Plugs fouled - VS 1400 Intruder Suzuki Motorcycles

I am assuming it is oil fouled rather than fuel fouled. Oil fouling is usually due to valve stem seal leakage. Most engines have the oil return on the cylinder head at the rear. When the engine is shut off, some oil pools at the rear of the head. If the valve guide seals are worn, then the oil will leak around the stem of the #4 valve and eventually foul the plug. If there are no real issues with the engine other than this one, it is usually best to keep a clean plug or two available and swap out the plug periodically when fouling is detected. Then clean the fouled one and keep for reuse later. If it is happening too often, getting the cylinder head reconditioned is a good idea.

the next time it fouls check the plug when you take it out, if it is covered with oil then you may have a broken ring on the cylinder that is allowing oil to pass through to the combustion chamber and fouling the plug. Or the valves pay be letting oil drain in past the valve seats.

Hi Dale,

Several factors can contribute to spark plug fouling:

- The air/fuel ratio may be too rich as a result of incorrect carburetor adjustment or a poorly performing fuel injection system.
- Worn piston rings or valve seals may allow too much oil to leak into the combustion chamber, leading to oil fouling.
- The ignition system may not be performing properly.
- Prolonged idling or continuous low-speed driving may keep the spark plug from reaching its optimum operating temperature. Using too cold a spark plug can lead to the same problem.
- A dirty air cleaner can create a too-rich condition which can lead to fouling.

Have each of the above checked and corrected.

Fuel, oil and carbon fouling can all be the result of different causes but, once a spark plug is fouled, it will not provide adequate voltage to the firing tip and that cylinder will not fire properly.

In many cases, the spark plug cannot be cleaned sufficiently to restore normal operation. Hence, I always recommend that a plug be replace, once it becomes fouled.

Cheers,

Scott


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Hi Dale,

Several factors can contribute to spark plug fouling:

- The air/fuel ratio may be too rich as a result of incorrect carburetor adjustment or a poorly performing fuel injection system.
- Worn piston rings or valve seals may allow too much oil to leak into the combustion chamber, leading to oil fouling.
- The ignition system may not be performing properly.
- Prolonged idling or continuous low-speed driving may keep the spark plug from reaching its optimum operating temperature. Using too cold a spark plug can lead to the same problem.
- A dirty air cleaner can create a too-rich condition which can lead to fouling.

Have each of the above checked and corrected.

Fuel, oil and carbon fouling can all be the result of different causes but, once a spark plug is fouled, it will not provide adequate voltage to the firing tip and that cylinder will not fire properly.

In many cases, the spark plug cannot be cleaned sufficiently to restore normal operation. Hence, I always recommend that a plug be replace, once it becomes fouled.

Cheers,

Scott


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Ok, you have two problems. Fouling plugs and charging system problems. Work with one problem at the time. I'd work on the plug fouling problem first. What is fouling the plugs? Is it oil or gasoline fouling the plugs. Take one of the fouled plugs out and smell of it. Is it gasoline or oil fouling the plugs? If its gasoline, you have a problem with the carburetor. In this case, I'd need to know what kind of carb is on the engine. Is it the original Keihin or has someone put an aftermarket carb on the engine? Do you know how to check the jet sizes in the carb? If it's oil fouling, is it due to valve guides or rings? Does the engine smoke from the tailpipes? What color is the smoke? Black or blue smoke is caused by a too rich fuel air mixture. White smoke is oil burring.

As for your charging system, the first thing to do it to polarize the generator by momentarily shorting the positive battery post with the armature of the generator. If the generator still does not charge, you need to check the brushes in the generator and the output of the generator.

Good Luck
Steve

It can be cleaned and you must use a sand blaster (by far the best way to clean them) that is just for spark plugs. Another method is to use a wire brush and carburetor spray cleaned. Below is a link to the spark plug sand blaster i mentioned.


http://www.sears.com/shc/s/p_10153_12605_SPM211697464P?sid=IDx20101019x00001a&ci_src=14110944&ci_sku=SPM211697464

If you're running the correct spark plug, you need to determine what is fouling the plug. Is it gas fouling or oil fouling? If it's gas fouling, what type of fuel delivery system is on the bike, carburator or fuel injection? If it's oil fouling, there could be a broken ring in that cylinder or a bad valve guide or seal.

exposure to heat, weather,salt in winter and water make them more susceptible to failure I would change them knowing that my others failed

Fouling occurs when the spark plugs' firing tip becomes coated with excessive fuel, oil, or combustion deposits so that it is unable to produce a spark. A plug can become fouled from continuous low speed driving, improper spark plug heat range (too cold), improper timing (over-retarded), too rich an air/fuel ratio or an oil leak into the combustion chamber. A variety of self-cleaning features are designed into most plugs to reduce fouling.

its not totally abnormal to have gas in oil, fouled plug could have contributed to this as with a fouled plug some gas is not being combusted, however if the fouled plug was replaced and veh is running corrected i wouldnt worry bout it good luck billy