Oil Change

Just bought a 2003 YZF 450 that was used in the racing circuit. Going through and checking all major areas, incl. doing an oil chg. When I pulled the plug, *very* black oil that smelled like it had gasoline in it, came out. I finished w/ the chg, and went to pull the dip-stick to check my levels, when oil came pouring out of the dip-stick holes. Any help w/ what may be going on here? How much oil goes into these 450? thanks.

This must be your first dry sump motorcycle, eh? It seems that you neglected to drain either the tank (contained in the frame) or the crankcase.

Wet sumps, like most Japanese bikes and your car, store their oil in the sump, in the crankcases, or in an oil pan. The oil pump picks it up, circulates it to the critical lube points, after which it drains back to the sump to start over.

Dry sump systems, like older Harleys (maybe current ones, I haven't paid attention) and English bikes, store oil separately from the engine. A feed pump draws oil from the reservoir through an external line, and circulates it as before. It drains back to the sump, also in the same way. But then, a second oil pump, the scavenge, or return pump, picks it up and returns it to the reservoir.

In operation, there is very little oil in the crankcase other than that actually lubing something. But when you shut the bike off, gravity continues to try to move oil into the crankcase. It slowly seeps past the unsealed oil pump shaft, and in anywhere between 3 days and two weeks, it will all be in the crankcase.

So, the correct procedure is briefly this. Start the bike and run it for about two minutes to circulate oil. Shut it off, and drain the tank. Then drain the crankcases. Now change out or clean the filter (if the element is cleanable). Reassemble the bike, and fill it. A 450 takes 1.2 liters total. If you change the filter, it will take about 1.1 to fill it. Without the filter, it's about 1.0.

Check out This Link for a more detailed look at the process. The page is for a 250F, but the process is exactly the same for the '03 year models.

The gasoline smell tells me it probably sat for a while with the gas on, or with a leaky petcock.

Do as he says, he aint talking analy, and remenber to change it often 5 / 6 hours

Hey grayracer;

I put some 20w-40 in my yz450 the last oil change, and once i filled the crankcase, the bike wouldnt start. Oil wouldnt even register on the dipstick. It took me quite a long time to get the thing to start.

Could this be because I put a little thicker oil in? Thats the only thing I did differently than the last oil change when it started w/ one kick.

In your 450, as in mine, you fill the system at the crankcase. The dipstick is located in the reservoir in the frame, a foot and a half away. Please tell me you were not surprised that oil didn't show on the dipstick until after it ran.

The starting problem was probably coincidental. The difference in cranking drag between 20w-40 and (I'll guess) 10w-40 is truly insignificant.

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