2003 YZ450F Basket Case

[nellauaeb1327]

Hey guys just bough an 03 YZ450F for 500 bucks. Everything is apart but the motor, he never went into it. Basically what I have diagnosed is that he was burning oil and then fouled a plug. He though it was the timing chain but thats fine. Valves are great too. So basically ive ordered a new cylinder (plated) and wiseco top end kit. Bottom end is solid.

So what I was wondering is.

Whats the valve clearance for the bike?

Torque specs for the head and cylinder?

Ring Gap?

Oil Capacity?

Break in Oil?

Jetting (stock)?

and, is the bike really a beast like people say?

Thanks guys!

[DC_Excitement]

http://www.yamahaownershandbook.com.au/index.php yamaha is nice enough to offer free manuals. all 450s are beasts. a know of alot of people that bought them for first bikes and couldent handle it and moved down to a 250f. as for oil. your gonna get a million of different responces on here. me personally i run amsoil 10-40 for the complete life of the bike and always had good luck. get alittle pricey though

[rasta]

yes the 03's where known as drag or holeshot bikes. tons of bottom end. hardest hitting 450. wish still had mine. or a 03 motor in a aluminum frame

[grayracer513]

I had a killer '03 and an '06 at the same time, and I can tell you for a fact that no matter what it feels like, the '03 is NOT faster then an '06. Dead even through 3rd, but after that....

[nellauaeb1327]

I heard the power of the 03 is more snappy. Also, how long do valves usually last in the yz? THANK YOU FOR THE MANUAL!

[tech24]

I heard the power of the 03 is more snappy. Also, how long do valves usually last in the yz? THANK YOU FOR THE MANUAL!

Just short of forvever

[grayracer513]

I heard the power of the 03 is more snappy. Also, how long do valves usually last in the yz? THANK YOU FOR THE MANUAL!

It is more snappy. In fact, it's snappy to a fault. If it had 8-9 less horsepower, it would be a great 250 two-stroke, but it can be a bit of a handful to deal with as it is. It's clearly not as hard to manage as a CR500, but it is the most two-stroke-like four-stroke I can remember riding. The power reminds me of a '70 big-block Chevy, whereas the '06 is more like a 5.7L with the same power.

The valves in my '03 were still good at 350+ hours.

[nellauaeb1327]

Sounds like a fun bike! Cant wait to ride it! I have everything ordered and should have it together soon. I have a video to upload of it when I got it. Its apart, everything but the motor . Does anyone have pictures of their yz450. Or an videos?

[grayracer513]

Pictures?

https://www.thumpertalk.com/forum/showthread.php?t=932284

[nellauaeb1327]

here she is.

[Yamiryder]

Sounds good.?