OK, I have decided to post pics, and keep a running report of this build. As you know, we are starting with a stock 2003 mint KFX 400. Since it is in good condition, we shouldn't have to worry as much about bearing replacements, and stuff being broken. So::
I rode this bike a complete day both in a race and fast trial riding to get a grip on how it handles, and it's power output:
My impression stock: kinda reminds me of a hopped up 300ex. It feels light on the trail, and is very quick handling. The power output insn't bad, but leaves alittle to be desired. All in all, I would rate this bike stock a "B"
Step 1: I will be using Houser components on this bike, so the long travel rear-end was the first order of business.
The build
Can you say "billet"
After tearing the rear end completely off the bike, it is now time to start greasing all of the bearings, and assessing the situation. Here is the 1 linkages side by side:
OK, now for the real part of this build-up. The rear-end was in stock at houser, as was the shock. So, after placing the order, I had the parts the next day (doesn't hurt to meet Jeff Houser for a trail ride and have them personally delivered).
After taking the stock apart, and pulling everything apart, I checked all the bearings and bushings that would be re-used. I cleaned them and re-packed with Bel-Ray waterproof grease.
Everything bolted right up, without a hitch. I will say that without the directions, it would have taken me alittle while longer, but all in all I would give the installation process a solid B+. The only downfall to this, I didn't take into consideration the swingarm being longer, and did not order the line to acompany it. But, the stocker is working, until later in the week. I did have to pull the muffler off, to run the shock res. line and also install the airbox lifter kit.
One thing to watch for is the needle bearings in the new parts, as they were not packed with grease, so when the little guys started messing with the parts on the floor, some of the needles fell out. Luckily all were found, cleaned and re-installed with lots of grease to hold them in place, until the factory sleeves were installed.
After taking the stock apart, and pulling everything apart, I checked all the bearings and bushings that would be re-used. I cleaned them and re-packed with Bel-Ray waterproof grease.
Everything bolted right up, without a hitch. I will say that without the directions, it would have taken me alittle while longer, but all in all I would give the installation process a solid B+. The only downfall to this, I didn't take into consideration the swingarm being longer, and did not order the line to acompany it. But, the stocker is working, until later in the week. I did have to pull the muffler off, to run the shock res. line and also install the airbox lifter kit.
One thing to watch for is the needle bearings in the new parts, as they were not packed with grease, so when the little guys started messing with the parts on the floor, some of the needles fell out. Luckily all were found, cleaned and re-installed with lots of grease to hold them in place, until the factory sleeves were installed.
The finished product, man you can tell a huge difference in ride height from stock.
My intitial test was through my small field, which has some choppy bumps, but nothing to extreme. You can really tell how underpowered this bike is now, the wheels felt like they were glued to the ground.
The shock feels alittle soft, so I'm hoping it doesn't have to be sent off for a revalve.
If you were to do this install, I would plan on a complete afternoon. I would say it took me between 3-4 hours to do. Of course when you have "little mechanics" helping, it always speeds up the process.
Here it is sitting on the floor after the initial ride.
My intitial test was through my small field, which has some choppy bumps, but nothing to extreme. You can really tell how underpowered this bike is now, the wheels felt like they were glued to the ground.
The shock feels alittle soft, so I'm hoping it doesn't have to be sent off for a revalve.
If you were to do this install, I would plan on a complete afternoon. I would say it took me between 3-4 hours to do. Of course when you have "little mechanics" helping, it always speeds up the process.
Here it is sitting on the floor after the initial ride.
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J. Delaney
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- Joined: Wed Mar 10, 2021 10:41 pm
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aroracer72
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- Joined: Wed Mar 10, 2021 10:41 pm
Motor wise, ive heard and been told to run stock cams, ports, valves, and rod....but use a yoshimura stroker crank kit with piston and use a good flowing pipe, this makes the best and most reliable race motor. When you install cams the head will go to poop after awhile, and the ports/valves and stuff are good stock.
CHAD
looks good keep it comin!!!...and those razr 2's on the back will kill the 400's power too....by alot..especially astock motor
CHAD
looks good keep it comin!!!...and those razr 2's on the back will kill the 400's power too....by alot..especially astock motor