Spark Plug Update...!! Good news... And a question (vacuum hoses)

[The Dark Shadow]

Okay, so I put in some Denso iridium plugs...

Sure, some of you say, "Why bother with iridium...?? Keep what is in the manual!!"

Well, I got the right size, shape, and heat value iridium plugs (equivalent of "8" heat value if we compare to NGK).

I put the plugs in, added some fuel system / valve cleaner to the tank, and ran it. After it came up to temperature in a few minutes, the thing started blowing white smoke for 4 to 7 minutes (can't quite remember), and then it cleared up. Took her for a good ride and now the thing runs without the sweet rich smell that it was doing before with the .8mm gap (instead of the required .9mm gap). Also, it heats up to prime operating temperature more quickly. I just hope the sojourns with the wrong plugs didn't/doesn't leave permanent build-up on my valves and cylinder heads.

Question: What are the symptoms of vacuum hose leaks...?? I don't think I have an issue, but this seems to be something that crops up from time to time, so I should prepare myself with understanding.

Many thanks!!

 

[bdalameda]

White smoke for a few minutes after starting is usually just water condensate in the exhaust that is evaporating.

Usually a vacuum leak will cause erratic idling and stumbling off idle.

 

[Al st1100]

Usually a vacuum leak will cause erratic idling and stumbling off idle.

all depends on how big the leak is.

 

[The Dark Shadow]

White smoke for a few minutes after starting is usually just water condensate in the exhaust that is evaporating.

Usually a vacuum leak will cause erratic idling and stumbling off idle.

It was NOT condensation... Of that I'm well aware. Thanks though, and thanks regarding the idle.

 

[bdalameda]

It was NOT condensation... Of that I'm well aware. Thanks though, and thanks regarding the idle.

Well - if it is not caused by condensate collecting in the exhaust and then when the exhaust heats up enough to boil it off - you may have a coolant leak from a head gasket. White smoke is typically either water vapor or caused by coolant. Blue, grey or black smoke is usually from oil or an excessively fuel rich mixture. Not much else that it could be.

 

[TerryS]

Vacuum leaks between the TBs and the engine can also lead to unusually high idle.

 

[The Dark Shadow]

Well - if it is not caused by condensate collecting in the exhaust and then when the exhaust heats up enough to boil it off - you may have a coolant leak from a head gasket. White smoke is typically either water vapor or caused by coolant. Blue, grey or black smoke is usually from oil or an excessively fuel rich mixture. Not much else that it could be.

Look at a prior thread I started about spark plugs. My engine was filled with varnish and carbon from the pro shop putting in wrong plugs.

 

[DannoXYZ]

Question: What are the symptoms of vacuum hose leaks...?? I don't think I have an issue, but this seems to be something that crops up from time to time, so I should prepare myself with understanding.

As mentioned, it depends upon which vacuum-hose(s) has leak. After throttle-body can result in higher than normal idle since extra air is being ingested.

Leak in any of 5-way T fitting or hoses going to MAP sensor will make sensor see less-than-normal vacuum. This will cause it to output higher-than-normal load signal to ECU and trick it into injecting more petrol than normal. Resultant richer-than-normal mixture will lower MPG and foul plug with dark soot.

Leaks in EVAP hoses would be more benign.

Monitor your MPG and pull plugs to compare to previous ones after couple of tanks.

 

[bdalameda]

Look at a prior thread I started about spark plugs. My engine was filled with varnish and carbon from the pro shop putting in wrong plugs.

I have never heard of incorrect spark plugs causing white smoke. Plugs can foul from wrong heat range but causing carbon inside the engine or varnish would not come from sparkplugs. A sparkplug provides a spark that ignites the fuel regardless if it is a correct or incorrect plug. Too cold of a plug will allow deposits to form on the plug tip as the tip is not hot enough to keep itself clean but the combustion inside the cylinder is just the same until the deposits on the plug tip cause the plug to misfire. A too hot plug will destroy the plug tip and possibly cause engine damage as the hotter plug can't transfer enough heat away from the insulator, this can cause pre-ignition or detonation which can damage an engine but carbon buildup or varnish is not a result of this in the combustion chamber. Running with a dead or fouled plug can cause unburned fuel to deposit in the exhaust and this will burn off because multiple cylinders are using a common exhaust but this too would not produce white smoke but a darker smoke and unburned fuel smell. Did you ride the bike a long time with a non-running cylinder?? Did you have a misfiring cylinder due to a bad plug? In any case if the engine is running correctly now I doubt you have a carbon or varnish issue in the engine. A good run down the highway will clear anything out of the exhaust caused by a cylinder that was not running.

