85 Oil coming out of exhaust pipe

My son's 08 KX85 has always smoked since we got it. The guy I bought it from toldme that he ran a 32:1 mixture. It has oil coming out of the exhaust pipe, I ran his KX65 at 32:1 and did not have this problem. I have backed the mixture to 45:1 and still have the smoke and oil out of the exhaust pipe. I have not messed with 2 stroke bikes that much. A couple of guys at the race track told me it needs a new top end. Do you guys think that maybe the problem.
 
I'd keep mixing 32:1....


Probably either a jetting issue or its getting time for a top end. Whats the spark plug look like? Have you done a compression test.

If you have no clue on how much run time is on that top end, Its probably good measure to go ahead and throw a top end on it,exspecially if hes going to be racing. :)
 
Its the jetting :prof: I have new topend in mine and my sons. Both do it..32:1 is king!!!!! never change that. Jetting can/should never be fixed by changing your premix. Especially on the little smokers. They love the oil and since they rev to the moon... THEY NEED IT.

Starting off with a a new top end is key when trying to jet a bike but you can adjust your jetting now. Stock topend, stock reeds, stock pipe and sliencer makes it easy to jet so if you have changed any of those you will most likely need to change your jetting as well.
 
Before you go tearing into the carb i would check the packing in the muffler. Packing should be done every 10 hours or so anyways and its alot simpler than a carb
Really? I can have the carb off and cleaned, swapped jets and back on in about the same amount of time. The time you have to take to wire brush all the funk and re seal the can etc. No much difference IMO but I aggree you need to repack that bad boy anyway :thumb:
 
The kx85 will always smoke. They burn oil. You will need to dial in the jetting and repack the silencer. My ktm smoked from day 1 till the day I sold it, but did not drip any oil when I leaned it out a bit in the carb.
 
I would rather see a little oil running out the back on an 85 so you know you are getting plenty of oil in the motor. Kids love to pin it and not shift, so if you are running too lean, you will be doing more than jetting and repacking a silencer, besides pushing/towing a bike back to the truck.

On my old YZ250, I have run the same oil mixture forever. When my son rides it, it would have a slight oil trail running down the silencer, when I ride it, nothing....
 
Only time you should be concerned about jetting is if the bike is running lean or bogging due to being WAYYYY too rich. :thumb: run at 32:1 and let that thing drip oil all over the mx track :rocker: :lol:
 
Mike - listen to all the above advice because it is all good. Personally, I just recently got out of the little 2Ts a few years ago. Those bad boys are meant to rev to the moon - if they aren't run hard, they are going to be spitting oil. I don't think it's anything to fret about :thumb:
 
I would check the jetting and compare it to what it is supposed to be stock. With us not knowing the history of the bike, like have you owned it since it was new? When was the last time it had a new spark plug? Last time it had a top end? What jets are in the carb right now? Is it stock? Pipe? Silencer? Reeds? All these thing play a factor in jetting but start at the basic and work it out. Give us all these things and we'll get you squared away :thumb:
 
Everything is stock, bought used. Was told it had a new topend in october. has fouled 2 plugs, so I put a hotter plug in. I use regular pump gas.
 
stay with 32-1 these engines need lots of oil on the lower end bearings. make sure your not burning transmission oil. replace top end repack muffler and do a plug check rejett leaner if needed to get engine temps high enough to complety burn the mix. as your rider gets better you may need to go richer. rule of thumb always replace or check the top end on a new to you two stroke always assume that it needs a top end weather the previous owner replaced it or not. a properly jetted two stroke will hardly smoke at all.
 
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