I may have done something stupid, white smoke from exhaust By glavey (Read 5,123 times)

[glavey]

I recently changed the oil in my scoot (2011 taotao atm50-a1) from 10w-30; what everybody seems to use, to 15w40; what the manufacturer/owners manual recommends. The only 15w-40 oil I could find is diesel oil, specifically Shell Rotella T.

Before I bought the oil and put it in the scoot, I researched if other people had used diesel oil in their scoots and other air-cooled 4T's. It seems may people do this, including guys from Ooty's Scooters. I checked the back of the oil container and it is stamped with "api service cj-4/sm" so it appears to be rated to be used in spark engines as well as commercial (diesel) engines.

I bought the oil, did an oil change on my scoot a few days ago. Now today when I was fiddling around on the scoot,  I noticed that there was a very small amount of white smoke coming from the exhaust. Of course I stopped the engine immediately, and looked online for the causes of white smoke from exhaust.

It seems that with water-cooled engines, it means coolant in leaking in to the combustion chamber somehow; not really relevant, or the smoke is actually steam from moisture in the air; quite possible as it has rained for the past 2 days here.

On an air-cooled engine it means oil is being burned, the same steam-from-moisture thing, or the valves are leaking oil into the combustion chamber.

I did, about 2 months ago, adjust the valves to .002 intake and .003 exhaust. I don't think the valves are out-of-adjustment yet, but really anything is possible with these chinese engines.

Should I start the engine up again and let it idle and see if the smoke goes away, confirming the steam-from-moisure theory, or should I let the engine cool down and check the valves? Or do something else I haven't thought of?

I should also note that at the time I changed the oil, I also installed a oil temperature sensor in the bolt hole where the oil drain usually is. I don't see how this could cause me to burn oil but I might as well go for full disclosure. Also, when I filled the oil, I was on the center stand and I added just over 700ml of oil, bringing the oil to midway on the dipstick when checked by not screwing the dipstick in, just putting it against the threads.

Edit: checked the spark plug; it is dry, no oil.

[Deleted]

sounds like condensation. if the plug is dry then it's not oil.

[adamhoyer]

Once you changed the oil and you let it idle for 3-4 min  then did you check the dip stick 3-4 min after to see if it was not low?

[Alleyoop]

Many use 15x40 diesl oil for break in when the motors are new. You should put in 10w40 oil Get it at your auto parts store Castrol GTX which is all I ever use also Valvoline is a good brand etc..
Alleyoop

[steelblade]

Thumbs up on checking the oil. If it's an oil leak, it might be enough to see a change in the level.

It MAY be just moisture on the engine as you said, but you're right to be cautious about just running it to see if it goes away. A real problem could develop from that. If possible, I recommend waiting for the weather to dry out and try again. You can also try drying the engine with some towels, but the residual heat may have dried it out already unless the air moisture is still thick even if it isn't actually raining.

[glavey]

Jul 9, 2014 15:38:22 GMT -6 Alleyoop said:

Many use 15x40 diesl oil for break in when the motors are new. You should put in 10w40 oil Get it at your auto parts store Castrol GTX which is all I ever use also Valvoline is a good brand etc..
Alleyoop

I'm not sure if I technically am still in break-in or not. I installed a 72cc bbk shortly after I bought the scooter and have only put about 300kms on it... in 3 years.

Yes, I checked the oil after running the engine for a few minutes, still half way up the crosshatched part of the dipstick. I changed the oil about 3 days ago and have started the engine and checked the oil everyday since. Same level on the stick.

I also checked the valves and they were still at .002 and .003, however I did a little google searching and I read that after you install a bbk, since you are increasing the power output you will get a corresponding increase in heat generated. That seemed quite logical to me so I re-adjusted the valves at .003 intake and .004 exhaust.

This is the first air-cooled engine I have really worked on, besides lawn mowers. The valves are louder than I am used to, although I can only really compare their noise to car engines I have worked on. Is it normal for the valves to be clearly audible when the engine is running?

Regarding the oil grade; I read on the scooter doc manual that if you live in a warmer climate you should run 10w40 instead of 10w30. I live in one of the northern states that shares a border with Canada; would that count as a cold climate?

[Alleyoop]

You have to be in the very cold climate, 10w40 is good for well below zero so not a problem.
Alleyoop

[glavey]

Ok, thanks. Just to make sure, is filling the oil to the halfway mark acceptable, or should I be filling it to the top of the crosshatch?

Also should I still consider my engine in break-in?

[glavey]

I found the cause. It was the crank case breather hose coming from the valve cover spitting oil into the intake.

Is it normal for that hose to spit oil even at idle?

[jct842]

No....if oil is over filled maybe. Could be blow by if oil level is correct. Until my 150 was wrecked at 5000 mi I had a hose from valve cover just hanging under the engine and never a drop came out.

[Guitarman]

Alley, Bash,

When checking oil, should you put the stick all the way in? (screw it down)
And should the bike be on the center stand?

[glavey]

I don't think the oil is over filled; here is the oil level with the scoot on the center stand and the dipstick just pressed against the threads:

[cyborg]

300 kilos!!! whats that like 10 miles???!!! so you have like a little over 200 miles on the new jug,,,past breakin? close enough i would think,,,white white smoke (water) or whiteish blue??(oil),,,,,,,,no strange noises?? ,,,run it,,,,,,,a little smoke happens on a new build,,,you may not be broke yet but it's close,,,and i always test my oil cap/dipstick screwed all the way in so looking at the pic at it's level you may be a little overfilled which may be contributing to the smoke

[Bashan]

I put the bike on the center stand, don't screw the stick in, and fill up to the top of the X's but not onto the smooth part. The 150s vary from 750ml to 850ml even on identical looking engines. I've taken them apart and the insides can look very different. One of them had a real small port going into the case below the fill spout. It took forever to get 750ml in the thing and I thought I was doing something wrong. I split the case and the hole was about the size of a grape! Grrrrrrrrr!

[glavey]

The smoke is white, not a hint of blue. The owners manual as well as many people online say to check the oil with the stick not screwed in.

Also, the owners manual says to add 900ml, but I think that is too much. Everywhere I look online people say 750 to 850ml, just like you said bash.

Could it be that since I don't have too many miles on the new cylinder/piston/rings that the rings haven't fully seated yet and are allowing more-than-usual blowby gasses?