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CRF450r Oil Dissapearing
04-22-2016, 11:15 PM
Post: #1
CRF450r Oil Dissapearing
Hey, I recently got myself a 2004 CRF450r and it's great fun. My first four stroke, whole different ride.

Was missing some bolts, patched it up quick. I ran the bike around the neighborhood, the oil in the sightglass dissapeared like it should. It came back down a few hours later, I did the same thing the next day, this time it didn't come back down? Now the spot around the sight glass, the crank case, has been bone dry. I did an oil change, and a nice amount still came out. Changed the filter too. Put the new stuff in and ran the bike. It dissapeared again so I just added more until I could see it in the glass. The bike doesn't smoke at all

It doesn't have any leaks, just a few drips and spits. When I do run it, It looks like oil gets blasted around the front sprocket and chain guide by the rear axle. It had a top end done about 6 months ago. Ive been calling a bunch of dealers, all around CA and NV, and I've heard everything from it's in the airbox, tranny, its burning, its in the fuel tank, etc. I've done the straight up and down thing. Can't seem to figure it out

Should I just run it, should I take it in? Where the hell is this oil going?
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04-23-2016, 10:15 PM
Post: #2
RE: CRF450r Oil Dissapearing
Did you talk to that guy? Or just those guys?

"250 is like the honey badger, it doesn't give a shit"

906+ years and still going!

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04-24-2016, 02:50 AM (This post was last modified: 04-24-2016 02:52 AM by Rev. That Guy.)
Post: #3
RE: CRF450r Oil Dissapearing
I tend to think that perhaps something is a miss here with the checking of the oil. Is is possible that perhaps the sight glass is simply full so you can not see the line of the oil? If so that could be a bad thing - too full. I realize this may sound stupid and I am certianly not trying to insult you in any way with this but you'd be surprised some of the things I hear as problems that turn out to be user error.

As far as excuses go from the dealers you have talked to, firstly, the motor shares oil with the transmission so the oil disappearing into the "tranny" is just plain stupid and no tech should have even mentioned this. That is something that I would actually call back and talk to the service manager about about because that guy probably shouldn't be working as a tech then.

As far as "In the airbox" - doubtful as there may be some in the airbox, but something else would be very wrong if there was a lot in there. Only way that would happen, and I am not sure on your particular bike if this would even be applicable, would be through the PCV valve, or Positive CrankCase Vent, usually found on dirtbikes coming from the top of the valve cover. I would have a hard time believing that any significant amount of oil would move that way. You can look by pulling your airbox lid and looking. There should also be a drain coming out of your airbox, usually from the lowest point of the airbox, with a small bottle or cap in it. pull the cap and see if you get anything out of that vent tube or nipple. If you get more than a few drips, you have problems that need to be sorted. You should get some or at least some residue as the PCV allows pressure to vent off and be captured by the airbox when the oil heats up and expands, but only in the form of an oil vapor that may condense back into liquid oil in the airbox. again, this should be minimal at best.

now when you say "blasted around the front sprocket" what exactly do you mean? You have a few things in that area that could leak oil - the output shaft seal, the shifter shaft seal and possibly the clutch arm actuator seal are about the only things that could leak, and by what you are describing in terms of missing oil, you would have a gooey mess and drips under the bike. The stuff you are seeing around the sprocket and chain area is likely chain lube that has slung off the chain and built up in that area.

it should never take a few hours for the oil level to normalize in the glass after shut down... this should only be a few seconds or minutes at most. That bike, I know, does not have an anti-drainback mechanism, or check valve if you will, so oil will drain back through the pump and into the case after shutdown so it may take a few minutes.

Worst case, I would suggest you drain the oil, fill it with the prescribed amount per the service manual or user manual and not pay attention to the sight glass. run it a few times and drain the oil back out, being sure to capture the oil so you can measure how much comes out. if it is about the same, you don't have any issues and just run it assuming you have no other indicators that damage is being done by a blockage that may prevent the oil from draining back (metallic noises or anything that seems off).

also make sure that you are using the correct procedure to measure through the sight glass as they all differ. Some say from the side stand, some from the center stand (on equipped bikes), some say while holding the bike vertical off the side stand. Perhaps that is the case is you are looking while on the side stand and the procedure calls for holding the bike vertically. This would cause you to not see the oil as it would be settling on the left side of the case if the bike was leaned on the side stand.

hope this helps.

- Justin

"You were taking it easy right? Because I could keep up with
you and from what I understand, I shouldn't be able to do that..."
- Ken "No Neck"

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