Topic: Plug Reading - What may this mean?

[cbass*gxc]

Ok so today I decided to try riding my bike and it kept giving me problems going up hill and whenever I was taking off from a stop.  It decided to die at a main 4 lane intersection this morning so I decided to come back home and play with it for a bit.  I took the plugs out and noticed that 2 & 3 are covered with a shiny black substance with a little bit of stuff on the insulator core and 1 & 4 have a flat black (carbon maybe) build up with fairly clean insulator.  The #4 (right side) has a whitish tan build up on the metal tip. 

http://www.unitedbearing.com/CHAMPIONSPstory.html

They both look normal except 1 & 4 look dry where as 2 & 3 are shiny.

I tried searching and didnt seem to find the answer so I was hoping you all could help.

[Gordon]

Shiny black as in oil fouled?

[cbass*gxc]

Here is what they look like. I wouldnt say oil fouled because there is not much build up.  It just looks shiny.   They are in order from left to right.  And the second # is the temp of each exhaust after about 5 minutes of "trying" to start it.  I decided to recheck the tappets and timing and noticed the timing was off, so I checked all the ignition systems and timing to make sure everything was ok.  Now when I try to start it, it doesnt start unless I give it gas and then when I do it barely runs then revs real high, so I let off the gas and it bogs down and dies.

Here is a link to a bigger picture.  http://jaypage.com/pics/motorcycle/Plugs.JPG


A little while after I got back I decided to check the pilot screws and noticed they were twisted out quite a ways so I turned them back in and then out 1 and a half turns and that is when it seemed to stop firing on all cylinders.

[jtrain]

carbs?

[333]

Are you checking the tappets when the engine is absolutely cold?   #4's color looks correct, but the temp says it's not firing at all.  #1 looks like it's running rich.  Besides the carbs, here's some other things to check.

1. Check the spark plug caps.  They "screw" on to the wires and sometimes corrosion builds up in there.  This could be the answer for #4.
2. Do a compression  check(after making sure the tappets are correct when cold).
3. Check the intake manifolds (between the carbs and head) for leaks.

I'm curious, how are you checking the temp?

[Jerry Rxman Griffin aka MuthaF'er]

When you check the plug caps you should use your ohm meter and check & compare the resistance across them too. Wanna make sure the current gets to the plug. When you reinstall or use replacement caps cut off the ends of the plug wires and reinsert onto the caps provided you have enough length. I picked up a blaster spark plug cleaner from Harbor Freight for less than $10. Real handy in situations like yours so you don't have to buy a box of spark plugs. Just make darn sure they get blown out and rinsed with solvent before reinstalling.

Can someone load that spark plug chart into FAQ section?!

[cbass*gxc]

333 - I have checked the plug caps a handful of times and cleaned the connectors.  I am getting spark from all 4 plugs.
I will check the compression tomorrow and the intake manifolds.  I am using this Infrared Temp Gauge.

Rxman - The resistance is the smae on all four.

[eurban]

What are you pointing your IR gauge at?  Chrome?  Those IR gauges cannot take a proper reading from a shiny surface like chrome. Readings will be all over the place!  Will work well on flat black exhaust pipes. . . .  What bike? How long since you properly went over the carbs?  Condition of points plate components?  Do you get bluish smoke while the engine is running?

Those plug charts are fine and dandy for assessing the overall condition of the bikes combustion.  Like after a couple of hundred miles of riding or so (more quickly if problems are severe)  However people mistakenly think that they will observe instantaneous changes in the appearance of their plugs (like from one chart PIC to another) after they tweak carb settings, change jets etc. Sooty plugs will not miraculously clean themselves (at least with our antiquated ignitions).  Plug chops, for instance, should be done with brand new plugs and your if plugs look like any of those in the charts after one or two runs then you have some very serious problems!.  Reading your plugs after a plug chop is a much more subtle affair . . . End of somewhat OT rant.

[cbass*gxc]

Actually my exhaust has been grinded so that I can paint them.  Even if they jump all over the place they arent going to jump around a couple 100 degrees.  It is a 78cb550 and the carbs were just cleaned a few months ago.  My points plate seems to be just fine.  I was getting a little bit of whitish/blue smoke out the left side.


