Faults:

Cooling impeller was worn when I got it, engine oil and coolant mix.

Metal pipe to the water pump had a "hair crack" and was losing water.

Electric generator was impossible to take out; damaged the crankshaft while trying (finally got it out).

General Comments:

An excellent 4t enduro.

Dual camshafts and 5 titanium valves. 5 gears. Low cost and easy maintenance. Can handle a great deal of punishment from amateur or young riders.

Problems:

The water pump impeller shaft gets worn out after 200 hours. Replace it, along with seals and bearing.

The valves are made out of titanium and are very expensive (all 5 of them). You can cheaply replace them with steel ones from the YZF 400, but you will need to replace the springs as well (heavier valves need stronger springs).

Valve clearance needs to be checked often (every 30 hours), because they are very expensive and go bust without much warning. You will know that the time has come, when cold starting gets a bit more difficult.

Oil needs to be changed every 20 hours in fun/weekend/trail ride mode.

5th gear and 2nd gear shifting arm gets easily worn, and needs an engine tear down to fix.

The seating position is a bit high, but it is good for handling.

Not much else is needed. Just add gasoline and ride, but just remember to change the oil and check the valves.

Must upgrade:

At least the exhaust camshaft to an automatic one (Hot Cams or from an OEM 450 model). Makes starting much, much easier.

Exhaust (really anything is better, but the FMF system I had was excellent and quiet).

Should do:

Lower the final drive gears to 14/52 (from 14/48 original). You lose some top speed (will pull about 130Km/h), but the bike will be able to handle any terrain, and you can wheelie even in 5th gear with no effort.

Upgrade camshafts with Hot Cams and valve springs with Kibblewhite kit.

Change the rear fender. It is ugly. Use a stock YZF fender with some LED lights.

Change the rear spring with a harder one. OEM gets easily soft.

Hold tight. The bike tends to wheelie rather than slide (provided you have good suspension) even in wet grass.

Faults:

2001 WR426F Supermoto.

Chain slider wears through very fast (this is due to the different wheels and sprockets size though, as it's a MX bike that's been converted to a road going supermoto!!)

General Comments:

Totally awesome, fantastic fun, it's a 426cc single, bags of power. It's a motorcross bike that's been converted for road use / track use. If you're getting out of sports bikes like me, these are GREAT fun.

The top speed of 99 mph is about as much as it will do, but it's a scream through the twisties, will wheelie in 1st, 2nd and 3rd with no clutch at all; it's a loon bike.

It's got the following upgrades:

Talon front and rear sprockets.

Gold Talon hubs, Morad rims, "Braking" caliper / disk, FMF exhaust system with Power Bomb, gas flowed head.

Smaller rear light, Renthal bars, Tag triple clamps, shortened and stiffened suspension (front and rear).

Ohlins rear shock, Pro Circuit graphics, Heavy Duty O-ring chain.

Carbon guards: Sump skid plate, kick plates, swing arm, frame, stone guards, sprocket covers, chain guides, numberplate...

Trialtec digital speedo, and Alien headlight conversion.

Great fun on and off road!

Steve.