Amount of oil in engine?

11 replies to this topic
  • 2fastwhitey

Posted March 10, 2006 - 07:14 PM


When I change my oil, I've noticed there is not very much oil in the engine case. I haven't been able to understand how the oil system works on the 00 426 because there is no info on it in the Cliymer manual, so any info there would be great.

Basically what I am noticing is that there is only about .3 - .4 Litres in the case(engine drain) and about 1.0-1.2 L in the frame when changing the oil. Anybody ever notice this or know anything about it??

I would think that their would be need to be more in the case but that really depends on how it is circulated through the engine. It might not be as big of deal as I am making it but I have to know.


  • shanedut

Posted March 10, 2006 - 08:10 PM


The case and the frame drain plug are not seperated the oil circulates through the cases and the oil resevoir. If you ever tried checking your oil after your bike has sat for a few weeks, you will not see any oil on the dipstick or very little. The oil drained into the case from the resevoir. You have to start it up get it good and warmed up then check the oil. It doesnt have 2 seperate oil systems like hondas and other bikes do.

  • grayracer513

Posted March 10, 2006 - 11:49 PM


Your bike is a "dry sump" oiling system, as opposed to the far more common "wet sump".

In a wet sump. oil is stored in a sump at a low point in the engine assembly. There is one oil pump, which picks up the oil from the sump, and pumps to all the important places, after which it drains back to the sump and waits to do it again.

In a dry sump, oil is stored in a reservoir that is isolated from the actual crankcase. This can be anywhere on the bike. On yours it's in the frame. On the '06 and later 450, it's built into the engine, but it's still a separate volume. There are two oil pumps, the first of which is the feed pump. This takes oil from the reservoir, circulates it the same as the wet sump system, after which it drains back in the same way. But once it hits the crankcase floor, it is picked up by the second pump, called the return, or scavenging pump, and sent back to the reservoir.

Dry sumps were, at one time, the standard among the more serious four-strokes, and they still have several technical advantages. Dry sump systems can carry any amount of oil the designer chooses to allow for without making the engine big and bulky to hold the supply. Because of that, the engine can usually be mounted lower. Dry sump tanks can be designed in such a way that they will feed oil at almost any remotely upright angle, too, so concerns about oil sloshing away from the pickup screen are reduced.

When your bike has just been run for a time, there will be very little oil in the crankcases themselves. As it sits, however, the oil will try to leak back into the crankcase. There is a check valve to prevent this, but it is in the circuit downstream from the oil pump, which has no seals on it. Oil will eventually sneak past it, and if your bike sits long enough, the tank will empty into the engine.

That's why it's important to run the bike for about 1 1/2 minutes at least before you shutdown to check the oil. And the oil capacity of a 426 is 1.6 qts with a filter change, 1.5 without, 1.7 total in the system. Don't exceed 1.9 qts, or it will be unable to completely scavenge the sump. The result will be an oily, smoky mess, although nothing will break.

  • 2fastwhitey

Posted March 11, 2006 - 12:42 PM


Thanks grayracer.... I am fimilar with the workings of a dry sump system, my dad had a Lamborghini Miura and that was the only car that we have ever had with a dry sump system on it.
I was leaning toward the dry sump side but their is really no diagram or mark-up in the Clymer manual. I also haven't seen a return line for the oil in the frame. How is it circulated back to the tank?

  • Matt96xr6

Posted March 11, 2006 - 12:46 PM


Not again.

Look at the bottom of the frame down tube. There is a soft into hard oil lines that feed the motor from the oil reservior. You have to remove the oil line from the bottom of the down tube from time to time to clean out the filter screen there on top of changing the filter.

  • grayracer513

Posted March 11, 2006 - 03:06 PM


The return line on the '00-'02 models starts from the left side of the crankcase in behind the shifter, and runs up the left side of the frame to a point behind the steering head.

On '03-'05 models, the return pipe is run up inside the frame tube, so the line starts at the same place on the engine, but ends at the base of the main down tube, next to the feed line.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • 2fastwhitey

Posted March 12, 2006 - 07:38 PM


Yup, I was just out in the garage and sure sh*t I found it. Thanx

I also noticed what you said, I checked the oil after the bike had been sitting and sure enough the oil had drained back into the case. I appreciate the info, anybody know of a better manual for the 00 426. I didn't have any problems with it thus far but it really doesn't show how things work, just gives a brief break down of how to do

Thanks Grayracer

Matt, I knew about the screen at the bottom of the frame, and it comes out clean with no shavings or debris. Thanx

  • grayracer513

Posted March 13, 2006 - 10:14 AM


The OEM manuals are better than the Clymer, but in over 30 years as a professional in the trade, one thing I have yet to see is a shop manual that does a decent job of explaining the operation of the machine, or the reasons behind some of the recommendations, and Yamaha's Owner Service Manuals are no exception. IMO, understanding how something works is far more valuable than a troubleshooting chart, and knowing why you should or shouldn't do something makes it stick in your head better. But, it's just something you don't find that often, unfortunately.

  • SureBlue

Posted March 13, 2006 - 10:33 AM


You can find a downloadable pdf-manual, unfortunately non-printable from

then click: support - view owner's handbook
then select the cathegory of product: motorcycle
then enter model name: 426
then search (no need to choose year)
and you will get manuals for 5 different 426's.

Just download the manual you need and at least you have a readable manual.
Lots of other manuals too :thumbsup:

  • Motox520

Posted October 29, 2007 - 09:07 AM


just a quick question... a friend of mine has a 2004 450, the front down tube came out and he lost all the oil. The bike seemed to have automatically shut down. We brought it back to camp, found another bolt and refilled the bike with new oil. Started it and it seems fine, runs perfect, no noises. My question is, do the Yamahas have an automatic shutdown feature in the case you run too low on oil?

  • grayracer513

Posted October 29, 2007 - 09:45 AM


just a quick question... a friend of mine has a 2004 450, the front down tube came out and he lost all the oil. The bike seemed to have automatically shut down. We brought it back to camp, found another bolt and refilled the bike with new oil. Started it and it seems fine, runs perfect, no noises. My question is, do the Yamahas have an automatic shutdown feature in the case you run too low on oil?

No, they don't. That means...:worthy:

However, if it really does run OK, then there is a very small chance that you could have dodged a bullet. It would be the most prudent thing to tear it down and inspect it, because it could be damaged to a small degree, and the damage may be such that it will deteriorate rapidly from this point, possibly with expensive consequences. You decide.

  • Motox520

Posted October 30, 2007 - 12:01 PM


ok, just ran it on the stand for a couple 3 minutes or so last nite, sounds perfect, nice and snappy n crisp. Then drained the oil, watching for anything abnormal to come out, also checked the filters, no metal, no nothing, just the brand new oil came. I wasn't with the guy when he lost the oil, all I heard was him saying he shut it off cuz it blew up. I think he "thought" it blew up when he saw all the oil overwhere. I am thinking of buying it for my kid. It's only been rode 5 times. And get this, the guy told me he had a dealer do the first oil change on it... so I know how the drain bolt fell out now. Same dealer that tuned the bike for him also, come to find out it wouldn't hardly run when he got it back cuz the fuel screw was turned all the way in till it stopped!!

Related Content


James Stewart back on a YZ450F by YamaLink

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  47 replies

Wilson the Blue Privateer by jetfuel

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  50 replies

Megabomb Fitment by 288yz450

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 1 reply

BIGBORE FOR YZ450F 2006? by Taattie94

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 5 replies

2016 YZ450 by CaptainKnobby

Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  59 replies

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.