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Old 11-25-2012, 09:17 AM   #12
let's keep going...
geometrician's Avatar
Joined: May 2008
Location: West-By-God Virginia
Oddometer: 1,034
LC8 Oil levels

They'll run pretty low as long as the pump doesn't cavitate from sucking air up instead of oil.

Originally Posted by Deepc View Post
05.5 950A w/ 18,000. I've been running into the same issue. I check my oil once every two weeks or so when commuting around town. Lately I find the oil level at 1/4 from max regardless if I have filled to 1/2 from max a few days before. Balance shaft seal? Front carb throat shows little to no residue. I do get a little smoke out of the exhaust at startup but it goes away after 10 seconds or so. Any thoughts?
I have LC8 customers that are constantly worried about their oil levels and some add oil every ride to keep it "full". I've watched mine carefully (bought used at 13,000 last year now at 28,000) and notice (some of?) these engines set the oil tank level where it wants, and I now check/fill it to that point. I learned that after several rides where I'd start full and check it at fuel stop/etc and it would be back at it's "happy" point- which is towards the lower 1/3 of the dipstick with my engine. I've replaced the balancer seal, checked all the breathers, elbows & lines and there are no obstructions; it seems the crankcase venting, timing & pressures just wants a bit more air in the oil tank. Since I didn't buy this bike new I can't say how it was treated before (or which KTM-problems it started with! )

Suzuki TL1000's have an oil separator I might expirement with that looks like it would fit on our bikes, along with some extra oil tank/valve cover ventilation. I'm considering larger diameter lines to slow/spread the pulses down & allow the vaporous oil to drop out of suspension. I've never owned a motorcycle that consumes this much oil and I hate wasting it when it's so damn expensive!

Originally Posted by Sumi View Post
As for the smoke on startup: I also have it (white smoke for me), and I believe it's water deposit (building up overnight, when the exhaust is cooling) in the exhaust turning into steam.

As for the oil: As I've read, if the balancer shaft seal is leaking, it consumes way more oil than 1/2->1/4 on the dipstick in a few days, and the air filter should be really oily beneath the crank vent. So I guess your bike is behaving normaly.. Mine would consume roughly about 0.5-1l oil / 1k miles.. This is when riding steady @ highway speeds.. Interestingly it doesn't consome any oil at slower speeds..
That isn't enought time in Deepc's description to heat the moisture up & cause vapor to appear at the tail pipe. Moisture vapor begins to appear after 10 seconds and continues until the volume of the mufflers/headers heats up enough to evaporate everything.

As for the balancer seal & shaft they leak more as they wear so it's not a constant- true they usually get replaced once things are messy/bad.

General 4-stroke troubleshooting says visible smoke upon startup indicates your valve guides, valve stems or valve stem seals are worn. The initial smoke is is from the "extra" oil stored between the stems & guides at engine shutdown and is quickly consumed. Of course induction/overlap will attempt to draw oil from them as the engine continues to run but the overall distance the oil must travel down this space is mitigated by the viscosity & surface tension of the oil- it has to travel 1-1/2-3" (depending on head design) along the length of the valve stem/guide interface, whereas at the cylinder/piston interface it only has to travel a 1/4" to 3/8", as well as having to seal combustion pressure. Here's where thicker/better quality oil helps older engines quit burning oil.

When a 4-stroke continously smokes piston/cylinder/ring sealing at issue. This is easily seen at night in the headlight beams of someone behind you when accelerating from idling from a stop light. During the red light oil builds up in the cylinder head & exhaust when pressure/temperature/cam overlap effects are lowest. I always tell my riding buddies when I see it because it can be really faint if things haven't progressed far.

One more reason to ride to the pub together
'06 KTM 950 Adv 'S'
'03 KTM 250 EXC
'87 KLR650 - <200K miles "Like the Energizer Bunny, just keeps going & going..."
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