Oil Change YZ400F

How often do I need to change the oil on my '99 YZ400F.....? Actually I'm trail riding only on sundays for 4 or 5 consecutive hours, and what do I need to remove to drain the oil from the bike.....?

Well, since it's a 1999 model, and this is nearly 2002 and you're asking how to change it and how often, I'll assume you've never changed it before....SO...I'd say you should change it more often than you apparently are. :D:)

But seriously...my dad changes his about every 3 rides or races. Usually our rides are 3 hour or more MX practices (and we ride 95% of the time), and 2 hour hare scrambles. Figure every 8-10 hours MAX. Thats about how often I change my KTM.

I'm sure there is a post on oil changes somewhere using the search option...I'm not fully aware of how to change it on a Yamaha.

[ December 24, 2001: Message edited by: Chris Slade ]

Originally posted by humbertob:

How often do I need to change the oil on my '99 YZ400F.....? Actually I'm trail riding only on sundays for 4 or 5 consecutive hours, and what do I need to remove to drain the oil from the bike.....?

First thing, go buy an owners manual. It will show how to properly do it.

The more you change the longer the bike will last. With 5 hour rides, should change after each ride, no less than two rides. I chgange after three races = 1 hour per race = 3 hours per change.

If you haven't yet, you should change your oil filter. Then clean this with contact cleaner every three oil changes.

BE CAREFUL!!!!! when you change the oil filter, make sure you bleed your oil line. Did I mention you should purchase an owners manual?

If you have a stock pipe, you must loosen your header pipe to change your oil filter.

How much oil you put in depends if you changed/cleaned your oil filter.

Go purchase your owners manual and good luck. Remember this oil cirulates thru the motor as well as the clutch, it must me clean.

With preventive maintenence this bike will last a long time = enjoyment all round.

Go moto.

I've read some of Humbertob's other posts. He has just purchased this bike used which explains why he hasn't changed his oil yet. I was in the same boat as I purchase my 98 used (without the book) too. I can tell you this Humberto, definitely change your oil. No telling when it was done last. When I did mine I could instantly tell a difference in the way the clutch behaved. I also found some metal shavings in the filter. Not terrible but concerning to say the least. You'll want to check the filter too. It resides under a cover (2.5 inches in diameter or so) on the right side of the motor. It's held in place by two hexhead screws (top) and one allenhead fastner (bottom). Be sure to position a drain pan under the motor when you remove it. If the filter's not in too bad of shape, it can be cleaned and reused. I changed mine due to the metal shavings I found. The drain plug is on the main frame spar at the bottom.

There is also (apparently) a screen just below that, that needs to be cleaned but I hadn't seen that post prior to changing my oil so I missed it. Next time I'll pull it too. If I had shavings in the filter I'm sure there will be something caught in the screen as well.

Any tips on this part guys, would be appreciated. Like I said I haven't gotten my book yet.

I'll definitely be buying a shop manual. Part of the fun for me, is to work on things mechanical.

[ December 25, 2001: Message edited by: Rusty ]

The screen in the frame is not as fine as the regular filter. From reading these posts it sounds like it's there mainly to trap large particles such as paint chips, etc. when the bike was new. I too recently bought a used 99-400f and didn't really worry about cleaning that filter. it sounds like most don't bother after a few cleanings. Of course a check of it isn't a bad idea since you really don't KNOW the history of the bike. I plan to check mine next time also. The manual says it takes ~60-70lbs (if I remember) of torque to get the bolt off, so expect a challenge.

As Marion said, get a manual! After you change and/or clean the main filter, you need to loosen the oil supply line to the back of the motor. This is so that when you start the bike, you know it's getting oil. It's little things like this that make the manual worth it's price! Oil changes aren't difficult, but there are 4 or 5 steps you need to do. It's not just draining the oil and cleaning a filter...but how much really is that easy?


I'm still looking for the manual...You should be good for 100 between oil changes, unless you do really tight trail riding, where the oil gets fried...

I'm waiting for the Salsa... :)

Hey Jamracing, I'm so happy to see you post here too ! If you find the manual please send it ASAP I'll pay for it if you want ! The Salsa is already on it's way to Winter Park, FL. it should arrive shortly !

May you tell me where's the drain plug on the YZ400F, and please remove the YZ400F from your signature, remember that this beauty is now mine, Jajajaja ! :)

Humberto - oil change tips:

(1) There are three drain plugs, the frame behind the front fender (17 ft/lbs torque), the engine case (under the skidplate, 14 ft/lbs torque), and the oil filter housing allen bolt by the exhaust pipe header (7.2 ft/lbs torque).

(2) Take out and clean/inspect the oil filter with every change (the other two bolts use the same torque spec).

(3) Change your oil OFTEN! I change mine every ride (or every other depending on how long I rode).

(4) Use a cut up milk carton or something to block the oil from hitting your front tire when draining from the frame. The oil come out under a little bit of pressure.

(5) I think your bike requires you to loosen the header to get to the oil filter unless you have an aftermarket pipe.

(6) Don't trust the dipstick unless you start and run the bike for a few minutes then pull it out, wipe it, push it back in (don't screw it) within about 30 seconds of running. I just measure out 1600 cc and pour it in in my 2001. I am not sure if your's has the same capacity. Ask around. Be careful with the last 100 cc or so. Pour it slowly. The bikes have a tendency to choke on that last little bit and will overflow all over everything if you are not real slow...

This should get you started. Get a new drain plug for the engine from your dealer and ALWAYS use a torque wrench.

Steve T

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