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RR450 spitting oil thru gearbox breather

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why would the gearbox oil come out thru the breather that is beside the starter motor??
preassure must be building inside but i do not uderstand how it is happening.

any ideas??
 

 

gearbox breather.jpg

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That's your gearbox breather. It should have a hose attached.

Did you over fill your trans oil?

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no, when we took the oil out there was only 300cc in there. so at least half a

liter went out thru the breather. the hose is not there but it should make no 

difference. something is making the oil spill thru the breather. there is no way

that preassure from crankcase can fill the gearbox, right??

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You need a hose on that breather. It normally routes over your starter and then along the right side of the carb and ending at the linkage.

You could attach a clear catch bottle to the end of the hose, go for a ride and see if it fills.

Let us know what happens.

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Some 4 strokes have substantial case pressure, kx 450 is one.

Most 4 strokes have a larger outlet so pressure doesn't build and can escape quickly. That outlet looks rather small in comparison.

I would run a clear hose straight up to some where high under the tank, then loop it back down along one of the frame rails to the bottom of the bike.

If it's spitting oil with that set up....you probably have an issue.

Edited by moto9
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Some 4 strokes have substantial case pressure, kx 450 is one.

Most 4 strokes have a larger outlet so pressure doesn't build and can escape quickly. That outlet looks rather small in comparison.

I would run a clear hose straight up to some where high under the tank, then loop it back down along one of the frame rails to the bottom of the bike.

If it's spitting oil with that set up....you probably have an issue.

moto9, we are doing exactly that. running the hose upward with the clutch hose and cables then around the chassis and downwards.

hope this helps with the problem. but other 450 Betas that we have here without the hose don´t spit out the oil.

what i don´t get is why preassure from the engine side would go into the gearbox side. i might have a crack or bad sealing????

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moto9, we are doing exactly that. running the hose upward with the clutch hose and cables then around the chassis and downwards.

hope this helps with the problem. but other 450 Betas that we have here without the hose don´t spit out the oil.

what i don´t get is why preassure from the engine side would go into the gearbox side. i might have a crack or bad sealing????

You very well could, I had a simular issue with a cr 250.

Ok, First thing hook up a pressure gauge to the vent and take some readings at idle, 2000 rpms, 5000 rpms and wide open.

If you have another 450 there, compare your readings to the other bike....oil level in both bike need to about the same.

If you have a drastic difference in readings between the two bikes, I'd make a call to the Beta service dept and see if you can get an idea what might be the issue.

Could be a right side crank seal....just guessing.

You could also try to pressurize the gearbox side through the vent and see if you can hear air transfering, you'll need to make sure either the intake or exhaust valve are open first.

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