Thought Experiment: New Life to old and notoriously slow CR125

When I was a teenager and not willing to spend copious amounts of time tuning my bikes, my father bought me a spanking new 2001 CR125 for Christmas. Immediately, I was a little bit disappointed. Selfish right? Well my dad tried to buy me a YZ125 that day but, the Yamaha dealership was closed. The Honda dealership was open so I ended up with a slow and hard to jet CR125. I wanted to make it rideable but, at the time I wasn't too privy to much of anything. I was forced to carry a few plugs with me whenever I went further than a few feet from my tools. So, I have been thinking about picking up an 01 CR125 and experimenting with it. Adding some modern innovation and cutting and splicing to correct the known deficiencies. So here's some potential mods and tests I have been thinking about.

1.) Straighten the intake tract out and mold a newer, better, air boot. The CR125 intake manifold has a nasty hook in it to clear the shock. It is speculated that this one of the many reasons the CR125 makes such poor low end power. By shortening the intake tract and altering the position of the front of the motor, the angle of intake can be altered. A new air boot would need to be in order and one with much more volume and better air flow characteristic. Of course the shock is a limiting factor. Ever seen an air boot that wraps around a shock like a donut? Probably not....I wonder why? Maybe it doesn't work....maybe it does?

2.) Mirror the case volume and porting of a YZ125 a la Kawasaki. The KX125 got much better when they copied the YZ125...as did the CR125. The port layout on the 04' + CR125 is very YZ125esque.

3.) Swap to the Mikuni TMX 38 radial slide. The 36 TMX on the 01 CR125 was hard to jet and poorly jetted off the floor. A 38 radial slide would be a slight improvement in ease and a major improvement up top. Same carb as the 04'+ CR125.

4.) This would be challenging but, I'd like to see auxiliary exhaust ports (KTM, Suzi) controlled by the power valve added to the cylinder. New PV flaps would be required most certainly.

5.) Build a new pipe and ignition to mesh with the mods.

Of course, I'd need to do a lot of math to support my conjectures and there's plenty of other factors that go into it. All these mods could make matters worse. It's sure sounds like a fun experiment though and it would be neat to make some dyno runs and see how things worked out. I'll have to keep my eye out for a beater CR125.