Need Mechanical Advise

[jlm400]

My bike started making some very loud noise in the valve train area so I pulled it apart and shimmed everything up to spec. It was BARLEY out of spec. Then is still made the noise. Then I thought I had a very bad tank of gas and it was knocking very loudy. Wierd so far to say the least. Then I shut my bike down and saw a large cloud of white smoke come out of the breather tube off of the top of the engine. Every time I kick the bike over it blows white smoke out of that tube.

Any thoughts??? Could it be rings? Or would a water pump seal be more likely?

[John_in_Long_Beach]

White smoke? or steam?

Just a thought but maybe it is a head gasket. If the water passages flow through the head gasket, then maybe water would flow into the combustion chamber.

But then you would see white smoke out the exhaust, and this isn't what you mentioned.

Just thinking outloud

[Taffy]

could be nothing. how does it run?

watch the water level very closely-has it dropped?

have you set your pilot screw?

is your hot start leaking-mine was. suck on the pipe to test.

when you drop your oil next look for a creamy white at the bottom of the oil.

good luck

Taffy

[Hick]

That IS weird.

I think water pump is a better guess than rings, although excess blow-by may result in a smoky crankcase (but that doesn’t explain the noise).

Picture this: counterbalancer bearing goes bad, shaft flops around, makes noise and in process ruins pump shaft and/or seal. Result is lots of noise and steam (and maybe burning antifreeze) out the breather. A quick way to check would be to yank pump cover and shaft and inspect shaft, seals and bearing. You may also be able to check for balancer shaft play through pump shaft hole with a small srewdriver.

This topic didn’t seem to be getting anywhere so I thought I’d take a guess…

But first I’d just check the oil and coolant for more clues. If you do let us know if you find anything.

[Matt_Porritt]

You'll know from the smell if its burnt antifreeze... cooked gylcol STINKS!! ?

But I doubt that you'll get it coming out the breather as the bike will burn it and spit steam etc out the exhaust if it was a headgasket.

Possibly you have too much oil in the bike or you didn't drain the g/box etc when you changed it?

I'd dump all the oil and check the volume and colour.

If white/grey and more of it then you have water probs.

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**Ride it like you Stole it!**

Matt Porritt

99 YZ400F

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