older 4 stroke bike help...

6 replies to this topic
  • skidoome

Posted March 23, 2002 - 05:12 AM


I know its not a new bike but I have an 550xt and it spits oil out the crankcase vent tube. Is this normal? It soaked the airfilter really bad. I cleaned up the tube and aircleaner and it was still spitting oil through the tube when I was running it. Does anyone know why a 4 stroke would spit oil through the vent tube?
thanks for the help...

  • John_Lorenz

Posted March 23, 2002 - 05:24 AM


Thats a major problem
its called fourstockalipus, it is contagious I would not ride it for a week and buy all maeans man keep it away from the younger Four strocks

:) Seriously though, If the beast is spitting oil could mean a few things
1: To much oil is in the Crankcase (Over Filed)
2: The Oil system is plugged or becoming plugged (AKA Filter needs Replac)
3: A pinched oil tube causing it to backup pressurise

I would start with changing the oil making sure the filter is new, also that the pump is not dirty stuck or in need of repair. I would also look to see if there are any pinches / bends / breaks in the oil delivery system.

I would not ride it until you discover why the oil. It could be as simple as an over filled Crank case

  • skidoome

Posted March 23, 2002 - 05:31 AM


Thanks for the quick reply... When I get home I will change the oil and clean out the case and try to find the problem. The bike has sit for 5-6 months because I am busy riding my snowmobile and going to college. I just wanted to ride it over spring break and the problems started... Someone else said maybe the oil system leaked into the case causeing this problem... is this reasonable? Thanks for the replys

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  • John_Lorenz

Posted March 23, 2002 - 05:41 AM


Ya that could be, If the bike has sat for awhile, Ya then you really should drain and maintain the oil, gas and so on. For a suggestion next time you need to stor the bike do the following
1: Drain GAS Tank / CARB place about 1 -2 oz of 2 strk premix oil in the tank and slosh it around to coat everything
2: Set the bike up off the ground both tires elevated
3: Oil Drain is a mixed question But I will usually drain about half just to keep the some in

But any way go through the bike it could be that oil seeped that indicates a oil leak inside the case bad seal or just dumb luck I dunno.

:) Sorry really make sure the Oil system is not plugged, Oil if sitting or is real old can gum up

[ March 23, 2002: Message edited by: EgoAhole ]

  • skidoome

Posted March 23, 2002 - 05:59 AM


Thanks for the advice... when i get a chance i will tear into it and hopefully find what is causeing this ... thanks

  • Chaindrive

Posted March 23, 2002 - 02:24 PM


I ain't no "bike mechanic" but 4-stroke internal combustion engines will blow crankcase oil out their breathers when ring seal is deteriorated :) oes it burn oil & smoke too? old bike? worn rings? Did it sit a long time? Pitted cylinder? A 62 year old "wheelie King" friend had a similar problem when he did wheelies longer than a block or two on his Kaw "dual sport" (seriously). He wrote to Cycle World magazine and they did a very funny cartoon along w/response. Advised him to run the longest breather hose he could, LOOPING it in circle and ending it as high as possible.Cheap cure for an old bike?

  • skidoome

Posted March 24, 2002 - 04:35 AM


It is an older bike but has been running like a champ. Well 6 months ago. It has been sitting for at least 6 months and just started to spit oil out the breather into the airbox. I don't think that it is the rings but thanks for the reply. I will know more when i get into the engine.


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