well its not a suzuki, its a Honda rancher 350. the thing smokes like hell and gets worse as it warms up, but still runs fine and has plenty of power. and its not just water in the muffler or anything like that because it smells like oil smoke. so i pulled the cylinder and it doesn't seem to be out of round, the piston to wall clearance at the skirt is .004", and the bore is not damaged in any way, its smooth. the piston is fine as well, the oil rings were facing away from each other like they should. the piston ring end gap looks good, and the pistons rings measure true all the way around on my caliper. so its got to be the valve seals right? well i filled the head with water to see if it would leak past the seals and down into the runners, and it didnt. i dont know what to think? anyone got any ideas?

i need to pull the valve springs off and check for valve guide wear, thats all i can think of at this point.

poped the valve springs off and the valve guides show no excessive were, they don't have any play in them. i dont get it, the head and piston are slap full of carbon from burning oil. i just cant figure out were is consuming the oil from. im debating just having it bored and doing valve seals anyway just to end the headache so i know its all good and see what happens. the ol is discusting, its not thin or milky, o water in it at all. but its just gritty and nasty, some metal shavings as well.

it could be valve seals. water is not thin enough to show a leak like that. wd40 is better. But you wouldnt see a leak unless the valves were moving.
Even though the rings were true they may have worn enough to let gases and oil vapor cross back and forth. I had that problem with a je piston this year

well im going to figure on the valve seals being bad anyway, the springs are off and i could change them in 2 seconds so ill just rule that out right there. the thing that im really debating is having it bored or not, i mean, its original bore with the oe piston. i put a ring in the bore and look at the end gap and it is tight. what im wondering is if this is common to just do the top end anyway, maybe its beyond what i can see. i worked at an atv shop as a mechanic for the last year or so and a rancher that smoked like hell was pretty common, and we always just bored them over, but normally the bore or rings would show were. this is the first smokey rancher iv seen that didn't have a problem that just jumped out at me like normall, normally once you pull the top end off its very easy to tell its all shot out and thats why it smokes. this one just didnt give me that in your face reason why it smokes. id hate to bore it over, put it back together and find out it was something stupid like oil in the muffler or something lol

i should have spent more time diagnosing it before i tore into it, its not my bike, im doing it for some money on the side and id rather not have 100 hours in the thing, iv seen the same thing so many times i didn't even hesitate to just tear it down and get ready to send the cylinder off to be bored.

the ring end gap is about .055" on the bottom ring and about .015" of the top ring. i need a service manual here, but of the top of anyone's head does this sound acceptable. don't know why the top ring would have any different gap then the bottom.

sounds like the bottom ring is worn. It shouldn't be that different from the top. If the bottom ring is worn that much it probably is letting case pressure against the top ring and prolly causing some flutter... making it smoke.

measure the ring width and see what the difference between top and bottom ring are.

sounds like you nailed it. i figured the difference in the end gap was so big that it was supposed to be that way, i never could find a service manual to check the spec so i was kind of just waiting on a reply here. so the top and bottom rings really shold be the same as each other then?

this could be solved with new piston rings i imagine, but a bore would probably be the best idea just to cover my ass.

a top end gasket set with valve seals will run the guy 40 bucks, plus piston rings at another 30 bucks. i can buy the whole top end gasket set with an shindey(oe brand) over sized piston and rings, wrist pin, clips, the whole deal for 110 bucks and then $45 to have it bored. seems like i may as well give the guy a whole new top end.

Really depending on cylinder wear you could just hone it. how much ring groove does it have?

is it getting any oil in the air box sounds like blow by if you got it apart just bore it 10 or 20 over put new piston rings and the gasket kit should come with new valve seals you'll be good to go

yea, il probably just gotr 20 over, piston, rings, gaskets, valve seals, ect. if i were to just hone sit and do rings it would only save the guy like 65 bucks. i mean, look at this deal here on ebay. you know, the guy actually gave me an oe honda 50 over piston with the bike, i dont know how he acquired it but im tempted to use it. i just would hate to use up half of the cylinders life just because its what iv got.

http://cgi.ebay.com/ebaymotors/ws/eBayISAP...RK%3AMEWAX%3AIT

thanks for the help guys!

nobody would happen to have an online service manual for a rancher would they? iv got service manuals for alot of different bikes on pdf i could exchange if someones has one in pdf.

Since you have it apart, i'd bore it and put a new piston and rings. That way you know its done correctly. and zophar is correct in the statement about water not being thin enough to find a leak. i use gas or carb cleaner.

well thew bike is back together. ended up being .75 over. its ben bored a few times before apparently. anyway, it runs great, no smoke. but im noticing a few things that concern me. it makes a light ticking sound, and when i wind the motor out it really clicks on the downrev, it sounds like putting a baseball card in the spokes of a bike rim, iv done the valve lash 3 times now, the valves are good. and last problem i notice is that when i kill it, after the motor dies it makes a whining noise for a moment and occasionally followed by a soft clunk.

what do you guys think? im going to give the bike back to the customer in a few hours either way, all he payed for is a top end job and that is fine. but if its something common or simple id like to know.