 

[The Dark Shadow]

As mentioned, it depends upon which vacuum-hose(s) has leak. After throttle-body can result in higher than normal idle since there’s extra air is being ingested.

Leak in any of 5-way T fitting or hoses going to MAP sensor will make sensor see less-than-normal vacuum. This will cause it to output higher-than-normal load signal to ECU and trick it into injecting more petrol than normal. Resultant richer-than-normal mixture will lower MPG and foul plug with dark soot.

Leaks in EVAP hoses would be more benign.

Monitor your MPG and pull plugs to compare to previous ones after couple of tanks.

Thanks! At some point M gone do a full tear down, and I'll check the 5t and the vacuum lines.

I can't trust the local "pro" shop anymore.

 

[The Dark Shadow]

I have never heard of incorrect spark plugs causing white smoke. Plugs can foul from wrong heat range but causing carbon inside the engine or varnish would not come from sparkplugs. A sparkplug provides a spark that ignites the fuel regardless if it is a correct or incorrect plug. Too cold of a plug will allow deposits to form on the plug tip as the tip is not hot enough to keep itself clean but the combustion inside the cylinder is just the same until the deposits on the plug tip cause the plug to misfire. A too hot plug will destroy the plug tip and possibly cause engine damage as the hotter plug can't transfer enough heat away from the insulator, this can cause pre-ignition or detonation which can damage an engine but carbon buildup or varnish is not a result of this in the combustion chamber. Running with a dead or fouled plug can cause unburned fuel to deposit in the exhaust and this will burn off because multiple cylinders are using a common exhaust but this too would not produce white smoke but a darker smoke and unburned fuel smell. Did you ride the bike a long time with a non-running cylinder?? Did you have a misfiring cylinder due to a bad plug? In any case if the engine is running correctly now I doubt you have a carbon or varnish issue in the engine. A good run down the highway will clear anything out of the exhaust caused by a cylinder that was not running.

You misunderstand.

The cylinders built up varnish and carbon from the wrong plugs. The wrong plugs did not cause the smoke. They created varnish and carbon buildup. Then, when the correct plugs were installed and the engine actually started getting hot enough explosions to create complete combustion, this build up from running the wrong plugs started to burn off. I'm sure it's not perfectly burned off, however. As Igofar told me, "Replace the plugs immediately because you could be doing permanent damage to your engine."

So much for local "pro" shops!

 

[bdalameda]

You misunderstand.

The cylinders built up varnish and carbon from the wrong plugs. The wrong plugs did not cause the smoke. They created varnish and carbon buildup. Then, when the correct plugs were installed and the engine actually started getting hot enough explosions to create complete combustion, this build up from running the wrong plugs started to burn off. I'm sure it's not perfectly burned off, however. As Igofar told me, "Replace the plugs immediately because you could be doing permanent damage to your engine."

So much for local "pro" shops!

I'm sorry and I will stay quiet for now on but what you are saying does not make any sense at all. All a sparkplug does is ignite the fuel. the heat range of the plug has nothing to do with varnish or buildup. A incorrect plug as long as it is igniting the fuel will not cause buildup internally in the engine. If the plug is too hot it can cause damage due to detonation or pre-ignition but won't cause varnish or carbon in the engine. A too cold plug will foul the tip over time but again if it is igniting the fuel won't cause buildup in the engine. I think you misunderstand the physics of an internal combustion engine. I certainly don't want to argue or come off as a know-it-all. I do have more than 50 years of working on and building racing engines. I won't comment anymore.