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next up was getting the pipe installed.

It didn't quite fit in between the wishbone part of the front lower frame. So I had to grind the welds a bit:




And that was just enough to fit:

Next was the radiator.

Rather than pay $50 for Dr D radiator lowering tabs, I made my own cheapo tabs out of aluminum.




I couldn't find any dealers with the CR250 T fitting for the radiator hoses. So this is an experiment. These fittings are for drip line. They say on them "for gardening only, not for hot water systems." So we'll see how that goes. They'll probably melt and leave me stranded in the middle of nowhere, and dissolve into my engine as well. I hope not, but we'll see. This is a temporary fix until I get the honda part.

Then I slowly started putting it back together until I ended up with this:

got a ton done today, but the bike still isn't finished. it's 95% there. I lost my slide spring (due to my messy garage).

Unfortunately the chain I ordered was too short. A stock kdx chain is a 108. I thought I read that a stock CR125 chain was a 110, so I figured a 112 would be plenty. I was wrong, a stock CR125 chain is a 114. I'm pretty sure I need a 114, but I'm going to order a 116 just to be safe.


Here's what's left:
- install/adjust throttle cable
- adjust clutch cable
- bleed rear brake
- mount and route electronics (really only a 5 min job)
- install gas tank
- make pipe mounts
- put oil in it.
- get a new chain

You're getting there!

You really didn't end up with much room for the pipe to pass through the frame, did you? Do your pipe springs contact the frame? It looks like they might. I wonder if an E series engine would have allowed you to rotate the motor forward just a smidge more to get better pipe clearance...probably wouldn't have had to notch the frame, either. Of course, you end up with all the nasty E series powervalve problems, and having to heavily modify an H series pipe to fit it, too...

Anyhow, your project is looking great so far.

thanks for the encouragement dfeckel. I'm so close yet so far away. The pipe is the only part that isn't dialed right now. Once I get those dents put in it where it's contacting the frame, it should be golden.

I went for a ride on my brother's WR250F today, and I can't wait to have the CR suspension with the KDX motor.

A few days ago I got the blinkers working and fired her up. Took a couple kicks, but she runs now. No crazy amounts of vibration from the pipe either.

Still a lot of little kinks to work out, but I'm getting excited.

to-do list:
- put some spacers on the lower motor mount
- get a new radiator T fitting from evco
- finish wiring the headlight/taillight/electrical
- secure wires, find a place for the relays
- bleed brakes
- install chain
- find a solution for the kickstart (its hitting the pipe and frame)
- fix the petcock so it doesn't hit the water outlet in the head
- put the plastics back on

Since the wiring is all in the airbox, I wrapped it in masking tape, then duct tape. I'm worried about the voltage regulator. I'm afraid it'll get too hot being inside a paper towel, surrounded by a plastic bag, surrounded by duct tape. Anyone have any thoughts on this?

Here's the wiring:




Then I took it down to Jiffy lube, passed the safety inspection and took it for a ride.

This is a seriously fun bike. I love the way it handles. It feels quicker than the KDX felt , and the suspension/handling are amazing. I don't want to change a thing on it, it's a really fun bike. Since I was used to the KDX powerband (or lack thereof), it felt like a familiar bike, only with incredible handling. I can't wait to take it up the canyon next week.

She's done! Here she is:

only thing left is to get a kickstand, install my bark busters, and dent the pipe up so it isn't touching the frame anywhere. Oh yeah, and ride the crap out of it.

I'm thinking of getting the RB head and carb mods on it this winter when I can't be riding it anyway. We'll see.

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sixstringsteve wrote:
I couldn't find any dealers with the CR250 T fitting for the radiator hoses. So this is an experiment. These fittings are for drip line. They say on them "for gardening only, not for hot water systems." So we'll see how that goes. They'll probably melt and leave me stranded in the middle of nowhere, and dissolve into my engine as well. I hope not, but we'll see. This is a temporary fix until I get the honda part.

Sounds like this didn't work out, since you were getting a new T later. You should be able to get a plastic heater hose tee for 5/8-in hose from any auto parts store for a couple bucks.

sixstringsteve wrote:ok, thanks chopper, that makes sense. What do you think about running a single tube from the head to the upper left part of the radiator? Then I'd cap off the upper right rad tube.

Just like FRECNDY said here:

http://kdxrider.net/forums/viewtopic.ph ... 7&start=40

FRECNDY wrote: Seems like it'd be pretty clean to do it YZ250-style. One from the head to top of left radiator, two crossovers, and out the bottom of the right radiator to the water pump. The inlet at the top of the right radiator could either be capped or welded. Less pressure loss for a given flow rate than the KDX routing, and should be equal flow through left and right radiators, unlike the Honda which seems like it would favor the right radiator.

If you click the linky, you'll see that post is quoting another post that said the CR radiators have two crossovers. That's technically true, I guess, but I couldn't see the upper hose in SSS' pics, so I looked up some radiators on Ebay and the upper crossover is just a 5/16-in for air bleed. Not going to flow enough coolant to make the YZ concept work. I think the way he did it is best.

Looks awesome! And plated, to boot. Nice work, and thanks for documenting the process.

Oh, and I can't recommend the RB mods enough. Excellent gains in the low-end with tractability all the way down to 12 rpm. It's good stuff.

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sixstringsteve wrote:
I couldn't find any dealers with the CR250 T fitting for the radiator hoses. So this is an experiment. These fittings are for drip line. They say on them "for gardening only, not for hot water systems." So we'll see how that goes. They'll probably melt and leave me stranded in the middle of nowhere, and dissolve into my engine as well. I hope not, but we'll see. This is a temporary fix until I get the honda part.

Sounds like this didn't work out, since you were getting a new T later. You should be able to get a plastic heater hose tee for 5/8-in hose from any auto parts store for a couple bucks.[/quote]


It's working out, I've got about 4 hours on it. I'd just feel more comfortable with a metal fitting in there that is rated for the head it's going to see.

The problem with a 5/8" heater t-hose is that the KDX outlet tube is bigger than 5/8". I don't remember the sizes off hand, but it was next to impossible to find a T fitting that had an input the size of the kdx, and 2 outputs the size of the CR tubes. You can see how much bigger it is in this picture:




Does anyone know if the Honda t-fitting is bigger on one of the ends of the T?


The ONLY thing I don't like about how everything lined up is how the petcock valve has to be trimmed to clear one of the radiator tubes. I'm thinking of putting a valve in line with the hose that connects the tank to the carb, so I don't have to use pliers to turn the gas on.

I found a 2002 KDX 200 motor for $300, so I'm going to snag that tomorrow. Then I can rebuild it, do RB mods, and install it in the winter, and keep riding this motor in the mean time.

That sounds like a winning plan!

[/quote]
Does anyone know if the Honda t-fitting is bigger on one of the ends of the T?

[/quote]

Yes the inlet is larger than the 2 outlets on the Honda tee.

that may be just the ticket then.

sixstringsteve wrote:that may be just the ticket then.

yes that is correct.
been offline a while
Nice build! congrats