problem / pics of plugs / opinion?

[ghostntheshell]

1.) New plugs. Carbs synched after install.

2.) Loss of power, exhaust pop, stumble/ miss.

3.) Tightened exhaust up already, did peashooter.



Pulled 4 plugs...

ONE plug was all black and wet with what smelled like gasoline. It did not appear to be oil.

The other three plugs looked identical.




What does this one black / wet with gas plug tell me?

 

[maleko89]

Is that plug wire firing?

 

[06VMAXIMUS]

Wet=no spark/weak spark.

 

[gamorg02]

1.) New plugs. Carbs synched after install.

2.) Loss of power, exhaust pop, stumble/ miss.

3.) Tightened exhaust up already, did peashooter.



Pulled 4 plugs...

ONE plug was all black and wet with what smelled like gasoline. It did not appear to be oil.

The other three plugs looked identical.

View attachment 14980View attachment 14981


What does this one black / wet with gas plug tell me?

possible bad plug? try putting another one in?

 

[ghostntheshell]

How can I tell? I would assume cause it's covered in black carbon it is...

 

[davidon]

Try putting the old ones back and see if it still does it

 

[06VMAXIMUS]

How can I tell? I would assume cause it's covered in black carbon it is...

You said it was wet with fuel. You can buy a spark tester that you lay on the wire while the bike is running, and it will show if it is sparking or not.

 

[ghostntheshell]

I thought about that but I can't find where I put them. I have a NEW new set. I will gap them and try that I guess.

 

[woodsman30]

to me it looks like the gaps are different on those plugs are they the same? make sure they are this will effect spark more than you relies. Different gaps means different rates of heat on each plug also different spark. start fresh with new plugs and gap to specs
that's where I would start first.

 

[EAGLEPI]

What should the gap be set at ?

 

[woodsman30]

most plugs are .030 depends on the heat of the plug shorter the gap the hotter the spark but I always set at .030 never had a problem ever.

 

[maleko89]

Remove plug, reinsert in boot....set on top of valve cover so it is grounded. Turn the engine over and look for a nice, blue spark.

 

[gamorg02]

or if you didn't have any other plugs, swap plugs for cylinders and see if the problem follows after mark's test.

 

[tugla]

another way is with all plugs installed run the bike and either use a digital heat gun on each header in roughly the same spot to get a reading or if you dont have one do what i do and splash a little water off your fingers onto them. now pay attention to the rate of how fast the water evaporates off the pipes. sometimes even if its a weak spark you will get a little heat so water goes away but if you notice a difference on how fast compared to the others then for sure there is a plug/wire/ carb issue on that cylinder.

 

[ghostntheshell]

I did check header heat.

The black wet header wasn't cold - but it was colder for sure.

What gap size? My haynes manual says 0.8 - 0.9mm.

Must have not been weak spark...


Next question is why?

 

[ghostntheshell]

SO let me get this straight... install plug into wire. Place plug on valve cover - and start engine and observe for spark?

I have them all gaped in between .8-.9mms.

 

[gamorg02]

SO let me get this straight... install plug into wire. Place plug on valve cover - and start engine and observe for spark?

I have them all gaped in between .8-.9mms.

yep. make sure its not the plug too. if u don't see spark, try a different spark plug there and see if it sparks.

 

[sidwin]

bad coil pack or RR. move the coil pack and see if the problem follows.

 

[Thevmaxrider]

If you don't know how old the plug wires are I would consider changing them, or at a minimum trim the ends about 1/8". They corrode and loose conductivity.

 

[ghostntheshell]

UPDATE:

1.) Trimmed spark plug boot a sliver to ensure it is seated.
2.) Re-installed all plugs
3.) Checked for spark (grounded on valve covers) nice, solid blue spark.

Took it for a test ride.

STILL snap crackle and popping until about 4k rpm.

STILL stumbling and sounding the crap.

Looked at problem plug - dry and no black carbon.