No oil on dip stick. 08 YZ450

Doing and oil change, and dropped the oil on the left side, and noticed that not much came out. Then dropped the oil on the right, and seemed to get most of the oil out. Didn't really think much of it. Filter looked clogged with black grit, and a little collapsed. I assumed that it was clutch. Plugged everything up, and put in 1L of oil. Checked dip stick, and there was no oil in at dip stick. Added 100ml of oil, no oil on dip stick. Checked oil filter, and oil in filter. Added 100ml of oil. Checked oil pressure screw, and found slow seep of oil. Checked dip stick, and oil just showed on stick. Dropped all the oil, and there was little on the left, and the rest on the right. Still very dirty.

Pulled the oil tank breather, and can blow to the left side. Can't blow to the clutch side.

How do you check oil passages, and oil flow?

when you put the oil in your bike you have to start it up and let it idle for a couple min then shut it off and wait 30 seconds then check the dipstick.

Idled for 4 min with no oil the first time, and up'd the revs a little. Idled for 1min to check the oil pressure screw. Something does not seem to be right....

I had the same problem on my 2008 yz450f i did everything and nothing would ever show up on the dip stick. Eventually it started showing up after about 15 oil changes. Now im doing a complete rebuild from the bottom up cause dirt got inside the motor and destroyed everything it still ran but blew more smoke than my cr250.

I had the same thing with my 2007 YZ450F and just had to rebuild the motor. That black grit is probably dirt and its stopping up your oil pump screen not letting oil pump through the motor you need to let someone open up the motor and check it out before more damage is done.

hmm wierd...

i have had my 07 yz450f sense it was new

i have never have had that problem...

how difficult is it to get to the oil pump screen? I don't see a pump screen on the drawing.

how difficult is it to get to the oil pump screen? I don't see a pump screen on the drawing.
To remove the screen, you have to split the cases. However, you can see it, clean it to some degree, and check the oil pump by removing both crankcase side covers.

First off, you have to understand how the oil system works. It's a Dry Sump system, which means oil is stored away from the crankcase itself in a separated volume. This is usually in a tank or in the frame tubing, but in yours, it's in the front of the engine. Note the shaded area in front of the engine on page 2-19 of your manual.

Oil flows, or should, through an internal passage to the pump. The pump is driven by an idler gear off the back of the clutch. Remove the clutch and rotate the oil pump gear counter clockwise. If there is oil in the feed reservoir (you may have to add it), it should pump in from the port in the pump body next to the gear. (You can also test this with the right crankcase cover still on the bike by removing the oil filter and watching for oil to be pushed up from the hole in the bottom of the filter well as you turn the engine over.)

To verify that the return pump is working, remove the left crankcase cover and watch for oil pumping from the port marked "from pump" in the picture below. (again, there does have to be a little oil in the sump for it to pump it) Looking through the opening in the lower rear corner of this chamber will let you see the oil pump screen.

It is also important that the external line that balances air pressure between the tank and crankcase is clear. With the dip stick out, and the filler cap off. you should be able to blow air through this hose in either direction.

Also, remember to remove the dip stick when draining, or it won't.

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hmm wierd...

i have had my 07 yz450f sense it was new

i have never have had that problem...

You probably have taken good care of your bike and never let dirt in the motor, I bought my bike used and the idiot who had it before me probably sank it or never cleaned the air filter because it had a good amount of dirt in it. Of course when I went to check the bike out the air filter was clean and it had fresh oil in it but the damage must of already been done. I got the bike for $3,000 and it cost me $1,300 to have a new crank and rod with bearings, a new piston and a new cylinder installed and the entire motor checked and cleaned so I have $4,300 in it now.

Thanks, I'll give it a try. Probably try doing a diesel wash on it to try to wash out the grim. Roll it over without the plug in, and flush like crazy. Then check the oil pump based on what you suggested. If that doesn't work, I'll start rippin'

It appears that this breather hose issue is the root of all my problems. Two times ago out, I filled the bike with water. Flushed all seemed well the next ride. Figured out the breather hose issue through the help of Thumper. Left the bike for a buddy on Sat, and he tried to kick in a mud hole. I'll probably take the valve cover off, and flush everything as well as I can.

