oil leak in #4 cylinder (valve seals leak) --> how long does it take to stop smoking

[Guest]

Hi all

I solved, last Weekend, an issue with one valve seal leaking. The oil went through the seal, all along the intake valve and was burned, so I have the #4 exhaust tube full of oil, burned or not.

I solved the issue last Weekend, and I ran the bike few kilometers (less than 5 kilometers) today to go to work. Once arrived, I still had a little smoke at the exhaust. Less than before solving my issue, but still something....

So I wanted to ask to this forum for some feedback, about how long does it take to burn all the oil in the exhaust ports?

I will continue to drive it to see the evolution but I wanted to ask first.

thanks a lot!

[geol]

The valve stem oil seal is designed to allow a bit of oil to go onto the valve stem through the seal. if the seal is shot, too much oil will go through and you will get puffs of smoke when starting the bike as the oil has had a chance to pool and sometimes when downshifting. If your bike smokes constantly, then this is a sign of another issue. If you replaced the valve stem oil seal(s) that were letting too much oil by and the bike still smokes, there isn't a lot of oil in there and should have been burned fairly quickly as the exahust runners are hot hot hot. By the way, be a sport and go to your profile and edit your signature and put your bike year/model in so we know which bike is being asked about although valve stem oil seals are valve stem oil seals. If you removed a valve to fix one, why not all of them? If one seal was in need of replacement, likely all of them are in poor shape.

[boris.h]

yep, thanks for the advices. I also heard / understood that the oil seals must admit some oil going through to lubricate the stem. I had too much oil on the stem, touching it with my finger when the carbs were removed. That's a mistake. And the bike is smoking constantly when hot. Now I am pretty sure that this is a broken ring... Maybe the oil seal rings, I'll try to discover it tonight...

[chuck hahn]

Its time for a full replacement of all the stems seals. May as well lap the valves while the head is off also. Bad seals..if gone far enough..will constantly smoke too just like a bad oil ring would.

[boris.h]

Yep. I changed the valve stem seals last week. They were OK in fact... I was disturbed by a lot of oil on the stem... but this oil came back from the cylinder.... i removed the cylinder yesterday and found the oil rings with their cut exactly facing them... I turned them to 180° and turned also the other rings. I'm pretty sure that the burned oil came from there but today this is the time for reassembling. Going to check this tomorrow for another start and ride...

[geol]

Did you check the ring gaps while you moved the gaps back into position? If all are lined up, you will get the oil issue I supposed. I have never had this happen when I installed rings with the gaps oriented properly to begin with. Did you install them originally and put them where they should be at that time?

[boris.h]

Oh crap...so I checked the rings all were OK even the angular position and the play for the first and the second d... but oil rings were exactly facing them... maybe I have no luck and they moved during the installation, or maybe I forgot the check them... I put them at 180°. Mounted all once more. It started immediately. I did another Turn (2km) and came back. Less smoke and the plug does not seems to be oily anymore. Sooty (maybe too rich) at idle but not oily. Still a little fume, but I dont know if this is the oil burning inside the exhaust or another thing... New valve seals, rings OK (even the gap of each ring)... only 2 km and still some smoke at idle. Any advice?

[chef1366]

Did you hone the cylinders and beat it hard on the first start up? There is a small window to set rings.

[geol]

Don't worry about smoke or compression till the rings cut the hone and seat. Will take a few hundred miles and best done by varying speeds and not droning at a single speed.

[boris.h]

ok, thanks. But, there are only one of the four cylinders that leaks. If it could be normal, it xould be the 4 cylinders that could leak.. there is not any oil on the other cylinders...
OK, so I think, also my exhaust system is full of oil, even for the muffler. I can not say how many, so maybe this is the oil that is on the exhaust system, that is smoking.

This morning I drove it to the job, only 5km. the bike only went for 15min..... Once I arrived to the work, I saw that oily smoke at the exhaust. I think there is less smoke than before, but the bike is still smoking. If this is only the oil inside the exhaust system I won't get any oil on the spark plug. Checking this at 12.
But:
- valves are new,
- valve stem seals are bran new suzuki ones
- rings are new, they are all at 120° inside the cylinders.

I just used the same head gasket. I have compression and the bike runs on the 4 cylinders, so I do not think oil could go inside the combustion chamber if the head gasket is ok...

So my first question, at the biginning of this post is, if someone had the same issue, oil leaks inside the exhaust system, how many time and kilometers to remove all the oil and the smoke stopping?

[boris.h]

ok, so after having checked the rings, the valves seals, all is new... but still smoking. I just finished to sync the carbs, the bike idle great, with no lack or anything else. But the #4 plug is still wet. I don't know if this is wet of gas or wet with oil. It leaks through the exhaust seal, and what it is going out is black. So I think this is oil, but the smoke is not blue, even grey, this is white. I think I'll have to ride it, a lot more, whitout being affraid of something. The engine has only 30/ 35km, this is not a lot. Maybe I need the oil rings sealing. Maybe the leak comes from another side.... I don't know anymore.
The last think I suspect, I re-used the same head gasket, which I re-torqued few times (3 / 4 times). the bike runs on the 4 cylinders, so I do not suspect the gasket leaking, but maybe this is a mistake and I have to buy another one....

[boris.h]

I'll re-torque the head tonight...

[boris.h]

ok! For those who find it interesting, yesterday I re-torqued the head. The oem and nuts can go until 40Nm of torquing.
So, working one nut by one nut,
- unscrew it until you feel it free
- retorque
--> go to the next nut

This morning, no oil leak anymore...... have to drive it more, but I think I've found my issue. I checked the torque of the nuts, before doing re-torquing, because of the cylinder gasket, the head, the head gasket, going in their own place, the torque decreased while doing the first heat cycles....

[geol]

Sure hope so... good luck! Let us know if this fixes your issues after a chance to ride the bike some!

[boris.h]

I rode it today, only 10km to go and come back to work... But enough to let the bike heating. I have still burned oil on the spark plug (which is full wet black). I tried to check the exhaust while riding, clossed throttle no smoke, full throttle, no smoke, there is smoke after closed throttle for a longer time, when I start to blip the throttle.
The engine has only 100km since this morning. jetting is good, Tomorrow I'll get the tank full of gas for longer trips and gas consumption testing.

Since Ire-torqued the head, the bike does not smoke anymore at idle. Before, when the bike was hot and idling, I had lot of white / grey smoke directly behind the exhaust. Today, nothing at idle.

More things: Now, when I start again the bike I can see even when cold a little smoke cloud and then nothing more. Like the oil in the head being swallowed by the lack of pressure (closed throttle).

Then, I can add I milled the head, removing few mm of the valves guides. BUT, there is not that same phenomena on the other cylinders. Only this one.

I don't know, about these bikes, what is the oil consumption when the break in procedure... I just know I check it everyday and, for the first 100km, I did not add any oil (the level is still in front of the max mark in the side window).

Also, I can add that I do not have the central stand anymore, so everytime I look at the oil level, I try to check it moving the bike like it was on its central stand.