Oil in the airbox??

[jkiserracing]

I noticed on my last ride that a good bit of oil came into the aibox from the vent hose that goes into it. Ive seen a little get in there before but this was much more than Ive seen normally. It was all over filter and all in airbox. Looks like my oil level is lower now (of course) than when I started riding for the day.
I keep my oil level at just under the "F" on the sight glass. That being...idle for aprox 5 min...then sit for about 3 to check the level.

Any thoughts on why this might have happened?

[blacknblue#2]

Blow-by more than likely...The top end is wore causing compression to blow past the rings which in pattern causes pressure in your crankcase causing oil to blow out of the breather tube..sometimes just rings will fix the problem...other times it can require rings and piston and jug.

[jkiserracing]

Well that don't sound good at all!! :eek2:

[DnB_racing]

this is the perfect time to do a leak down test, or at the bare minimum a starting compression .. with any luck you know exactly were your starting compression was set at for comparison,

but if you have a leak down tester this will without any doubts show you what you kneed to know, if it doesnt pass a leak down, get a stethoscope and listen for were its failing

or just do a topend if its been enough time it wouldnt hurt anyways ... how many hours on this one?

[jkiserracing]

Id say im at at least 25-30 hours on this one by now.

[DnB_racing]

Originally posted by jkiserracing
Id say im at at least 25-30 hours on this one by now. its time for a little work then...

not a big deal if you change now before any catastrophic damage is done it could be just a piston and rings...

actually just rings,like blacknblue mentioned, if you need to save a few dollars

but make sure you give that old piston and cylinder and rod end and wrist pin a THROUGH going over, use a magnifying lite and proper tools and if everything looks good you might get away cheap...

just for the record I always find something wrong or borderline. and end up changing the entire piston

if you do change the piston do a squish test prior to starting to see if any slight changes can be made to get just a little bit extra compression from it

[jkiserracing]

Ok.....looks like ive got a little work to do. I havent cranked it since that ride......however it did run awesome that day!!
Im gonna go ahead and check everything well......id rather not skimp on anything questionable to save a few bucks! Thanks for the info and advise.......i did not know the rings would do that. I'll let you know what i find out.

[Rich250RRacer]

One of the most common causes of oil in the airbox is a faulty relief valve. I've changed 5 or 6 of these already for people who have issues with oil in the airbox and this has fixed it nearly every time. Another cause is overfilling oil on the transmission side. DO NOT use the check screw to determine if the trans side is full when doing an oil change. Go by the factory spec in your owners manual, which is about 3/4 qt. If you try to use the check screw, you will overfill it every time.

[DnB_racing]

Originally posted by Rich250RRacer
One of the most common causes of oil in the airbox is a faulty relief valve. I've changed 5 or 6 of these already for people who have issues with oil in the airbox and this has fixed it nearly every time. Another cause is overfilling oil on the transmission side. DO NOT use the check screw to determine if the trans side is full when doing an oil change. Go by the factory spec in your owners manual, which is about 3/4 qt. If you try to use the check screw, you will overfill it every time. Rich, maybe im not getting the reasoning in this???but how does the transmission side being over filled affect the crankcase side?

im sure you know this ,but for those that dont....the breather that goes into air box is just the crankcase side, the transmission side has a separate breathe tube that loops under gas tank

but that's interesting about the pressure relief valve,Ill have to start checking those ...

Ive never had to change one, but cant they just be cleaned and blown out instead of replacing, I would imagine if found faulty it would be just plugged, from contaminated oil, and some degreaser and air would remedy the problem

and I would think if the relief valve was causing this, there would also be a problem with oil not being able to drain properly from the head. in other words a blocked drain hole as well? wouldn't the drains kinda act like a pressure release also,

from my understanding what the pressure relief is for is, if excess pressure from the oil pump to the topend, it will release the oil back into the crank, and not over pressurize the head and force oil into the valve seals, but wouldn't the returns have to be at least partially plugged for oil to be expelled through the top vent tube?

I would think a bad pressure relief would cause premature valve seal failure along with actual oil expulsion...
but there still would have to be some restriction in the returns

but I could be way off :D

[jkiserracing]

Originally posted by Rich250RRacer
One of the most common causes of oil in the airbox is a faulty relief valve. I've changed 5 or 6 of these already for people who have issues with oil in the airbox and this has fixed it nearly every time. Another cause is overfilling oil on the transmission side. DO NOT use the check screw to determine if the trans side is full when doing an oil change. Go by the factory spec in your owners manual, which is about 3/4 qt. If you try to use the check screw, you will overfill it every time.

Dnb..I have not got a chance to get into it yet but if I remember (i might be wrong) The vent tube for the transmission side may run up under the gast tank but I was thinking it connected with the crank case tube .....then went to the airbox.
I need to check all avenues on this it sounds like but.....coincidentally I did (accedently) way overfill my transmission side oil. I drained out the excess but I do in fact use the check screw on the motor. This overfill was done about 2-3 rides ago and I just now got all the oil in the airbox....that is if any of that was/is my problem.