You probably have taken good care of your bike and never let dirt in the motor, I bought my bike used and the idiot who had it before me probably sank it or never cleaned the air filter because it had a good amount of dirt in it. Of course when I went to check the bike out the air filter was clean and it had fresh oil in it but the damage must of already been done. I got the bike for $3,000 and it cost me $1,300 to have a new crank and rod with bearings, a new piston and a new cylinder installed and the entire motor checked and cleaned so I have $4,300 in it now.

i think its mostly cuz i change my oil way more than i should XD

It appears that this breather hose issue is the root of all my problems. Two times ago out, I filled the bike with water. Flushed all seemed well the next ride. Figured out the breather hose issue through the help of Thumper. Left the bike for a buddy on Sat, and he tried to kick in a mud hole. I'll probably take the valve cover off, and flush everything as well as I can.

filled the bike with water?? I assume by mistake

kicking it in mud hole will sux in all kinds of crud - it may take 3-5 oil/filter changes to get all the mess out. Marvel Mystery oil will help get all the water/condensation out. But if you have clogged a oil passage be prepared for a complete teardown.

Well not filled, I guess about 100-200ml of water. Pain in the ass to clear. 4 flushes. I hope a passage isn't blocked.

Not sure what the passages look like, but if you fill diesel through the filler, and then kick the bike over 15-20 times. I assume you will move oil up to the reservoir?? or will it drain back down faster than you can pump it up there? I'm trying to flush with diesel, and to clear the passages, and then with a couple to three litres of oil? Thoughts?

i have the same problem with my 2006 YZ450F. i havent had oil on the dip stick (i follow the owners' manual instructions) for 34 hours now. i am very meticulous with maintenance. this problem started after i rebuilt the engine. the oil pump went to pieces, destroying transmission gears, etcetera. i assume that the oil passages are blocked. now i have a new problem that just started. the engine crankcase vent hose is blowing a lot of oil out of the top of the engine. i will check passages etc to see what is going on.... tear down if necessary if no obvious obstructions.

anyone have an idea why the crankcase vent hose is blowing most of the engine oil out?

carypt

Had he same problem on my 03, you can clean the can clean the screen with out splitting the cases. Mine was caused by the discrentation of the clutch rubbers behind the cluthc gear. And here is how

I gaot mine and saved the race season and did not split the cases.

1. You have to take the entire clutch side apart and off the bike, and remove the oil pump.

2. Go to harbor Freight and get one of those cheap engine cleaning spray guns about $10, uses air and a suction hose to suck a solvent. Also go to the local hardware store and get on of the cheap drain cleaners called them " The Drain Claw " $6.00. and pick up a quart of paint thinner. This Drain claw is small and is flexable enough to get under the screen and you can work it back and forth between the case and the screen.

3. With the bike layed over a little so you can see into the case with a flashlight, thur the opening in the oil pump opening using the engine cleaner spray gun spray the paint thinner working it back and forth in the opening you can spray with pressure the paint thinner. And here is the hard part. If you see debris you have to fashion a small suction tube long and small enough to get into the case to vacunm up and debris that you see and trust me it will be all over the inside of the cases. I taped a 1/8" copper tube to my vacumn and it worked great. Also use the drain claw to clean the screen each time you do this. I did it about 10 times before i felt that i was not getting any more clutch rubber.

4. Check you clutch rubbers at this time. I also instaled a new oil pump and filter while it was apart.

5. Reassemble and fill with new oil. I also installed same clear hoses between the tank on the fram and the oil lines to the tank, so when I started the bike it could watch what was going on with the oil. Started the bike and all was as good as when I first bought it back in 03. i took it out for a practice day and changed the after 2 rides to get the solvent out of the oil. It takes time but t did work and I was able to ride all season with no issues.

Something that has been discovered since the original post was put up nearly 3 years ago is that the partition separating the oil "tank" from the magneto chamber is sometimes very thin in the area near the counter balancer weight on that side, while checking things according to my earlier post above with regard to the return passages through the cover, you should look for any kind of hole in that area. If one is present, it will drain off oil back to the sump before it gets to the correct level. The higher than normal sump oil level that would result from this will contribute to excessive oil being exhausted from the vent.

Also do an oil pressure check per the manual.

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