my yx 150 is blowing more smoke then a 2 stroke why ???

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you know.... a video of just how much smoke its blowing would be REAL helpful... but have you been thrashing it? changed the oil lately? to much oil will often cause it to blow smoke.. rings might be shot to.. its hard to tell without actually seeing... we can only go by the information YOU give US. and well.. there is sweet FA to go by :lol:
 
i cant get a vid of it but put it this way when i first start the bike you sort of have to stand back after a bit ofriding the smoke dose go alittle but when i gas on it blws like a 2 stroke the bike is new and rode it 3 times ive had the head off and everything feelstight i have only about 450 ml of oil and shuld have 900ml i just had the valve clearences done and since then it has been blowing more then any 2 stroke i have every seen and i have one of them 2 do u think it could be the avle clearences
 
same happened 2 me mate. once i got my china bike mechanic to do the valve clearances its been smoking like a 2 stroke. Mine calms down as well after a while. It burns out my oil.
 
If you dont have enough oil it is bad too.
You saidyou only have half of what itsment to??
That will make the ring wear out quick as with not enough luberication
 
valve clearance wouldn't cause that much smoke....
u say the bike is new, what kind of run in did you give it? like how did you ride it for the first couple hours? and what oil did you put in exactly?

sounds like you've killed your rings, easy fix but answer the above questions
 
daveborntoride said:
yeh i know but it should still stop the smoke as it is not overfilled
Click to expand...

running it with not enough oil can cause the rings to burn, and the small amount of oil that gets up there could be getting through and burning with the fuel in the bore...
just a suggestion, but they do have a recomended oil level for a reason;)
 
Come on dudes ... adjusting the valves can't possibly make the engine blow smoke ...

If he's had the head off , he's most likely left something out (rubber o-ring on the oil gallery if it's a Honda type YX150) ... or damaged the head gasket ...

If he's had the cylinder off and replaced the rings ... then he could possibly have the ring gap staggering wrong as in all the gaps lined up with each other ... or he could have stretched the rings too much when placing them on the piston effectively "egg" shaping them ...

Overheating a new motor by letting it idle too long , over revving it , not allowing it to cool after short bed in runs , or running too lean jetting can cause the rings to over expand and that in turn causes the ring ends to butt together ... the now over sized rings push hard on the bore wall squeegying out the oil , which in turn scuffs the bore and wears the rings ... After the motor cools off ... the rings no longer seal ... so your 4 stroker blows smoke worse than a 2 smoker ...

The only other scenario is a valve head has windowed the piston crown ... but the engine most likely wouldn't run in that case ...

If the valve stem oil seals are bad the engine usually puffs smoke on start up and puffs some out when you hit the throttle or back off in gear and engine brake ... but it diminishes as the engine is revved ...

Stuffed rings smoke on start up and get worse as the revs are increased ...
 
And running a low oil level won't lessen the smoke due to the fact that the piston , rod and spinning crank act like fans blasting the oil all over the place (splash feed) ... it's known as "windage" ... and is the very reason why race engines run "dry" sump oiling systems ... Windage and oil roping cause drag and a loss of power ... so the oil is pumped into the vital areas from an external reservoir ... then sucked out by a scavenging pump to minimize the drag and oil control problems ...
 
to tell you the truth im a little confused with the different threads you have going, im not sure if these are all the same engine or not.

but if you can hold the throttle at a steady rev, say 1/4 to 1/2 throttle and it constantly blows smoke then its your rings.
if it only blows smoke in between twisting the throttle then its valve seals...

another tell tail is if you remove the head and see what part of the piston crown is washed away...
washed clean on the center is valve seals
washed edges of the piston is rings....

but yeah like cactus has said you could of damaged the head gasket well installing.
or you have cooked the ass out of the engine causing the ring to collapse(lose tension)

but since you description is missing all the important things its hard to say exactly..
a proper description of how old the engine is, wat oil your using and let us know if and what you have removed and replaced in it...

and yes running low on oil can fuk things...
oil isnt only a lubricant its also a cooling agent..
running it low on oil will mean the piston skirt and bore will be running dryer than normal causing abnormal bore and ring wear, not to mention all the other damage associated..
 
The Dave I know says it's not him even tho' he asks silly questions too ... LOL ... He just bought a bike (GT TTY150) for $200 ... It's got a Lifan 150 horizontal with a broken kicker gear behind the clutch (A Dvdrip job) ... Hahahaha ...
 
Maybe hes oil seals in his t3 turbo are shot so its blowing more smoke then a 2 stroke :O
 
if its a yx 150 with the dirtmax head, the cam is to big and the retainers punch into the top of the valve seals and destroy them, making the engine use oil. The engines are designed and built by monkeys. Not even trained monkeys, just ordinary jungle variety monkeys.
 
I'm guessing your tappets were set a bit on the loose side, so when they're adjusted to the correct clearance the seals get punished even harder.
 
I never liked YX engines from the start ...

It appeared that they were building their engines based on what they read on forums ... Whereas Lifan appears to do some actual research and testing ie 15 mm pin , adjustable semi digital ORK , cylinder fins running in the proper direction of the airflow ... just how Honda runs them ...
 
i like the yx engine, but you can't safely run it straight out of the box. They need some tlc to realise their full potential.
 
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