It’s a good thing we bought the owner’s manual with our remaining money, hopefully you did too, after a couple months thrashing on the little KX that could, it needed some serious attention. Pressurized coolant was leaking through the water pump shaft seal into the oil. The bike had no power thanks to a loose piston with cracks on the skirt. The KIPS power valve was so full of carbon it barely moved. And in order to shift into first gear with the bike stopped the motor had to be hot. These were the obvious problems. Are you getting the picture? Our KX was in need of serious attention.

For our first issue of 2008 we thought we’d go through the KX and give it the once over, maybe even replace a few parts that are giving us the shakes. If your bike is anything like ours, it is feeling a little loose in a lot of places. Our KX is really bad.

When we originally started this project we thought we’d just do what was needed to keep the KX ride-able, a new top end, fork seals, wheel bearings, and service the swing arm link, nothing major. With this in mind, we started with a call to All Balls Racing for some bearings. They make replacement bearings for the hubs, headset, fork seals and bushings, and everything you need to completely rebuild swing arm and linkage, including the oil seal for the rear shock. They even have crank bearings. We ordered everything they made for the KX.

Realizing how much effort was going to go into replacing all the bearings, our KX project took on a new life. We decided to go through it and completely rebuild it with all the aftermarket part we could find, there are many. Click HERE for a required tool list.

Starting with new crank bearings in hand we knew we would be splitting the cases, a call to our friends at Mac Tools was necessary for a universal case splitter. While we had them on the phone we also ordered a slide hammer, to pull bearings,

Motion Pro clutch basket holder and torque wrench adapter for those nuts that hold the cylinder on. We called on Wiseco for some top end parts and while talking with Al Pizzino, he informed us that they have complete bottom end kits, including crank, connecting rod and main bearing. Since we already had the main bearing from All Balls we ordered all the hard parts they have to fit the KX. Al was also kind enough to hook the KX up with a new clutch basket, the old one was toast. And a black anodized, billet clutch cover, these rate very high on the cool factor scale. We also ordered a piston kit, what motor rebuild would be complete without a Wiseco top end.

Underneath the clutch cover, Barnett clutch disks and plates will be handling the dissemination of power. Knowing that the KX was weak in the bottom end we called Boyesen Engineering for some help from their Rad valve, reed block. Boyesen also makes beautiful clutch and ignition covers, we opted for the black ignition cover and we are glad we did. The KX motor will go together with a gasket kit from Cometic. Dirt and debris will be removed from the air by passing through a No Toil air filter.

With our motor and rear shock out of the frame we thought it would be in our best interest to ask for help. Considering the amount of work we had with the rest of the bike waiting for us. Who better to ask for help than Chad Watts of Watts Perfections? In 1996 he wrenched for Supercross East #1 plate winner Mickael Pichon riding none other than a KX 125. In 1997 he began the era of the GOAT. The point is, he knows this motor inside out, upside down and sideways. Chad was kind enough to lend his skills to install the new connecting rod on the stock crank and rebuild the rear shock. The side play on the crank was way past the point of no return. The specified tolerance range is .40-.50, the service limit is .70 ours was .80.

Continued