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Bike is SMOKING BAD!! PLEASE HELP

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I recently tore my bike down, sent my head off to get ported, rehoned the cylinder with a dingle ball hone #360 grit, and put it all back together with a new JE high comp. piston from Pro Circuit, new rings, and new gaskets. I put it all back together and went down to my track to ride. My oil level was 1/3 way up on the stick cold and after riding 10 minutes after seeing how bad it was smoking I decided to go back to the house to check oil level. It was barely on the low mark. I filled it to where it was 3/4 way up on the stick, went and rode for 15 minutes, come back add more oil and keep repeating to get a total of about 1 hour of ride time in. I am an Intermediate level rider and I was breaking it in per MotoMan's method (hard). I then went to a race and it was still smoking bad in practice but during the race it seemed that it wouldn't smoke as bad but every once in a while it would poof out a cloud and when I checked my oil after the race it had only gone down 1/4 stick. I decided to tear it down and rehone the cylinder, put new rings, and intake seals in and assemble it dry. When I tore it down there was oil sitting on top of the piston and the spark plug was gunked up with crud from oil burning in the combustion chamber. I brake cleened the comb. chamber and exhaust ports to get oily crud off and assembled it indexing the rings the way the Honda manual says to do it. I kicked it over slowly with thumb on kill switch about 60 times, added oil, went and rode and it still doing the same thing. I routed the crankcase breather tube into the atmosphere and saw no difference. My bike sputters because of all the oil that is being burnt and my exhaust pipe is full of oily crud. This is not normal break in smoke, there is definately something wrong and I have run out of logical things to do to fix it and don't want to take it to a shop. This thing is really pissing me off :thumbsup:.I would appreciate it very much if you have any suggestions to fix the problem.

Nate

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I recently rebuilt my bike. my mechanic told me to put a small amount of oil in the cylinder dont do it dry. But not a lot of oil or it will glaze over and not seat properly. I dont know why your bikes puffs so much you would think its because the rings wouldnt seat but if uve tried a few methods i dont know what is up. And it puffs really bad. What is your piston ring end gap? It will always puff a little bit of smoke when cold but when it warms up it should go away completely. if it smokes when its cold its not that uncommon but a lot seems funny. When u assembled it dry it should have been perfectly clean. It also could have soemthing to do with your new stuff...actually one sec....with your new hc piston u will have to go larger on the pilot, needle and main jet. Also u will have to run a higher octane gasoline. Strip your bike down again. hone the cylinder, get some new hp4 gas. new rings.assemble their end gaps on seperate areas as your manual says. put it back together with a tiny bit of oil in the cylinder. You should have changed the valve springs as well if u didnt. That would be the most important thing but i doubt it has anything to do with your oil burining. put it back together. warm it up completely. Go for a 20 min ride. fairly hard. let it cool down completely. warm it up again and go for a ride. With my new rebuilt i had to be burnt and it took a little while. After the first 20 mins the rings should be mostly seated and give it another go. If its not fixed then i dont know. I rebuilt my bike and my method worked really good. Other than that i have no idea. maybe send a pm to a guy named burned or kelstr they are really smart dudes. Other than that give it a go. Cheers throw a new plug in it too. best of luck.

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As a qualified engine tech with 30 yrs experience and having read what you did the only thing that jumped straight out at me was the honing of the bore. particularly as you had the smoke problem straight away. these are plated liners and that plating is quite thin, a quick scuff is all that is required just to de glaze if you went at it hard with power tools you may have taken the coating off the barrell. hope this helps and good luck

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I had a machinest do a light power hone before the dingle ball hone. Is the nikasil that thin? I would think that if it was that thin you would have to buy a new cylinder every time you put a new top end in.

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After I ran it the first time and tore it down, I could still see the hone marks and everything looked cherry so I dought that that could be the problem.

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OK. what we have to do here i believe is look for the clues. we know you didnt have a smoking problem prior to rebuild and immediately afterwards you did. thus we must correctly assume the fault you now have is as a result of something you did or that occured during the repair. you have used quality parts and the same run in as most of us. so its unlikely to be bad parts or poor run in. that amount of oil you mentioned above the piston could really only occur if you forgot to put the valve seals in or you have large amounts of oil getting past the rings. the nikasil is only a few thou thick it is an electro plating process. if the machine shop used a cutting tool to clean the bore, that is anything other than a fine grade flap wheel then i personally think that is when the damage was done. if we think logically it cant be anything else

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If you are totally confident about the bore being ok the only other thing i can think of is some error when you have had the head ported it may be thin or porous somewhere and the porting has cut into a weak area or there could be a hairline crack if guides were pressed in but do double check all the valve seals first as that much oil on the piston top suggests a downward ingestion

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Check your piston to cylinder wall clearance, if it's too large (over .0008 to .0015) you'll never get it to seal.

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Check the expander ring, under the oil rings, for a broken or overlapped tab.

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I thought the top end was supposed to be assembled dry, without oil on the cylinder or piston. The rings can't seat with even a light coating of oil. Check with Kestlr.

Just a guess.

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Check your piston to cylinder wall clearance, if it's too large (over .0008 to .0015) you'll never get it to seal.

BINGO!

The only way to be sure about the coating is to measure the piston to wall clearance and the ring end gap. Have a machine shop check these to make sure they are in spec with the service manual.

A wise man once told me, he who is not careful with the hone will quckly turn his 250 into a 450!

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I really appreciate all the info guys :thumbsup:.Do you know what the optimum range should be for the piston to cylinder wall clearance?

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According to the service manual for my 05:

maximum cylinder size 78.04mm

minimum piston size (measured front to rear, 7mm from the bottom) 77.89mm

maximum piston to wall clearance 0.18mm

top ring end gap 0.44mm

oil side ring(s) end gap 0.90mm

Check your service manual to make sure. :thumbsup:

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I ordred a new cylinder, gaskets, rings, and circlips. Hopefully this will solve the problem. I will check the cylinder head for leaks while I have it off. Hopefully Ron will stand by his work if it is a problem caused by porting. Thanks for all the info guys. :devil: You guys are awesome. :thumbsup:

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