2009 KTM 450 EXC smokes under load. What could it be?

Hi, I'm new to this forum, but not new to dirtbikes. I bought a 2009 KTM 450 EXC a week ago off Craigslist. It runs great, with a ton of power. It has 29 hours on it, and about 530 miles, BUT, I found out yesterday that it smokes under load out the exhaust, intermediate pipe, and the breather? hose. It doesnt smoke AT ALL WHILE IDLING, and doesnt smoke until the motor is warm. Only after 20-30 seconds of idling (when warm) when I hit the throttle. Where should I start or what can it be?? I appreciate any advice you guys can provide. Please reply with lowest cost solution first. -Dave from bony New England.  

2009 KTM 450 exc.jpg

Often these bikes give a false oil level reading at the glass on the ignition cover. If the bike has to much oil it can cause it to smoke. What color is the smoke?

If that checks okay then the next step would be a leak down test on it. Some of these years are known to have an oil transfer issue where oil can move between the trans and engine.

Often these bikes give a false oil level reading at the glass on the ignition cover. If the bike has to much oil it can cause it to smoke. What color is the smoke?

If that checks okay then the next step would be a leak down test on it. Some of these years are known to have an oil transfer issue where oil can move between the trans and engine

Thank You Hezzdown for responding. I can use all the help I can get. The smoke looks grey, not whitish like antifreeze mix. It definitely has an oil smell to it. What would be a good way to check if the oil level is too high other than the glass??

I would get the bike up to temp and then drain the oil. The owners manual states how much oil should be put in. I don't have my manual handy at the moment. Put in the exact amount per the manual and run the bike and see if there is a change. Also the crank case vent hose is routed to the air filter boot. Pull your filter and look for oil pooling in the boot.

Mine is the same. 2010 450 exc. 55 hours. Somewhere around 1200 km.

I don't think u have the oil transfer problem. When I changed the gear oil I drained pretty much the same amount as I had out in from the first gear oil change.

When I ride hard after about four hours the oil level is about halfway in the site glass I always too up.

My buddy who rides behind me says it puffs pretty good. Maybe ready for rings?

I'm not a mechanic... Any help would be great. Thanks

Thank you Teddy Montana and Hezzdown. Ill start by draining the oil and follow the manual's specs when adding in more. Hezzdown, last I looked, the air filter vwas very dirty. Maybe some air filter oil was sucked in through the carb?? I'll check that next, but thank you for thinking of that. I'd prefer to start with the cheap fixes first, you know. Teddy Montana, the rings were replaced about 20 hours ago or 300 miles ago, along with the valves being adjusted, so that shouldnt be the cause of my problems. Ill look into that if these first few fixes dont work. Thanks guys.

I would get the bike up to temp and then drain the oil. The owners manual states how much oil should be put in. I don't have my manual handy at the moment. Put in the exact amount per the manual and run the bike and see if there is a change. Also the crank case vent hose is routed to the air filter boot. Pull your filter and look for oil pooling in the boot.

Hezzdown, if there is oil in the boot, and its obviously not air filter oil, what would that be a sign of??

Edited by djg010786

It would be a good indication that the oil is overfull. Trust me I play the little oil level game with my 450 all the time. I measure it out and fill it at each change and then keep a very close eye on it. These engines don't hold much so you don't want to run it low.

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