telling ur engine health, by exhaust

[Dmajiq]

Is this accurate?




4-Stroke Bike Engine Condition through Exhaust Smoke

May 13th, 2009 Goto comments Leave a comment

#1. Colourless or slightly blue smoke from exhaust
This means that your bike is very good condition. What you can assume is your fuel/air mixture is at the right composition and everything is well burnt is your combustion chamber.
#2. Yellow or brownish smoke from exhaust
Your fuel/air mixture is too lean. Too lean means that there is low fuel but high air mixture in your combustion chamber.
Solution: Adjust the fuel/air mixture at your carburetor (or ECU) accordingly.
#3. Black smoke from exhaust
Your fuel/air mixture is too rich. High fuel but low air intake. This will reduce your fuel efficiency since the black smoke is your unburnt fuel.
The problem might be at this part:
i. Your air filter is dirty or blocked from receiving air from surrounding.
ii.Your choke is closed
iii. Your carburetor is damaged
Solution:
i.Clean/replace air filter
ii.Open choke
iii.Repair/replace your carburetor.
#4. White smoke from exhaust
This happen when your engine oil gets into the combustion chamber.
The problem might be at this part:
i. Piston ring is loose
ii. Piston is worn out
iii. Engine block is worn out/scratched
iv. Valve is worn out/damaged
v. Valve line is worn out/scratched
Solution:
i. Replace piston ring
ii. Rebore block and replace piston
iii. same with no. ii
iv. Replace valve
v. Rebore valve line and replace valve.
Sometimes white smoke can also occur in the morning or you start your bike after it is being left on the rain. The white smoke is the water vapour released from the condensation that happens inside your exhaust. Normally, this happens only for few minutes and then it will be back to colourless again. The difference from white water vapour smoke and white exhaust smoke is the smell. What I can say is, the smell from engine oil being burnt is your combustion chamber is bad and very busuk. Water vapour doesn’t have any smell.


http://xbfish.com/2009/05/13/4-strok...exhaust-smoke/
__________________

[Normk]

Not very much use from a practical standpoint. By the time one sees black exhaust color the condition is extremely rich. Lean mixtures will show white, etc. on the exhaust valves and ports but not visible as smoke from the exhaust. White is normal on a cool day but less to not visible when engine is up to temperature.

These kinds of articles are typically found in old owners' manuals and user publications but try to apply the information and it is wanting.

I like this one though:

"What I can say is, the smell from engine oil being burnt is your combustion chamber is bad and very busuk."

Can someone define: "busuk"?

Running for cover....

Norm

P.S. a very useful exhaust diagnostic tool is an old 4-wire O2 sensor. Ask a techician friend to save you one. Two wire or single wire O2 require a super hot exhaust stream to function but the 4-wire units have a built-in heater which allows them to operate at the outlet of the tail pipe. Hook up the heater wires to a 12 volt battery (they are usually the two wires which are the same color but an ohmmeter will indicate) and clip your digital voltmeter to the other two. 0.45 volts is 14.7 air fuel while higher voltage is rich and lower lean. The ordinary ones range between a maximum of 0.1 volts (very lean) and 0.9 volts (hugely rich). Lots of voltage to mixture charts on the net. Just clip to the end of the exhaust and read. The reason these things get replaced is not that they don't read accurately but because they won't react/change value fast enough for the computer to accurately control the mixture. Deposits and contamination/old age are the issue but they are still able to react quicker than we need to read mixture with a voltmeter. After all, we are only looking for an average not live value.

HIH

[keman]

I think my Ex was busuk, before she died.
(short for Butt Ugly Screaming Unintellegent Kun*) She wasn't so bad when I met her, 27 years of marriage did bad things to her looks and her personality.


Great Info Norm, I will be getting one of the 4 wire sensors soon as I can find one. Should be more accurate than plug chops, and it can read while rolling if hooked up right.

[koolaid_kid]

There are two types of O2 sensors - narrow band and wide band. The type described is the narrow band. It is used by the engine computer to determine efficiency of the fueling system and health of your cat(s). It is not very much use for tuning, unfortunately. A wideband is very useful for tuning as that is its purpose. Not sure how much use you will get out of using a narrow band, but they are not very expensive so it might be worth a shot. I have seen them on sale at the auto parts stores for $30 or less; Bosch are very popular, but many have reported issues with them. I would probably try a Denso unit.
Just be aware that if you go to the auto parts store you will really confuse the workers there, who will want to know what car it will fit. Then you will have to figure out which wires are the heater wires and which ones are the output voltage lines. This may help: http://www.obsessionwithperfection.com/O2WireColor.htm
Here is an article on how they work: http://www.aa1car.com/library/o2sensor.htm
Best of luck.

[hampshirehog]

#4. White smoke from exhaust

My engine is worn out and need rebuilding. Help! Can I claim under warranty?

No....that's not smoke it's water vapour sir. Probably the most common 'engine problem' we used to get. Well, that and when 2-strokes stopped smoking.....

[Normk]

Koolaid's points are all valid, so if you are buying a new O2, it will be better to buy a wide band one but my suggestion was regarding a free used narrow band. Interesting to play with and well worth the investment.

I would certainly buy wide band if contemplating a weld-in exhaust bung, etc. While I no longer own an exhaust gas bench, friends have so can use theirs but the free heated O2 helps me to make some decisions.

Back to the garage as I've managed to waste the day completely to this point.

Norm