Spark Plug Inspection

[thundermax]

Inspected the spark plugs today. Left front and back were dry, light brown, looked like they were burning good. Right back was slightly wet, a little darker brown. Right front was less wet than the back right, and little lighter color, but not the clean burn of the left side.

I have been told my air/fuel needles are stuck on the right side and likely is putting too much fuel in the combustion chamber. Bike was stored outside for a long while on it's left kick stand so water/dirt likely accumulated in the right side needle holes.

On running, the cylinders on the right side get hot. The right front as hot as both on the left side. The back right does not seem to get as hot as the others to the touch, but it still is hot.

What is all this telling me? Bike seems to run great. Should I be concerned or just forget and enjoy the ride.

Thanks for all replies.

 

[bazwell]

Pics would help. It may be OK.

 

[naughtyG]

If the bike runs great that is your best indication that things are A-ok.
However, if it spent a long time stored, three things are a must and can't hurt:

1 - sync your carbs
2 - drain all 4 fuel bowls into a clear or white container and look for deposits
3 - give it the Shotgun carb cleaning method

 

[thundermax]

Had the gas tank de-rusted and re-sealed, new gas filter, drained all bad gas. Using premium fuel, stabilizer, anti-water additive, redline motorcycle fuel system cleaner. Carbs were re-synced.

Here is a picture of the sparkplugs.

 

[thundermax]

The sparkplugs are from the right side. The darker one is from the back right and the other is the front right.

The bike runs great. Starts easy. Goes off choke pretty fast after slightly warm.

Should I just disregard and enjoy the bike?

Is this just par for the course?

Appreciate any comment.

 

[KJShover]

On the wet plug, I'd give your a/f screw about a 1/4 to 1/2 turn in.

 

[thundermax]

New with vmax so appreciate all the info guys!

Here are the a/f screws (Ithink). They are kinda frozen, been letting them soak in penetrating spray. The heads not looking too good.

Are these the ones a suggestion was made to tighten? Does that reduce the amount of fuel let in which is wetting the plug?

Thanks

 

[thundermax]

Here are 2 little better pictures of the a/f screws (Ithink).

 

[sdt354]

Here are 2 little better pictures of the a/f screws (Ithink).

Let the penatrating oil do it's thing for a day or so. Grind a screw driver to fit as tight as yoo can. Try to work out then in a little then out like cutting threads. If they come out, replace the needles if they're wrecked. Don't force them or it'll be hard to get them out stripped. When it's resolved, get some cheap plastic plugs for the holes. If you can't move them consider sending them to someone that works on carbs a lot.
Steve

 

[thundermax]

Steve it is like opening a can of worms. You never know when it will end. Consider this, the cylinder fires, the spark plug is darker, but the bike runs great. Maybe I should let good enought alone.

Maybe I will just have some extra spark plugs around. Take them out clean them, rotate back in every once in a while.

What do you think?

 

[PDWeyand]

let the oil do it's job, add more if it does not move, spray it again and wait, after a couple days if you still can't get it to move, I would do the spark plug rotation. Keep spraying the penetrating oil, then try again it might free up, but don't strip it. Good luck

 

[thundermax]

Just thinking why these screws on the right side get is bound up. My thought is the screw has two places to bind up, around the head of the screw and around the thread, and maybe both. They get fine dust and water in there when the bike is on it's side kickstand. If just around the head it would be bound up with packed down hard and tight dirt particles. I used a very small tool to clean around the head and got out some dirt and grime. Maybe this will aid the penetrating oil in doing it's job.

Anyone got an idea on where the screw bind up at, the head or the threads?

Thanks for all comments?

 

[06VMAXIMUS]

Threads usually get crappy. If you have an exhaust pipe that's not as hot as the others, you have a problem with that carb for sure (provided you have checked for good spark on all cylinders). You might have to pull the carbs and go through them if you can't get the A/F screws out. Its not a bad job to rebuild the carbs, just go through the stickies in the carb section of this forum. Or there are several members here that offer rebuilding or replacing. Good luck with it, we have all been there!

 

[rusty]

Pics would help. It may be OK.

Maybe this will help

 

[tugla]

take your time getting those out and replace with new ones. id also turn the other two carb screws on the left side to make sure they dont get stuck also. if you can get aerokroil, penetrating oil, really great stuff.

