Am I burning tranny oil? pLz help!!

[TwistThatThrottle]

While riding my bike today i instantly realized that my bike wasnt running right. I wont rev up at all and starts to stall out at 3/4-full throttle. I took a look behind me and noticed a thick cloud of smoke following me. I stopped, put the bike in neutral and took a smell of the smoke and it does smell quite strange. This bike was quite spanked when i got it two years ago and I have put a whole bunch of money into it getting it ready to race and I am now a week away from my first hare scramble. I took the plug out and it looks like it was running rich. Do I have a seal gone, something worse, or do I such at jetting? O Its a 2001 250 exc

[TwistThatThrottle]

I did a quick check in the owners manual and this could be considered "steam" which means that i would need new head gasket/rings. They are relatively new though about a year. Any Ideas?

[Pedroski]

Has your coolant level dropped at all?

[Racer38]

Check the tranny level, if its low the right engine crank seal is gone. Its easy enough to fix as you dont have to split the cases.

[Gary jp4]

Smell

Steam is usually more of a white color. It probably smells like whatever stuff you put in the radiator. Open the cap and smell it to get an ideal.

Smoke is usually more blue, and has an oily smell. If you ever smelled it burning before you would probable know it when you smell. Also could smell like 2 st oil but, depending on what oil you are using, it could be more like gear oil. ATF has a distinct smell.

Gary

[Mike in Fresno]

you are on the right track with both problems. You may be able to tell if its a main seal by putting the trans overflow tube in a glass of water. Rev the bike up n down and look for a stream of bubbles. If so its bad. Did you just take the top end off before this ride? If so then maybe its a head gasket leaking water.

[SkyHarborCowboy]

Easy, white steam will seem to just disappear and oil smoke will linger. You can also tell by smell and coolant/oil levels. If the plug looks rich and your jetting before was good its a Seal. If you bike has sat any amount of time your seals could surely be gone from just that.

Either way, they are both pretty easy fixes! I have crank seals to do on 83 CR480R due to the same description ofyour problem!

Joe

[TwistThatThrottle]

I havent had the head off since I put the new top end in a year ago so I'm leaning more towards the tranny oil situation.

[TwistThatThrottle]

I am looking for the seals online, would they also be called the clutch cover gasket? I am on motosport looking at the oem engine case diagram and parts list. I am sure now that it is the transmission as the oil definately lingered and my plug looked like i was running way rich.

[SkyHarborCowboy]

They are called Crank Seals! You may or may not need gaskets for the parts you have to take off to gain access to the crank seals. You will also need at least a flywheel puller. You should change both seals at the same time.

[SkyHarborCowboy]

Make sure you have a service manual for your bike (not the clymer crap either). You will need some information from there.

Joe

[Mike in Fresno]

go to MUNN racing web site, he has a KTM parts guide. You will need the side cover gasket, the seal and the o-ring. Maybe need WP gasket or o-ring as well.

[TwistThatThrottle]

I am about to dive into getting my bike ready to work on for the crank seals. If im sitting on the bike, which side of the engine should i take the covers off of ie which side is the side im replacing.

[Gary jp4]

There is a seal on the crank on each side. If you are burning transmission oil it is the right side. The right side has the primary drive gear which turns the big gear on the clutch so it is wet in the transmission oil. The left side seal is under the ignition stator and flywheel and is dry so it is not coming form that side.

Gary

[Eggbert]

Probably best to do both sides. If the clutch side, which is lubricated with tranny oil is leaking, then it's likely the flywheel side, which runs much drier, is leaking too. If the flywheel one leaks, you may be running lean (airleak) and possibly do some engine damage.

I havn't confirmed my seal leak issue yet, but I'm calling it a clutch-side seal leak. Engine smokes more than it should, but whitish smoke, not blue. This is not abnormal. Not all oil-burning engines make blue smoke. But the smoke does hang in the air a bit longer than steam would.

Also, the plug fouls quickly, and it has a glazed dark brown/black look vs being furry (carbon makes "furry" soot). I think this might be due to synthetic tranny oil vs mineral oil.

Another issue with seals, is that if the crank seals are going, the waterpump seal may also be going. In fact, I'm suspicious that if a water-pump seal leaks antifreeze/water into the tranny, it may help to wear that crank seal out faster. as the seal gets a mixture of tranny oil, water and antifreeze around it.

Finally, crank seals can go if the crank bearings get bad. Sometimes the seal isn't even bad, but due to the crank moving in an oval vs a cricle (not the best way to explain it, but I hope you get my drift), it creates more pressure on one side of the seal than the other. The "other" becoming a gap that can let tranny oil into the engine.

[TwistThatThrottle]

While I have the clutch off (when I finally get it off,) I plan on doing a quick check of the bearings aswell. Also how can I check my bottom end, seeing as my bearings seem to be all going is it wrong to assume I may be in for a new bottom end in the near future? I have pretty much replaced everything on my bike with the exception of my bottom end. One more question. Will burning all that tranny oil do anything to my top end? I have already seen what it has done to my exhaust GROSS!

[Eggbert]

Probably won't hurt your top end, but as you can tell from the condition of your exhaust, not all teh tranny oil burns in the cylinder. This oil takes up space and makes the engine think it has a higher compression ratio. So the engine could detonate if it was tuned close to that before the leak.

Just my guess.

Checking crank bearings...I jsut posted on that and got some good answers, but it doesn't seem to be nailed down. Some say if you can feel play, then it's bad. But of course there has to be some clearance, ...just how much is the question. And some people are more sensitive to feeling small amounts of play.

If there is a little play, say a few thou on a dial indicator, but barely enough to tell for sure by feel, the best check may very well be to spin the crank (with teh plug out) and feel and listen for roughness and other "odd" sounds. That seemed like good advice to me.