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Smoking and metal in oil after rebuild

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Bike is a 09 KX450F.

I did a rebuild including all new bearings and seals everywhere, new crank, new timing chain, new top end. 

 

After first start up I noticed some blue smoke when blipping the throttle. I may have assembled using a little to much oil on the cylinder was my first thought. 

 

After first ride the oil oil was changed, probably 2 hours ride time max and I noticed very fine non magnetic shavings around the oil filter. Rode the bike on the new oil and filter for 2 more hours, bike continued to smoke on throttle.

Did a 2nd oil and filter change now at 4 hours or so and I found more fine metal but was less than half the first time.

Made me think I snapped an oil ring when putting the piston on and was was going to break it down again but we went riding yesterday and I didn't see any smoke at all anymore and after we changed the filter for the third time now with close to 8 hours on the rebuild there was no metal in the oil.

Ive done a compression test and seem to top out at 105psi but don't have a leak down tester. Was thinking of running to harbor freight to get one but was wondering what you all thought?

I did the rebuild because the bike had 160 hours on the meter and was making a rattling, which was a broken transmission tooth. The cases were throughly cleaned and all the passages were cleaned. It's my sons bike and he bought it last summer with 130ish hours and the guy said the top end was done when the hour meter was added so it seemed excessive to me to let it go any further with out a full rebuild.

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105 psi with the auto-decompression is probably right. Seems that I remember the manual stating 90-106 psi for my '09 KX250F. If it's quit smoking and putting out any more debris, I'd ride it. The "non-magnetic" stuff sounds like clutch friction material more than anything.

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The metal is completely normal and so is the smoke after a rebuild. 

The metal comes from the parts wearing in and some metal comes off and ends up in the filter. Better there than anywhere else. Same thing would happen with a new bike.

Oil is normal as well from the assembly oil and the rings seating. 

Did you spec your valves?

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Thanks guys, your making me feel better. I did check all the valve clearances and double checked them after the first 2 hour ride. 

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Then you should be fine. Change your oil often until around 10-15 hours and you should have everything out and in good shape.

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first couple of hours needs to be regular dino oil. synthetic is gonna blow by the rings. some metal is ok, small metal flakes. you don't want to see bigger pieces obviously. compression seems about right with the auto decomp. If it has lots of power the motor is probably fine...

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7 hours ago, slothman said:

first couple of hours needs to be regular dino oil. synthetic is gonna blow by the rings. some metal is ok, small metal flakes. you don't want to see bigger pieces obviously. compression seems about right with the auto decomp. If it has lots of power the motor is probably fine...

No..... Again 

 

Edited by skorpan777

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20 hours ago, skorpan777 said:

No..... Again 

 

thanks for your valuable input. 

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