Frame drain plug on YZ 450 ?

It sure looks like a frame drain plug on the new YZ 450. It even looks higher than the aparent fill plug on the shifter side of engine case. Anyone know the details?

I was told that is the nitrous blow off valve.

I am pretty shure that the 450 is still dry sump. If it was wet sump, then they would brag about it, but all they said was "reduced oil capacity". I didn't think that yamaha would make the 450 wet sump since it didn't recomend wet sumping the 426.

I thought I had read they quit storing the oil in the frame and increased the crankcase capacity. But still not up to the original total capacity. Still dry sump. They say alot to get us to buy their equipment (it is their job). Do you think dry sumping is for improved control of lubrication or performance? Though without lubrication increased performance wont be the result LOL. They talk out of both sides of their mouth about performance issues because R1s & R6s have wet sump motors. Just a thought. Hard landings though I am sure cause momentary lubrication problems. :)

True about the R1's motor being dry sump but Ive also read not to get too good at wheelies because of oil starvation, dont know if that would affect a dirt bike though, but then again my R1 holds about 3 1/2 quarts of oil in the motor.


99 R1

01 YZ426

Norman your R1 has a wet sump engine as all streetbikes do. The oil starvation happens because of where the oil pickup is located in the sump and it would not happen if it were dry sump due to the constant pressure of oil entering the top end. just some info for you.

The R1 is a wet sump but your mistaken about all street bikes being wet sump.

tell me of a streetbike that has a dry sump engine please because I do not know of any. No sportbikes are dry sump.

I talked to the owner the dealership where I am getting my 450 that went to the Dealer show. He said they still have some oil in the frame and that is the fill plug. He said most of it is in the engine though.

Harley/Buell are dry sump but they are more lawn and garden equipment than street/sport bikes :):D:D


Sorry, typing mistake on the dry/wet sump, I know that, pretty funny about the Harley/Buell lawnmower thing though.


i dont see where it says its 'drysumped'

If you press the technical information button, and then the picture of the engine. Then scroll down to to the bottom of the page. You will find engine info:

Type Liquid cooled, 4-stroke,single cylinder, DOHC 5 valves

Displacement 449 cm3

Bore and Stroke 95.0 x 63.4 mm

Compression ratio 12.5:1

Max. Power N.A.

Max. Torque N.A.

Lubrication Dry sump

Fuel supply Carburettor (FCR39H)

Clutch type Wet, multiple disc

Ignition C.D.I.

Starting system Kick

Transmission Constant mesh, 4 speed

Final transmission Chain

Gear ratio 1 1.929

Gear ratio 2 1.563

Gear ratio 3 1.278

Gear ratio 4 1.05

Primary reduction ratio 2.818

Secundary reduction ratio 3.357

The '03 YZF's have the oil filler on the ignition cover, but the oil is still pumped up to the downtube reservoir for a dry sump motor.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now