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blue smoke when revving in idle/nuteral

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I appreciate if you guys share your knowledge with me so i can underestand and fix my bike problem. 

i kick start my bike and there is no sign of blue smoke coming out. but when revving the bike in idle , sometimes i got blue smoke. 

i have no blue smoke when running the bike or in idle mode without revving.

my bike is 2011 yz450f , which have 112H on it and the piston changed on 90H by previous owner.

should i just order a complete piston and valve sealing kit and rebuild the engine !? or i just can go with it !? 

or ... !? 

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It means there is blow-by on the rings. Oil is burning in the combustion chamber and going out the exhaust. 

Check your rings and replace if they are out of spec.

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8 hours ago, LoLoSama said:

I would think piston rings (oil ring) starting to go bad.

should i just order them or change piston the same time !?

 

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3 hours ago, aminem said:

should i just order them or change piston the same time !?

 

Inspect them first. Unless the PO had receipts for it, you shouldn't always trust them. @ 90 hrs means it was done at 70. 

Inspect the pistons and I would plan on the rings.

My assumption is the rings didn't seat properly during break-in, so you will have to break them in again to have them seat. 

Inspect the cylinder and the bottom end when you have the engine open too.

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Yep, open and inspect before ordering anything, you'll save $ on parts and/Or shipping cost and time.

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1 hour ago, LoLoSama said:

Yep, open and inspect before ordering anything, you'll save $ on parts and/Or shipping cost and time.

tanx , i will go for an inspection before buying anything .

 

1 hour ago, MaybeMe said:

Inspect them first. Unless the PO had receipts for it, you shouldn't always trust them. @ 90 hrs means it was done at 70. 

Inspect the pistons and I would plan on the rings.

My assumption is the rings didn't seat properly during break-in, so you will have to break them in again to have them seat. 

Inspect the cylinder and the bottom end when you have the engine open too.

thank you for your comment , i shouldn't trust him :( . now i need to inspect and put money on this bike . is it ok that i am using the bike for now !? till i inspect and repair it !?

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8 minutes ago, aminem said:

tanx , i will go for an inspection before buying anything .

 

thank you for your comment , i shouldn't trust him :( . now i need to inspect and put money on this bike . is it ok that i am using the bike for now !? till i inspect and repair it !?

It should be okay as long as you keep an eye on the oil levels and make sure it is always full or close to full. 

Depending how bad it's burning, you could lose a significant amount quickly.

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Yep, should be fine, like Maybeme said just keep an eye on the oil level. I rode my previous bike (zzr 1200) for over 2 years and about 30k miles like that. When i took the engine apart, I had 2 cylinder that were letting a little oil pass. That was a time consuming job but the engine was a 4 cylinder so a lot more work. If you don't already have one get a OEM service manual, you will have a step by step on how to do that with all the specs. Make sure you follow it and take your time.

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On 8/3/2017 at 2:17 PM, MaybeMe said:

It should be okay as long as you keep an eye on the oil levels and make sure it is always full or close to full. 

Depending how bad it's burning, you could lose a significant amount quickly.

 

On 8/3/2017 at 2:28 PM, LoLoSama said:

Yep, should be fine, like Maybeme said just keep an eye on the oil level. I rode my previous bike (zzr 1200) for over 2 years and about 30k miles like that. When i took the engine apart, I had 2 cylinder that were letting a little oil pass. That was a time consuming job but the engine was a 4 cylinder so a lot more work. If you don't already have one get a OEM service manual, you will have a step by step on how to do that with all the specs. Make sure you follow it and take your time.

i just saw the oil level is at the top level , can it be the cause ( having more oil in engine !? ) i just remove the extra oil (around 100cc) .

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5 hours ago, aminem said:

 

i just saw the oil level is at the top level , can it be the cause ( having more oil in engine !? ) i just remove the extra oil (around 100cc) .

You need to download a factory service manual from Yamaha's website...

You check the oil on level ground 3+ min after running the engine.

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8 hours ago, THE KRAN said:

You need to download a factory service manual from Yamaha's website...

You check the oil on level ground 3+ min after running the engine.

tanx for suggestion, i have done it and my oil level that should be between A -B was above A(upper) i had remove some and when checking after 5min engine running its in the middle now 

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just wait and check the oil level , if you are not loosing power and no blue smoke when running , everything should be fine . 

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2 hours ago, aminem said:

tanx for suggestion, i have done it and my oil level that should be between A -B was above A(upper) i had remove some and when checking after 5min engine running its in the middle now 

Unless it is very far above, it won't make a difference. It could potentially cause it to blow smoke, but it would not hurt your engine. 

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Ride the bike, stop and let it idle, and see if it does it then.

Nearly every four stroke will puff some blue smoke when it's cold and you rev it.

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Just now, MaybeMe said:

Ride the bike, stop and let it idle, and see if it does it then.

Nearly every four stroke will puff some blue smoke when it's cold and you rev it.

What he said...

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Does it happen even after its warmed up. Or only when cold?

When cold . now it have no problem , i removed some extra oil from engine .

 

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Ride the bike, stop and let it idle, and see if it does it then.
Nearly every four stroke will puff some blue smoke when it's cold and you rev it.

Thanx, i didn't know that . I tried it + removing some extra oil i had on my engine (near 50-80 cc) . Now it look good . I just stop to rev it hard(rev limit) when i am in idel .
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Does it happen even after its warmed up. Or only when cold?

Do you have similar problem with your bike !?

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