Replacement engine question, carb cleaning necessary?

[chidarste]

Hey all, I'm trying to figure out why my bike is jacked up.  It's a long sordid history of a learning lesson between me and my gs500f.  I have a 2007 model and wasn't very nice to it.  So now I am trying to replace the blown engine with a working version.  I replaced the engine and fired it up but now unfortunately it is beginning to misfire.  The spark plugs initially were a fine light brown color, nothing I would think was a problem.  It took a little bit of time after replacing the engine for the spark plugs to change color, and I got pics of the outcome.




Story goes, I sat the bike + tank + fairings outside while the vital components (airbox, carbs, screws) went into a non-airtight storage unit.  I did not drain the carbs prior to storage.  After replacing the engine and piecing everything together and spraying carb cleaner and running seafoam rich mixture through, the engine started up and began purring *somewhat*.  However, right now there seems to be an issue where the motorcycle misfires and I hear the painful noise of a piston complaining.  I pulled the spark plugs (as shown above) which had a carbon film and replaced them with the original spark plugs but the problem persisted (pics of original spark plugs upon request).  This really is the first foray into in-depth motorcycle maintenance or really any engine work of any kind and the service manual has been helpful but I fear comes up short in this instance.

I've read the forums and am beginning to suspect that the battery may be a little low, however hearing those pistons whine is not a happy noise where I'd be willing to test it.  So, my question really is:  what all could this be?  I really think having the carbs sit for a year is worth a cleaning.  It's a toss-up whether to learn it myself or pay someone else to do it, as I'd like to eventually migrate to a larger fuel injected vehicle.  I do like learning tho

Apologies for being long-winded even though there are alot of details I left out in the destruction/reconstruction process.  I just want to get my bike up and running again.   

Thoughts/ideas/suggestions/commentary/censure?  I would like to hear it all.....

-dan

[Big Rich]

Yep, the carbs really should be cleaned. However, black plugs point to a different problem. Is your air filter clogged? Make sure your battery is fully charged, plugs are gapped properly, valves are shimmed to spec, and get the carbs scrubbed.

If you still have a problem......well you have a real problem.

[Pelikan]

Hey man, i'm far from an expert when it comes to this stuff, but this link might help you diagnose the problem: 

http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html