As far as the plugs that is the way they look after about an hours total use.  I bought brand new plugs and like I said they have only been used for an hour or so.

[TwoTired]

You might wish to look here:
http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html

Are your exhaust headers the stock double wall pipes?  The way they are bent during manufacture, there is no guarantee that the inner makes full contact with the outer.  In fact, that's kinda the point for double wall exhaust in the first place.

What was the ambient temp during the readings and was there a fan blowing on the motor? How long was the engine running, and was the choke off fully on all carbs?
What air filter are you using?  Pods? If so, are they oiled equally?
Did you do a sanity check on the IR instrument and compare the pipe heat by flash touching the pipe?  Did you measure the same relative point on each pipe?  Were the readings consistent 5 inches away from your previous readings?
Did you double/ripple check instrument readings for consistency?

If spark timing, cylinder compression, valve adjustments, are all good and equal.  Then that leaves carburation as the issue.  Intake runner leaks aside, are all the carb adjustments equal?

Did you just rebuild the motor?  New rings?  Valves?  What mileage on these parts?

[754]

Throw the heatgun away and learn to troubleshoot..

[eurban]

Even if they jump all over the place they arent going to jump around a couple 100 degrees.

My experience is with shiny chrome stock type pipes.   The IR meter will give inconsistent readings when pointed at the chrome headers.  The instructions for my Raytek mention this issue.  I can't say what the range of inconsistency is but your numbers aren't consistent with what your spark plugs are telling you so I would guess that something about your "test" technique is off.  The proper mix for idle and off idle is on the rich side.  If you let your bike idle for prolonged periods of time you will get sooty looking plugs.  As I mentioned the plugs can be properly compared to those charts (Dansmc included) only after a long ride, not after prolonged idling or after a cold start.  You plugs sure look inconsistent.  Something is certainly amiss. . . .

[754]

I have checked my plugs as often as 2 times or more in a mile.. Where are you guys getting this has to run for a while theory??

 To me the most important is that it actually gets stopped at the range you are checking.and you actually learn what you are looking at..

[eurban]

754, did you actually look at the plug chart links mentioned in this post?  They are for comparing plugs to that have been used for a good number of miles.  You say yourself that you have to know what to look for.  What do you look for?. . . . .A new plug used for a single plug chop on a perfectly tuned motor will in no way resemble the tan "perfect" plug.  But yes it will give you very good information if you know what signs to look for.

[754]

Actually I did not view any of the links.

I should have explained that plugreading is a bit difficult at first and perhaps confusing.

I often see or hear of people trying to read their mainjets, but letting the bike idle or downshift before checking plugs.. no wonder they have trouble.

So lets just cut to the crux of the problem, and keep it basic.

If the compression is fairly close in all cylinders, then the one cylinder clearly has a problem that seems to be something between the coil wire outlet and the carb...

So lets work on that .

[cbass*gxc]

TT
They were stock 4 into 4's but I have cut the mufflers off and it looks as though it is only 1 wall.
The garage was about 65 and there was no fan.  They got that hot just from trying to start the SOB.  And I did as you said and used the factory airbox.
I did a few test to see about temp and they seemed to be close. 
Yes I measured the temp from the first down bend on all 4 pipes.
I rebuilt the top end of the motor with new pistons, rings, and valves.  The original mileage was 15k.

Eurban
May pipes have been sanded rough so the paint will stick better not to mention there is some rust on them.
I have let the bike idle for quite a while the past few days.  It takes it a little bit to get warmed up and idle on its own.

So as far as doing plug test do I need to use new plugs for each test or can I use the same ones?  I wish someone lived closer who could help me out.

[cbass*gxc]

Well I dont know exactly what I did but something has changed.  I think it was the timing itself because one of the screws was loose when I re did the timing and now it runs like a champ.  I tried starting it again this afternoon and it fired right up and seemed to run pretty good.  She stayed idling even when I took the choke off.  So I decided to go around the block and see how it ran and it had plenty of power going up a hill and starting from stop.  I decided to ride it around the neighbor hood for about 30 minutes and it ran great the whole time.  I am going to check the plugs again after the engine cools off a bit.  I will post a pic of what I find.

Jay

[333]

When was the last time the carbs were synced?  This will also give you the uneven readings, especially with long periods of idling.