93 300 king quad 4x4

Cold start.. Have to use a little bit of throttle idles good runs great

After about 20 mins the ATV starts smoking steadily not to heavy and not thick more like a thin smoke and not from the pipe from around the cylinder area!? I've checked for oil dripping on exhaust and such but can't see any ... Also now that its been running for a bit it has a rough idle wants to die and using the idle screw does nothing up or down only way to keep it alive is messing with the throttle adjustment nut on the handle bars and if it does shut off its kinda hard to start BUT even with these issues it still drives great no popping banging or bogging what gives ?

While cold none of this happens idle screw works good while cold and no smoke from pipe or cylinder area while cold

Can't tell what coulor the smoke is cuz its all seperated and not coming out of the pipe looks to be whitesh kinda smells like oil maby not sure really what burning oil smells like

oil level checks good when cold below the top hash marks on sight glass but after riding it shows overfill and once engine is completely cold it goes back down to just under the top hash marks I'm lost any comments would be great thanks !

 

Leak down test can give you pretty accurate condition of the valves and rings.Plus not a bad idea to check the valve clearance and check compression. Sounds like if it's smoking only after it warms up could possibly be oil blow by past the rings into the combustion chamber. Plus look at the plug.If it's carboned up or oily that's another sign.Even a worn needle and seat allowing too much fuel can cause one to smoke a little.

 

Hey opt thanks for the advice I have no tools for the compression/leak down test so I'll have to bring it to a shop I guess for that

I hate to say it but yes my plug is black and has oil on it ..

Any info on what to look for with the needle and seat ?

And also why would it be coming from some were around my cylinder ? My plug cap is black with carbon from the smoke I wipe it off after every ride its red so I can see all the black

Wasent looking forward to doing a rebuild after only just buying it lol oh well

 

Hard to see wear on most float needles but ethanol eats rubber tips up over the years,plus sometimes you can see a small wear ring on viton rubber tipped needles or shiny worn spots on needles that have a bare tip. Oily plug isn't a good sign,but again this could be from too much fuel also.If you have oil around the cylinder this can be from a head gasket or base gasket leaking also.My thought is still piston to cylinder clearance increases as it gets warmed up and rings can loose seal against the cylinder walls causing oil blow by.If it's the original piston you've gotten your money's worth.

 

So I guess I should start looking into a rebuild shall it be a full rebuild piston rings hone or maby bore ? Or could I get away with just rings if walls arnt to bad and gasket set of course

 

On this you need the specs from the manual plus measure the piston to cylinder clearance. This determines where just cleaning up the bore and installing a standard set of rings or where it needs to be bored to the next over size that will clean the cylinder up. General rule of thumb is if the piston is over .004 clearance then time for a new over size piston. If you take the top end down let a shop measure it for you if you don't have the tools. Or you can do a rough check with feeler gauges like shown towards the end of this video.

 

OK thanks for your help .

Do u think the smoke around the cylinder would be a exhaust leak from the donut maby ?

 

Possible,either that or an exhaust manifold gasket leak. You just have to find out where it's coming from.

 

ok thanks

So today is a pretty cold rainy day and I took the bike for a hour run and it ran great no issues at all

But the other day it was 25 c out side which is pretty hot in Canada where I live anyway and it ran like complete crap idle very low trying to die idle screw wouldn't work up or down choke made the ATV die just a horrible ride

So any ideas on why it runs good in cold rainy weather and runs very bad on hot days

Starting the ATV on both days was bad it doesn't like starting I have to feather throttle a lot and if I use choke it won't start at all pull cord refuses to start it unless the ATV was just shut off ??

I'll deal with the smoking eventually not really botherd by it

But the running issue is driving me nuts