New defelopment... cold cylinder

I changed my plugs today and discovered my right rear plug had a white powdery buildup on it. Once the plugs were changed and the bike was warmed up to operating temp I dsicovered that that same cylinder is cold... well not blazing hot like the other three.

Obviously you can't touch the exaust headers coming out of the engine, but that right rear one I can wrap my hand around and not get burned...

Possible causes are what?

Chip

 

would check for spark first, pull the wire and crank it with the plug removed and grounded
if you have spark, would look for a carb issue

 

OOOOORRRRRRR i'm just a big fat retard and didn't plug that cylinder back in when i put the new plug in... I won't say for sure which one it was though.

 

http://vfrworld.com/forums/specifications/3161-downloadable-parts-catalogs-service-manuals.html

click da link and download a manual and test the coil ( or whatever they call it now ) on that cylinder.
another option would be to change it with another one and see if that one ends up cold

 

:redface::censored::tape::tape::tape::tape::tape::tape::tape::tape::tape::tape::tape::tape::tape::tape::tape::tape:

 

It would not be nice for me to agree with you about being a big fat retard. LOL. Good to see people have fun with their mistakes.

 

I am with randy on this one....I could call you that cause I have never laid eyes on you...there for it would purely be speculation and conjecture as to you really being a "big fat retard"

at least you found out hte problem fairly quickly

 

so please let us know what kind of mileage you are getting now

 

In my IT dept we call that "working as designed".

 

I May be wrong but the plug and header should get hot to the touch even if that cylinder isn't firing. The energy created from compression alone is enough to get it up to a few hundred degrees. Diesel engines keep firing just from the compression energy, hence the term "dieseling". If you don't believe me clap your hands together a few times and you can feel the heat build up in your palms. After a spark test I would check the compression, it's way easier than tearing apart the carbs. If the compression is low shine a flashlight into the spark plug hole and see if you've burnt a hole in the piston crown.

 

That'll do it every time.

 

I assume he had only run it a few min, and the above would take several minutes to get it hot.

 

Semantics... He said he warmed it up to "operating temperature"... that's the point just before or right after the radiator fan cycles, at least in automotive circles it is. With my bike that would take five to ten minutes of idling and occasional throttle blips. If he meant he warmed it up to where he didn't need the choke on anymore, that's not really "operating temperature". At operating temperature that plug should be hot to the touch even if it weren't firing, not skin melting hot but hot enough to make you not want to touch it again.

When I do a compression test I usually do one "cold" and one after the radiator fan cycles at least once, you'd be surprised how different the #'s can be from cold to warm. Comparing the results from the two tests can give you a clue as to whether the problem is in the rings, valves, head gasket, or even a crack somewhere. The same goes for testing the spark, I've had coils that were fine when cold but after they got warm they would fail... And a weird scenario where the brand new recommended NGK plugs for two-stroke Suzuki twin would fail 50% of the time after warming up, switched to Champions and the problem never came back. My long winded point is... engine temperature can be a very important factor when conducting diagnostics, just so you don't end up chasing your tail.

 

It was fan on full operating temp..

Regardless it was my own stupidity in overlooking hooking the connector back onto the boot that cause the dead cylinder.

I'm just happy that's all it was.

 

I thought you were kidding about that... I did that ONCE with an old Wet Bike on a test drive, didn't put the boot all the way on & it popped off when I was in the middle of the lake. Didn't make it back to shore till way after dark, I can't remember being more pissed at myself than when I figured that one out. It even cost me a girlfriend, she didn't buy my excuse when I stood her up.

 

I wish I was kidding about it... I'm just happy I found it before tearing into anything trying to fix it.

As for the GF that left you because of that.. IMO you're probably better off if she was that unreasonable.

 

Back in my 2-stroke days we thought the Champions were crap and only NGK were good, but your point is fine: Honda service manual specifies hot compression at about 180-195 psi so tests there are most relevant, cold, who knows ??

BUt you're right that coils (pick up or ignition ) caN be fine when cold but fail when hot if they fail, when they fail.