Trans Oil in the Airbox?

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WildBill

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Mi. Trail Riders

Mar 29, 2002

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• Apr 14, 2003

• #1

Hey guys,

I have a question and I was unable to locate a thread on this topic that was posted quite a while ago. I have noticed oil pooling in the bottom of my airbox, and I cannot remember what the cause might be. The bike is a '90 KDX200. It runs strong, and is in really good shape. I am getting ready to do the top end, so I would like to address this problem as well. Any help is greatly appreciated.

Thanks,
Bill

 

Moteaux

Professional Mud Tester

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Aug 30, 2001

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• Apr 14, 2003

• #2

Wondering if it is excess oil from the air filter that has collected there after installing a freshly cleaned air filter. You do clean and oil it regularly don't you? ;)

 

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agitt73

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May 11, 2000

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• Apr 14, 2003

• #3

it can be two cycle oil or filter oil that has dripped out of your filter
when your bike is running some of the gas blows back towards the filter
and evaporates leaving extra oil in the filter

 

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WildBill

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Mi. Trail Riders

Mar 29, 2002

281

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• Apr 14, 2003

• Thread starter
• #4

Thanks fo the replies guys. I run a two stage foam filter with a filter skin and No-Toil filter oil. I believe that it is oil coming up through the tranny's vent tube and I remember a post that said it may be caused by a bad seal rom somewhere within. It is enough to form a puddle in the bottom of the airbox. If I had only printed and saved that post.

 

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23jayhawk

Sponsoring Member

Apr 30, 2002

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• Apr 14, 2003

• #5

If you never crash then maybe there is a concern. Seems like I usually find a small puddle in the bottom of the airbox, but I think it's getting churned out of the vent tube by the clutch when the bike keeps running after dropping it on the right side. A puddle, as in a shop rag soaks it all up - nothing really measurable collects there.

 

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WildBill

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Mi. Trail Riders

Mar 29, 2002

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• Apr 14, 2003

• Thread starter
• #6

Thanks, 23 Jayhawk. You have a good point. The next time I ride, I will have to try not to crash and see if it still happens. Wish me luck!

 

Canadian Dave

Super Power AssClown

Apr 28, 1999

1,202

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• Apr 14, 2003

• #7

Bill the only mechanical problems that come to mind would be a bad clutch side crank seal or a leak between the case halves. A bad seal on this side would allow oil to pass from the transmission to the crank case and be burnt during combustion as well as the transmission to become pressurized forcing oil out of the over flow. It would suck oil as the piston traveled up through the cylinder and the crank case is under vacuum and would pressurized the transmission as the piston traveled down through the cylinder pressuring the crank case. Signs that your burning transmission oil include excessive blue smoke out the exhaust, transmission oil level dropping.

Given the age of your KDX is would be a good idea to check the crank play and at least inspect the crank seals. If the clutch side seal is gone you'll burn transmission oil but likely not cause any damage. If the flywheel side seal is gone however extra air will be drawn into the engine causing it to run lean which can cause all sorts of problems including seized pistons, damaged cylinders, crank bearings etc etc.

 

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whtkdxtra

Member

May 23, 2000

72

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• Apr 14, 2003

• #8

I used to have this problem. I don't know what caused it but I can tell you what I did to fix it. I disconnected the vent line for the trans and blew the fluid out with air so the vent would do it's job, then reconnected it. I haven't had the problem come back. Give it a try.

 

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WildBill

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Mi. Trail Riders

Mar 29, 2002

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• Apr 14, 2003

• Thread starter
• #9

This site and it's members are great. Canadian Dave, what you mentioned is exactly what I was thinking about. The flywheel side is nice and clean with the gasket in excellant shape. I'll check the clutch side when I rebuild in a couple of weeks. Whtkdxtra, I'm gonna clean out / replace my vent lines as they are original. I am the third owner of the bike and it is all stock and mostly original equipment. I am not sure, but this may be it's first top end! It's in really good shape and I love this bike.

Thanks to everyone for the replies,

Bill

 

Jaybird

Apprentice Goon

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Mar 16, 2001

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Charlestown, IN

• Apr 14, 2003

• #10

I'll bet you a dime to a dozen Krispy Kremes it is excessive filter oil.
Try hanging your freshly oiled filter up overnight before you mount it. Just before you mount it, pat out the excess oil that is at the bottom part of the filter....the oil that would have been in the bottom of your airbox.
The problem will go away once you start practicing this.
:)

 

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snappy

Member

Apr 12, 2003

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• Apr 14, 2003

• #11

Could be that U overfilled your tranny.

 

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WildBill

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Mi. Trail Riders

Mar 29, 2002

281

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• Apr 15, 2003

• Thread starter
• #12

Thanks again for the replies guys.

What's Air Filter oil? Just kidding, a buddy of mine has a coworker that did not know to oil his air filter and this guy is a mechanic. Needless to say, he did a rebuild early in the bike's life.

I am confident that it is tranny oil and that I filled it to spec, unless the manual and case are marked incorrectly. I have only owned the bike for a year and the guy I bought it from only owned it a year and never rode it. As the third owner, I rebuilt the suspension last year with a top end on tap for this spring. The bike was basically 100% original when I bought it and I am unsure if it has ever been cracked open. It runs strong, as I ride with a '00 KDX220 and a '01 KTM 250EXC and we are all comparable, except the pumkin will get up and run.

I'm gonna check the seals, crankshaft play, clutch wear and vent tubes when I tear it down in a week or two. Hopefully, this will reveal the cause.