 

[maxcruiser]

You may think the bike is running right, but by the looks of the plug on the right, it is running rich.

Reading spark plugs is a bit of a science and can pay dividends in maintaining a properly running engine.

This article will help read sparkplugs and what to look for and what to adjust.

http://www.angelfire.com/fl4/pontiacdude428/Readplugs.html

Mike

 

[RaWarrior]

The right plug looks too rich, and the left one looks too lean. An insulator that is barely discolored from white tends to mean it's too hot.

"Color" on the insulator comes from by-products of combustion...carbon, results of gasoline additives, ect that all burn at different temperatures. Engines are designed to run hot enough to self-clean, to continually burn off deposits as they form. Engines that are too hot will have virtually no deposits, too cold and they don't burn them off. That's largely why engines have thermostats...to keep the coolant temp constant at the ideal range.

The saying for snowmobilers is "they run great just before they blow up"....as in a motor running too lean will seem to be running great and will actually be slightly more powerful, it's also running too hot and before long it toasts rings or puts a hole in the piston. Granted that's with 2 strokes, but it's the same idea.

The a/f screws are primarily for idle to low range operation, but do function throughout the rev range, just the effect diminishes as RPM increases. They're for fine-tuning the mixture, where the jets and needles are your primary adjustments.


For the time being I wouldn't hesitate to run the bike, but avoid prolonged WOT runs. The peashooter/shotgun techniques might not be a bad idea(tutorials are in the VMF Links page). PB Blaster works excellent also, and is much more readily available than aerokroil(which is good stuff too, but around me very difficult to find).

 

[thundermax]

Does anyone think the float may be stuck on the rich burning cylinder?

 

[KJShover]

I downloaded your pics, so I can blow them up for a better look. This was the best I could do, without having them in front of me.
Generally, track plugs are easier to read than a plug that's been in stop and go situations. But, the read is generally the same, just not as accurate as it could be.

We'll start with the left plug;

Ground strap: (Heat Range)
Judging by your ground strap. Your plug seems to be in the correct heat range, if not a little cooler. Generally if the ground strap changes color near the end, it is too cold. the heat is dissipating too quickly. If its color goes all the way to the end where it's attached to the plug, its too hot. and may cause pre-ignition and/or detonation. Ideally the color should be half way down the ground strap.

The base ring (where your threads end, this will show your jetting).
Your A/F mixture is going to show up here. Ideally you would want a light sooty color that goes all the way around the ring. From the looks of the plug, I don't believe this is a lean plug but its tipping on the rich side (The Vmax doesn't mind a mildly lean motor) in fact if the light sooty color goes from about 3/4 to 7/8ths around the ring your probably making the most power. but, we're talking street, not track. so a nice light soot around the ring is what's desired.
On your plug, the wet look, full color that goes around the ring and what appears to be some sooty build up on the ring, indicates a rich plug. Where some people get confused is when there is a complete turn of color on the ring and some buildup, but the porcelain is whiter than Eric Estrada's teeth. This can still be a rich plug.

Which takes us to the porcelain. (detonation and pre-ignition)
The porcelain really doesn't tell, with any great degree of accuracy, the jetting. It does tell of detonation and pre-ignition. You can see on your plug there is some light tanning. I can't see with the picture you posted, but take a magnifying glass and look for black or shiny specs that fused themselves to the porcelain. The black specs are caused from the explosion of detonation. The knocking of detonation is a hell of a shock to the piston, rings and other components. The shiny flakes are little pieces of aluminum that has been broken off and fused to the porcelain.
Also on the center electrode there is a small groove,moat, ditch, or what ever you want to call it. heat range, detonation and pre-ignition will show up here too. Look for melted porcelain to fill up the groove.


The plug on the right;

It's just too bloody wet to get anything off of it.
What is causing this could be a number of things like:

• Plugged air jets
• Float out of adjustment or stuck (sometimes a stuck float will cause fuel to leak, so that would be a good thing to look for too)
• A/F mixture screws out of adjustment

 

[thundermax]

Additives I have been burning: Redline motorcycle fuel system cleaner, fuel stabilizer, RedLine fuel antifreeze. I guess these things will put something on the plug out of the ordinary.