Why does this plug look like this?

[hikermikem]

I thought I do something nice for my "81 GS750L, so i bought it new NGK plugs.

The plug on the left is how all the ones I took out looked, the one on the right how all the new ones looked after about 15 miles of general riding...

What the heck is that white scale on the tang? The bike was (is) running well, I only replaced the plugs because that was about the only thing I didn't replace after I brought this bike back from the dead earlier this summer.

Thoughts?

Mike

[Nessism]

Could be additives in the gas. Nothing to worry about I'd say.

[hikermikem]

Could be additives in the gas. Nothing to worry about I'd say.

The tanks has fresh gas with a fair amount of Seafoam in it... I guess it takes a little while to get some color on the plugs.

Thanks for the response,

Mike

[49er]

The tanks has fresh gas with a fair amount of Seafoam in it... I guess it takes a little while to get some color on the plugs.

Thanks for the response,

Mike

The seafoam my cause that effect. I have never used it, but have read that it can cause unusual running after long periods of a bike sitting.

Your porcelains are a little whiter than I would like. How hot does the engine run? It is certainly running very clean. If you don't have any heating /pinging issues, ride it.

Re-do the plug read once you have a fresh tank, without seafoam.

[hikermikem]

Thanks 49er,

I didn't touch any anything, you can see the "old" plug looks like it should with the correct (I think ) color.

Bike seems to runs very well, not overly hot IMHO.

I'll check 'em again after some more miles.

[Steve]

...you can see the "old" plug looks like it should with the correct (I think ) color.

I wouldn't be bragging about that old plug.

Here are a couple of plugs that look more like what you should be seeing. Even these are just a tad on the lean side.



One of them was one that CafeKid took out of his 1100G with about 2000 miles on it. The other came out of my wife's 850 with about 20,000 miles on it. Which is which?

.

[almarconi]

Which is which?

TCK's is the plug on the right, the other one is from your wife's bike..that would be my guess.

[49er]

TCK's is the plug on the right, the other one is from your wife's bike..that would be my guess.

The one on the left is running a little hot. The right hand plug hasn't done many miles and is also running cleaner.

As a side issue, my present cage's plug life specs show a life expectancy of 120,000 kms. Now that's impressive.

[almarconi]

The one on the left is running a little hot. The right hand plug hasn't done many miles and is also running cleaner.

So then....whats the answer? Look at the worn electrode on the left hand plug, that's why I think its the one from the 850.

[Nessism]

The one on the left is running a little hot. The right hand plug hasn't done many miles and is also running cleaner.

As a side issue, my present cage's plug life specs show a life expectancy of 120,000 kms. Now that's impressive.

These cheap NGK's are great plugs but not as durable as the new OE type plugs that routinely run 50k+ miles. I haven't priced the OE plugs but expect that they cost significantly more than $2.

[almarconi]

These cheap NGK's are great plugs but not as durable as the new OE type plugs that routinely run 50k+ miles. I haven't priced the OE plugs but expect that they cost significantly more than $2.

I thought NGK plugs are OEM plugs for the suzuki. That's the brand specified in the repair manual.

[tlepac]

These cheap NGK's are great plugs but not as durable as the new OE type plugs that routinely run 50k+ miles. I haven't priced the OE plugs but expect that they cost significantly more than $2.

I get my plugs from my son who works for an auto store and get them for 5.75 for 4

[mike_of_bbg]

I think I've read here from some members that the NGK Iridium plugs will run for quite some mileage. Probably worth a search. They're definitely more than $2/plug though!

Unlike many cars today, at least replacing the plugs on a GS is not major surgery! With some of the contortions required to reach the things, it can cost $100s to have shops change your plugs (or cost you several hours). It's no wonder they spec 'em to run 100k+ miles.

[flyingace]

I wouldn't be bragging about that old plug.

Here are a couple of plugs that look more like what you should be seeing. Even these are just a tad on the lean side.



One of them was one that CafeKid took out of his 1100G with about 2000 miles on it. The other came out of my wife's 850 with about 20,000 miles on it. Which is which?

.

I agree here. I think the new plug looks far healthier than the old.

If the 850 is stock, the lighter plug came from it.

[49er]

So then....whats the answer? Look at the worn electrode on the left hand plug, that's why I think its the one from the 850.

My assessment also. I thought I would be overstating the obvious so i didn't elaborate, but here goes.

Yes both electrodes on the left plug are showing signs of wear consistent with the stated 20,000 miles life span. The threads on this plug also show heat signs that suggest the engine runs hotter than the one on the right. By general appearances, they both look to be the same heat range plugs.

Are they both running the same grade of fuel?? Probably not the same CR. I'm picking the one on the right is higher than stock CR!!!

Nothing like sticking ones neck out, eh?