[DnB_racing]

Originally posted by jkiserracing
Dnb..I have not got a chance to get into it yet but if I remember (i might be wrong) The vent tube for the transmission side may run up under the gast tank but I was thinking it connected with the crank case tube .....then went to the airbox.
I need to check all avenues on this it sounds like but.....coincidentally I did (accedently) way overfill my transmission side oil. I drained out the excess but I do in fact use the check screw on the motor. This overfill was done about 2-3 rides ago and I just now got all the oil in the airbox....that is if any of that was/is my problem. the hoses arnt supposed to be connected together, the lower crankcase and the hose from the head, T together and go to the air box

and the transmission is looped up on the right side and attaches to your heat shield to keep it from hitting the exhaust

unless you have a bad seal on your crankcase the transmission oil should never affect the crank side

[jkiserracing]

Originally posted by DnB_racing
the hoses arnt supposed to be connected together, the lower crankcase and the hose from the head, T together and go to the air box

Ah yes...that's right. I do remember that now. I knew something T'd into it.

[Rich250RRacer]

Originally posted by DnB_racing
Rich, maybe im not getting the reasoning in this???but how does the transmission side being over filled affect the crankcase side?

im sure you know this ,but for those that dont....the breather that goes into air box is just the crankcase side, the transmission side has a separate breathe tube that loops under gas tank

but that's interesting about the pressure relief valve,Ill have to start checking those ...

Ive never had to change one, but cant they just be cleaned and blown out instead of replacing, I would imagine if found faulty it would be just plugged, from contaminated oil, and some degreaser and air would remedy the problem

and I would think if the relief valve was causing this, there would also be a problem with oil not being able to drain properly from the head. in other words a blocked drain hole as well? wouldn't the drains kinda act like a pressure release also,

from my understanding what the pressure relief is for is, if excess pressure from the oil pump to the topend, it will release the oil back into the crank, and not over pressurize the head and force oil into the valve seals, but wouldn't the returns have to be at least partially plugged for oil to be expelled through the top vent tube?

I would think a bad pressure relief would cause premature valve seal failure along with actual oil expulsion...
but there still would have to be some restriction in the returns

but I could be way off :D

I ran across a thread on another forum (may have been on the org) about three years ago concerning strange oil issues on the 06-newer 450r's. The way I remember the thread, I believe the writer may have been a shop or engine builder. They were having the same issue with oil in the airbox, and after trying various things to fix it they were about to give up. They had the valve cover off the motor and were cranking it over by hand and they noticed an excessive amount of gurgling coming from the motor. as they continued cranking the motor, they claim oil was actually climbing up the cam chain tunnel. I don't remember how they decided on the relief valve, but they changed it and the problem went away. The very first one that came through my shop with the oil issue got a relief valve and the problem was fixed. As for the overfilling of the transmission, my personal theory is the excess oil, combined with pressure built up in the trans and a very small vent hose to relieve that pressure will allow oil to pass by the crank seal and into the crank side of the motor. I ran into a situation where a motor was pulling trans oil into the crank side where the owner had replaced the seal and the primary gear, and that still didn't solve the problem. The trans vent was clear but it was still getting trans oil in the crank side. Coincidently, the relief valve was also bad on this motor and it makes me wonder if the bad relief valve might also be creating enough pull to draw trans oil past the crank seal. Needless to say, these motors have some very strange traits, which is one reason I prefer the 04-05.

[QuadRacer041]

What is the preasure relief valve your refering too? Is that the reed valve looking thing that sandwiched between the cases under the crank?

[Rich250RRacer]

Small cylindrical piece in the stator cover of the 06-newer 450's. It's held in place by a circlip. 04-05's have one too, but it's in the center case, held in place by one of the center case bolts.

[QuadRacer041]

Originally posted by Rich250RRacer
Small cylindrical piece in the stator cover of the 06-newer 450's. It's held in place by a circlip. 04-05's have one too, but it's in the center case, held in place by one of the center case bolts.


I have taken these motors apart a bunch of times but have no idea where u mean. Is it in the stator cover or attached to the left case half?

[DnB_racing]

Originally posted by QuadRacer041
I have taken these motors apart a bunch of times but have no idea where u mean. Is it in the stator cover or attached to the left case half? Im guessing you missed where rich said they were located,

on the +06 its inside the stator cover held in with a circlip, on the 04/05 it inside the stator cover mounted on the left crankcase held in by a center case bolt...

im also guessing you dont have a manual,you really should get one, if just for torque specs and part tolerances... I reference mine all the time for any quad I work on just to check if parts are still in spec...

