why is it still smoking ???

[Trimotomike]

well i got this old 200s ive had running , she smoked pretty bad so i had new valves and seals put in the head , honed the jug and put in a brandnew piston and rings . it starts right up and runs fine for about 20 mins then it starts smoking not bad but enough to see . i truly dont understand whats going on . someone help im just about ready to junk this darn thing...

[TeamGeek6]

Oil or fuel smoke? They can look similar.

Cant just hone an old cylidner unless its proven the bore is round. M'guess is that it wasnt, and the rings didnt seal.

Need to measure the bore diameter in at least 8 places. Theres usually a change in wear pattern near BDC. either that or a valve guide is worn out too far for the seal to cover.

[james9r9r]

Maybe just the cold weather/fog you know what I mean ?

[Macs]

Was it burning oil before you did the rebuild? If so you could have a buildup of oil in the exhaust. When it gets hot it starts burning it off. May take a while to clear out.

[XL-erate]

I'll assume you staggered the ring gaps around the piston & didn't line them up. Did you check to see what your piston/cylinder clearance was after honing? Many shops hone it out a few thous' too far.

May just be that the rings haven't seated and it's getting a little glaze on cylinder. That usually scrubs away and rings seat after the engine has some hours on it. May not be anything to worry about at all, ride it, see if it clears up! It's best to not put hard time on it thrashing it until the rings seat and it has some hours on it.

[Danold]

when you put a new piston in it was it the same size? If you hone the cylinder, it takes a little off the bore. If its a light none job then just keep beaking it in and get the rings seated. Was there any sraches that didnt come out when it was honed? that could cause smoking too.

[SWIGIN]

useing a old bore is not the thing to do if you want no smoke

plus you have to give the rings time to seat in

[Trimotomike]

the ring end gaps were staggered and the bore looked really good and took very little honeing . the bike smoked really really bad when i first got it running , i mean if it sat it one spot running for more than 30 seconds you cou.ldnt even see the machine through the smoke cloud . the local honda shop did the valves and seals i would hope if the guides were to worn they would have said something but thern again maybe not . if it was burning oil would the plug be black and wet ???it is black but dry and sooty . oh and another thing i have not ran it much but i do check the oil after running it and i havent had to add any . could it just be burning old residue off ???

[TeamGeek6]

" the bore looked really good and took very little honeing"

Doesnt make any difference what the bore "looks like" only takes 005 inches defect to cause oil burning, and your eye isnt trained to see that.


" the bike smoked really really bad when i first got it running"

Thats not good

", i mean if it sat it one spot running for more than 30 seconds you cou.ldnt even see the machine through the smoke cloud "

Thats not supposed to happen on a 4 stroke

". the local honda shop did the valves and seals i would hope if the guides were to worn they would have said something but thern again maybe not ."

More like "they may not know how to check them"

" if it was burning oil would the plug be black and wet "

Maybe not.

"it is black but dry and sooty "

Its no good, replace it. Could be fuel smoke from misfire

"oh and another thing i have not ran it much but i do check the oil after running it and i havent had to add any . could it just be burning old residue off"

Not likely, most of that will go the first time it gets hot. Doesnt mater if the oil level is up, only takes a few drops of oil to smoke badly.

Do NOTHING else till a new spark plug is installed and NEVER try to run one thats fouled like that, especially in a new engine.

Put a new plug in, get it running, smell the exhaust and make sure the fuel isnt too rich. IF not, then ride it easy for a few hours and see if the smoke goes away, if not, then must tear the cylidner down and measure the bore in 8 places, it probably needs boring and honing, especially since it "smoked badly" in the first place.

[Danold]

the ring end gaps were staggered and the bore looked really good and took very little honeing . the bike smoked really really bad when i first got it running , i mean if it sat it one spot running for more than 30 seconds you cou.ldnt even see the machine through the smoke cloud . the local honda shop did the valves and seals i would hope if the guides were to worn they would have said something but thern again maybe not . if it was burning oil would the plug be black and wet ???it is black but dry and sooty . oh and another thing i have not ran it much but i do check the oil after running it and i havent had to add any . could it just be burning old residue off ???

My 200x was the same way. I bought a used cylinder and piston in good shape and gave it a hone before I put it on. It smoked like crazy but I never had to add oil. Well after putting around in the yard for a couple hours the smoking evntually started to quit because the rings were becomiong seated.

[Trimotomike]

ok well im gonna get a new plug and just run it gently around my back yard to see if the rings just need to be seated . it does seem to smoke black smoke a little when i first start it up and rev about half throttle and i can smell fuel in the exhaust when its runing , i am gonna play with the carb a little see if i can get it dialed in . i may put a slightly smaller jet in and see what happens . its got a 100 in it now seems kinda big to me when my buddys 250ex had a smaller jet in it stock than my 200 has . thanks for all the input you guys are great .

[SWIGIN]

100 might be right for the main...i know 83-85 200x's came with a 108 or 110 main jet.

try to drop the needle (or raise the clip) since the main jet does nothing at or below 1/2 throtle