I'm trying to get to the bottom of my oil burning on cold start up issues. Since checking the oil seems to be a mistery considering one second it's empty the next it's full, I am thinking the oil valve that keeps the oil in the tank is faulty. When the bike sits overnight perhaps the oil is draining out of the tank and into the crankcase so it wet sumps and smokes terribly until the oil levels out and is pumped back into the tank. So my question is how do you change this valve. I've read that it's in the right hand cover? Does my theory sound plausable?

I wasn't aware of an oil valve. thought it was a convection driven circular system.

There is a valve, it is located in the bottom of the clutch cover. It consists of something that looks like a seal, a ball and a spring. It's function is to avoid that the oil in the channel going up to the head drains back with stopped engine. This way these sensitive parts get oil immediately after start of the engine.

I doubt that replacing this valve will solve your problem. The oil drains via the oil pump back into the sump; the valve only stops the flow up to the head. You could solve the problem by replacing teh oil pump that is worn so much that the oil can drain through but is by far not worn enough not to lubricate sufficiently.

My advice: just live with the smoking at startup.

Auke

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Auke
http://aukemarieke.blogspot.com

so if all the oil on the top half drains back to the lower, you don't think the over abundance of oil in the low end would cause it to burn it off and smoke until it gets recirculated and evens out. I also have read this valve is common to go bad, so what are the symptoms of a bad oil valve.

I see a lot of post about the xt600's smoking terriblely at start up, then some say the do a complete rebuild and it still does it. I have yet to read anyone post how or if they actually solved the problem.

Here is a video I posted in another thread. Notice how it runs for 20-25 seconds before it actually starts to smoke. I would think if it were a valve seal or guide, 1. it would smoke a little all the time, and 2. it would be imediate upon start up. I don't know maybe it is the valve seals :confused1:.

http://www.youtube.com/v/JGtAQLGjsPM

That when all oil is in the sump instead of the tank this could cause the smoking at startup. I can only explain why the smoking only starts after 25 s. is that it takes some time for the oil to get past the piston rings.

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Auke
http://aukemarieke.blogspot.com

...and for crank case pressure to build enough to vent to airbox.

well so far I added a half bottle of SeaFoam to the oil Sea Foam . Not sure if it's available everywhere or not but basically breaks down carbon and cleans internals.. Works very well on all engines. Anyways I was running two quarts of 20/50 and 1.25 quarts of 10/40 so the weight of the oil was a little heavier and thicker. So I put this seafoam, which is very thin, in the oil and ran the bike. With three cold starts the smoking at start up is DRAMATICALLY better and only last for a few seconds. I am leaning to the oil valve allowing too much oil back into the lower end and wet sumping. I am thinking one of two things may be happeing here. 1. the seafoam went in and cleaned and loosened the oil valve and all the oil paths which may have reduced the amount of oil back draining to the lower end, or 2. it thinned the oil out so it's able to redistribute the excess on the lower end much quicker to reduce the amount of burning. The thinning of the oil due to the seafoam would probably reduce oil pressure as lighter oils usually pump more volume less pressure when cold and reduce the effort to redistribute at start up thus reducing the amount being forced into the cylinder. That's my theory as of now. Perhaps heavy 20w/50 oil that is hard to pump could be part of the problem if it's wet sumping or maybe seafoam cleaned the parts. Hard to say. It's cold now so I'll put some 10w/30 in this weekend to change it again and see what it does.

Are you sure it is not oil running down the inlet valve and sitting in the inlet tract ??

That was my original thought, but I am leaning away from that. As mentioned it takes 20-25 seconds after started to smoke. If it was leaking down the intake valve I think it would be instantainious and wouldn't last as long. Also thinning out the oil I would think would make a valve seal worse?

I also noticed it makes a huge difference if it's at a higher rpm such as if the choke is on and the rpms are raised, it smokes a lot more. If you get the bike running and lower the rpms it smokes just a little now. I think the oil pressure is lower and will allow it to clear the overfilled sump without producing much smoke. RPM plays a big factor in the amount of smoke at cold start up.

Hi,

Are you absolutely sure that you havent overfilled with oil?

As has been said before, you need to ride the bike for at least 10 min, let it tick over for a min and check the level within seconds of turning the engine off, holding the bike upright and not screwing the filler cap in to make the measurement. Not following this pprocess usually leads to overfilling and could cause your problems.

Hope that that is all it is

Mark

Has anyone actually had to replace the valve-stem seals or guides with a successful resolution to this problem, or has the solution been more set-up based. My 23k-mile '02 E's smoking like Krakatoa as of very recently, much more than i can live with.

No my oil has just been changed and filled as Mark described.

I have just about eliminated the problem.. It went from litterally can't see out the door of the garage to hardly anything and only for a second or two at cold start up (when the choke is on). The seafoam made a big difference but didn't eliminate it. But now the main trick I'm finding is the choke.. If i start the bike with the choke and quickly turn it off and play with it to keep running at a low rpm with no choke cold it won't smoke. Even after it's been running for a minute and starting to build heat, if I turn the choke on it will smoke. I used to always start it cold and just leave the choke on and it blew smoke everywhere for 2-3 minutes until it was well warmed. New starting method had fixed that. And yes it is oil burning with the choke on & cold.. Smells like oil and is white/blue smoke. Not gas. When heated up it won't smoke even with the choke on. I figure I can control it so I'm not messing with it. It's not the valve seals. I almost wonder if it's not wet sumping, then the choke raises rpms, oil pressure increases, extra fuel washes out the cylinder some, and it smokes.. I don't know but so minimum now I'm cool with it..

If it only happens with choke on then you might consider worn oil rings. Added choke richens the mixture and allows the oil coating the cylinder to be "dissolved" into the petrol air mix. As the bike warms to operating temperature and the piston / sleeve fit becomes optimum the effect reduces. Worn rings of any kind will increase blowback and hence elevated crank case pressures.

It is a bad idea to let your bike ( or any other engine) idle with the choke on. You should ride it gently as soon as the motor is running reliably ( 20-30 seconds) and get it off choke as soon as possible. Idling with choke on will wash away the oil from the bores and cause early bore (and ring) failure. I suspect you are beginning to see this condition.

I dont know why but I see it a lot on the Triumph forum, for some reason Americans tend to start and let their bikes idle on the choke. Even with free petrol, I cannot see the reason for this.