find

A properly modded 220 is a serious woods bike :}

I have built 2 similar hybrids:
First one by buying most parts including a used 220 engine that needed work from a guy parting out a whole bike. Then buying additional parts as needed and selling the KX parts that were removed.
Second one was built from two complete good condition bikes and then parting out the remnants of both.
I posted a spreadsheet showing the net costs of both projects on here if you want to look at it.
Here is the link:
http://www.kdxrider.net/forums/viewtopi ... 23#p113947

Of the two, I prefer the 220 version for my single track riding.

Your bike looks similar to mine with the same grafics. Black frame and wheels changes it though.

I sold off my KDX parts and more than made up for the cost of the KX rolling chase.

Don't know if this is redundant,. Either way go for a "H" model engine.
Pipe and radiator fit will be much easier.

Thank you all for all of your input, much appreciated! I am thinking I will go with the 220 motor, I ride a whole lot of tight stuff and really want the extra bottom/mid range power.

Storage is my issue with having two bikes. I will be building this in my single car garage. To have room for everything, I'm going to have to clean off those shelves behind the bike in the pictures above in order to have somewhere to put parts haha. The more and more I think about it, I really should get a whole second bike. I will be on the lookout for one. There are few nice ones of c-list in the 1200-1700 range on the local c-list... just waiting for the right one to show up, and putting the cashola together to buy it when it does.

doctord, thanks a bunch for that spreadsheet, really helps to put things into perspective. I was thinking about making one of those myself! Looks like buying a second bike really helps to offset the cost of the build due to selling parts off of it.

Something I am dying to know... how come everyone switches from a 19" rear wheel to a 18"? Wouldn't the larger wheel/tire help with getting over obstacles? I need to know the reasoning behind this lol.

Tyl3r wrote:
Something I am dying to know... how come everyone switches from a 19" rear wheel to a 18"? Wouldn't the larger wheel/tire help with getting over obstacles? I need to know the reasoning behind this lol.

The diameter of the two tires is nearly the same. The 18 tire has a smaller diameter rim and a taller/wider sidewall. This helps to minimize pinch flats vs the 19 tire which has a larger rim and a smaller/narrower sidewall.

The 18" kenda equilibrium I've got on my kx250 is taller than any 19" tire I'd run on that bike. You can run lower pressure in the fatter tire giving you more traction.

Point taken. Thank you!

Now, I see most people buy a new rim when they run an 18" wheel. Could I use the KDX rim with the KX hub if I get shorter spokes? Didn't know if they would have a different number of holes or something? Just seeing if I could cheaply make the switch.

Some of the KX hubs are the same as the KDX hubs. I am currently having a KX hub laced to my KDX rim for use on my KDX. So that might be a straight across swap, with proper bearings of course.
The KDX rim does lace to KX hubs as well. Like you said, use shorter spokes.

Tyl3r wrote:Now, I see most people buy a new rim when they run an 18" wheel. Could I use the KDX rim with the KX hub if I get shorter spokes? Didn't know if they would have a different number of holes or something? Just seeing if I could cheaply make the switch.

I'm sure the hub on your '05 is the same as my '04. I laced a KDX rim to my kx hub with no problems.

Awesome, thank you both!

I've never laced and trued a wheel before. I'm gonna watch a bunch of YouTube vids and see if I feel like I would want to give it a try or take it someplace (always hate letting someone else work on my stuff tho).

My buddy and I have been getting into powder coating on the side and he just bought some gold powder. Maybe I'll try and make the hubs gold... since I know I can powder coat everything myself pretty cheaply, I keep going back and forth in my head about what kind of color scheme to go with haha I worry more about that than I do the actual engine swap portion of it haha I got that part figured out at least!

From what I can tell the KX and KDX hubs are the same for lacing up. The 2001 KX hub has two wheel bearings on the sprocket side. I got a Mores I think it was SS spoke set off eBay already made up for KX hub 18" rim.

Lacing up,is not that hard after you get the patten. When it comes to truing the rim it's easy if you can hold a old swing arm in a vice hold the rim in it. If you can bend up wire and use the ends as pointers to check run out and wobble you can get within spec which is a generous 2mm

Make sure you get the offset right before you go too far.

I learned that the hard way, got it all done and then realized my offset was "off".

Good point with the off set Tedh98. Apart from it looks right do you know any markers to go by for off set?

I would imagine they would state the recommended offset in the FSM for the KX (gotta get me one of those...)

I've watched some youtube vids and came to the conclusion that I am going to take these wheels apart, powder coat the hubs, nipples, and rim, and put back together. Doesn't look very difficult, just time consuming.

I made my first bit of progress on Saturday. Got the garage cleaned up and few shelves cleaned off for parts (needed to be done before I could start). Took the bike apart and pulled the motor:


Wasn't too bad, only one big surprise... the brake side chain adjuster has a helicoil installed that is extremely crooked... really bummed out about it. I am further bummed because the 05 swingarm isn't the same as any other year or size KX's, so finding a replacement won't be easy. Going to look at maybe removing the helicoil, having it welded up, and redrilled/tapped. Unless anyone on here has any better ideas?

Other than that, I know I need rear wheel bearings, linkage bearings, swingarm bearings, a nice new pivot bolt and rear axle, sprockets, chain, air filter. I can't wait to have a brand new bike when I'm done

After I pulled the motor, I put it back together so that it was one, easily moveable pile of parts. I think now I am going to take it apart completely and put it on the shelf. Then I can start to powder coat things like the hubs, trees, nipples, rear subframe, foot pegs, bar clamps, calipers, and maybe the swingarm too if I figure out what to do with the chain adjuster. I am thinking black frame and swingarm, with a bunch of gold accents, and green plastic, with black number plates/fork guards. Trying to look a little different, but don't want it to look tacky.