I wouldn't split a case without one, with the tight tolerances you really cant tell by eye if a parts worn out to the point of possible near failure

im sure if you googgle free manual something will come up, the link I had no longer works:(

[QuadRacer041]

Really, ive rebuilt these motors so many times, no manual no torque wrench.......i just use an impact gun on everything. motors seem to run fine. sometimes the center case bolts brake when i tighten them up but theres a handful of others left to do the job.:rolleyes:

[blacknblue#2]

Originally posted by QuadRacer041
Really, ive rebuilt these motors so many times, no manual no torque wrench.......i just use an impact gun on everything. motors seem to run fine. sometimes the center case bolts brake when i tighten them up but theres a handful of others left to do the job.:rolleyes:


If you have ever lost a crank or some other form of major failure that produces alot of shavings then the relief valve is a top priority to take apart and clean...heres a pic of what it consist of...Like the other guys said its behind the counter balncer on the flywheel side on 04/05 and below the filter on the stator cover on the 06+
http://i161.photobucket.com/albums/t207/aerospac/relief_valve.jpg

[DnB_racing]

Originally posted by QuadRacer041
Really, ive rebuilt these motors so many times, no manual no torque wrench.......i just use an impact gun on everything. motors seem to run fine. sometimes the center case bolts brake when i tighten them up but theres a handful of others left to do the job.:rolleyes: your missing my point of the manual, ya I could take apart and put together with my eyes closed also,
but to keep them in top performance with the extremely tight tolerances between high performance and poor performance its worth the money just for the specs...

I like to get every bit of power from them I can, and loose fitting or worn parts rob power and fail, and no ones eye can tell if something is worn .001 but it could be enough to cause a catastrophic failure if in the wrong place...

not to mention you would know were the pressure relief valve was located LOL

[QuadRacer041]

Originally posted by blacknblue#2
If you have ever lost a crank or some other form of major failure that produces alot of shavings then the relief valve is a top priority to take apart and clean...heres a pic of what it consist of...Like the other guys said its behind the counter balncer on the flywheel side on 04/05 and below the filter on the stator cover on the 06+
http://i161.photobucket.com/albums/t207/aerospac/relief_valve.jpg


Thank you for the info, wasn't sure if you meant it was behind the stator cover as in on the left case half or actually on the stator cover. I have an extra stator cover on the shelf and saw it. next oil change I think ill pull the cover and clean it out just to be safe.

[QuadRacer041]

Originally posted by DnB_racing
your missing my point of the manual, ya I could take apart and put together with my eyes closed also,
but to keep them in top performance with the extremely tight tolerances between high performance and poor performance its worth the money just for the specs...

I like to get every bit of power from them I can, and loose fitting or worn parts rob power and fail, and no ones eye can tell if something is worn .001 but it could be enough to cause a catastrophic failure if in the wrong place...

not to mention you would know were the pressure relief valve was located LOL


U make a lot of assumptions.

[DnB_racing]

Originally posted by QuadRacer041
U make a lot of assumptions. do you mean that Im wrong in assuming that you can take the motor apart with your eyes closed ,and that you could find the pressure relief with the book?LOL:huh

[brewster426]

Impact gun..torque wrench..same thing. Haha hopefully you are just kidding. Manuals save money and lots of confusion.

[2001400exrida]

Originally posted by Rich250RRacer
DO NOT use the check screw to determine if the trans side is full when doing an oil change. Go by the factory spec in your owners manual, which is about 3/4 qt. If you try to use the check screw, you will overfill it every time.

The manual spec says to use the check screw, i have always used it and have never had a problem. Also your 3/4 quart refers the 06 and newer trx's.

the 04/05 only calls for .57 qts in the tranny. I never measure, i use the check screw just like the manual states and have never had a problem with overfilling.

just my experience.

[Rich250RRacer]

Originally posted by 2001400exrida
The manual spec says to use the check screw, i have always used it and have never had a problem. Also your 3/4 quart refers the 06 and newer trx's.

the 04/05 only calls for .57 qts in the tranny. I never measure, i use the check screw just like the manual states and have never had a problem with overfilling.

just my experience.

I should have stated that more clearly. There is no issue with filling an 04-05 transmission and using the check bolt. This only pertains to the 06-newer engine because of where the oil goes first when poured into the engine. You would need to see the inside of a newer motor to fully understand why you should never use the check screw. You are correct on the capacity for each engine, the 04-05 will flow out of the check screw at about .57 qts., but an 06-newer will not flow out of the check screw until there's about a full quart in the trans, and that's if you pour it in slowly. If you try, you can get over a quart and a half in there before it comes out the check hole if you pour fast enough.

[jkiserracing]

Well I definitely use the the check screw and Id love to say thats all it was for me.......however....I did (in this case) see a drop in oil level in the sight glass....so my problem must lie elsewhere:confused:

[Rich250RRacer]

Originally posted by jkiserracing
Well I definitely use the the check screw and Id love to say thats all it was for me.......however....I did (in this case) see a drop in oil level in the sight glass....so my problem must lie elsewhere:confused:

You replaced the valve?

[jkiserracing]

Not yet.....will be getting into it tomorrow to find out exactly...Ill let you know