still smoken??

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20warrior00

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i just rebuilt the head, put new valve guides, valves, seals and valves seated and it still smokes, the piston is a wiseco about 1.5 years old (i think, cant remember) and the rings are about 6 months old (i think lol) and it still smokes. it smokes the worst at start up but once it starts to warm up it smokes a bit less. what is it the piston and rings or something else??
thanks
 
you positive everything s the right size? (piston, rings, bore? Rings the right thickness for the piston?) Also did you remember to stagger the rings on the piston?
 
Did you have the cylinder honed when the rings were installed 6 months ago?

How did you break it in after the rings were put in? Did you give it a good run or did you baby it and keep it slow? How much did you let it idle during the first couple hours?
 
no i dident have it honed (i no i should have, crap) and i let it run (idle till it warmed up) then shut off to cool down, doing afew heat cycles, i kinda babyed when ridin it for the first week. it never smoked when i put new rings it just started about a month ago, thats why i rebuilt the head.
 
Sorry to tell you this, but you did all the things you're not supposed to do bud. You always need to hone when new rings are installed. When you install new rings they will never perfectly match the cylinder wall, thats just the way they are, that cross hatching from the hone is there to perfectly wear the rings into the correct shape. The heat cycle thing is also a big myth, idling it like that is the last thing you want to do right after an install. The harder it gets ran, the more pressure is put on the rings, and it's that pressure that really makes them push tightly against the cylinder walls, and breaks them in correctly.

The right way to do this is:

Install new rings and hone cylinder

When ready to break it in, do not give it warm up time. 20 seconds is ok but try not to do any longer than that. The sooner you get pressure on those rings, the better they're going to fit in the cylinder because just sitting and idling will wear down the hatching. Another terrible thing to do is dog it around during the first couple hours, if you're revving it so low that it is chugging and sounds labored you're going too slow. Keep it up in the mid rpm's, ride it like you normally would. Don't totally beat the piss out of it, you don't want to be looking for the rev limiter. Also try to vary your speed, keep it constantly accelerating and declerating on the engine, and even give it a few short 3/4 throttle runs, maybe in 5 to 10 second bursts, then decelerating again, let the engine slow it down.

You break it in like that and you'll never get oil past those rings, lab tests have even proven this method vs the dealer recommended easy break-ins. They've taken 2 identical brand new motorcycles, and broken in one the easy way, babying it and never revving it out, and then the other doing as I just described, and the easy break in method produced 2-4 hp less on the dyno after the break in process was completed because the compression was that much stronger with the harder break in method.

I practice the same method. Within the first 5 minutes of bringing my brand new 700 home I was doing a 3rd gear wheelie up the road.
 
youll need to measure it and make sure your new rings will be in spec still... youll probably be good, but its hard to tell....

i also agree with yamariders break in procedure, i've always heard that it is the decelleration that breaks rings in... is that right?

my dad tells me that back in the day when him and his buddies were always rebulding 350's thats what they would do... he said "it will smoke like a bitch for a couple miles but then all in the sudden clear up and then you are good to go"...

when i bought my new car i was wishing i had the chance to break it in like that but instead i ended up driving about 50miles on the interstate home from the dealer...

i've never heard such a scientific explaination on the ring pressure but it all makes sense...

i assume this break in procedure is good for all motor? even 2 stokes?

one last thing... from what i understand smoking on start up is due to valve seals... and it makes sense, oil from the head leaks past the seals and sits on the piston till you fire it up
 
I broke mine in the exactly the way yamarider described. when i started it (it was in the late december about 15 degrees out) i just played with the throttle and revved it up and down for a little then jumped on it and rode it around a work the engine some, but didnt run it hard. i constantly played with the throttle while riding. has served me very well, had it together for 10 months now and it does not smoke.
 
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