One more update... today, after having well shaked the tank with bolts and screw i added the vinegar and let it sits... so i was bored and thought about checking the spark plug, just in case... i have installed a brand new one when i changed oil and filters so i was almost sure that it would be ok... WRONG!
From what i've read on internet it could ba a symptom of running rich...
Is it right?



Anyway, tomorrow i put the bike back together, put a fuel filter between the petcock and the carb and see what happens

WD wrote on 04/06/13 at 16:38:11:


Ok, Thanks. But the "fun" part it's that this one has maybe less then 10 miles, i never ridden really the bike, just couple of rounds once in a wile around my block (it wasn't insured) just to let the engine run a bit and let the new oil flow.
Also, this is the spark plug indicated in the owners manual, the NGK DPR8EA-9... Anyway, tomorrow i try to turn it on and see what happens...
Thanks to You guys i'v been able to narrow down and tackle a bunch of problems that this bike came with...

maxtowers wrote on 04/06/13 at 10:57:55:


You need to get the bike warm and ride around before ou take a plug reading.  I will look around and see if I can find a link for taking plug readings....rather than type it all here.

I would use some Anti-Sieze on the plug.  The thing  you don't want to have happen is the aluminum adhering to the spark plug.

You can go for a ride, get the engine warm and ride as you normally would...and you will get a genral idea if you engine is running rich or lean.  But if you let it idle too long then the only plug reading information you will get is what happens at idle.

Here is a link for how to jet a CV carb:
http://www.zrxoa.org/webpages/techinfo/carb/carbtuning.html

Here is a link for reading spark plugs.  The second paragraph explains how to properly get a plug reading.....then what to look for:
http://www.jetsrus.com/FAQs/FAQ_spark_plugs.htm

Ok, here's a short update on how things are goin'...
I cleaned the tank and made one of those treatment on the inside of the tank, cleaned in the meantime the carb, changed the bowl gasket that was broken,put a filter between the petcock and the carb, and after a week (the time to allow the epoxy inside the tank to harden properly as the manufacturer specify) and put all back together and voilà, the bike runned fine for a couple of days... Awesome if it wasn't for today, that after a short trip to a friend of mine home that son of a gun won't start...
Now i've disassembled it again, drained the tank to check the treatment, and i will check the spark plug, because from the symptoms seemed that there were no spark or at least not enough to ignite the gas in the cylinder.
BTW those two days were beautiful, the bike seemed running fine apart for a tickling in the right side of the engine, so i thought to check the chain tensioner (the bike tachometer reads 12.765Km, about 7930ml. if they are real...)
I will keep you posted.
Have a good weekend Everybody.

Mine has run a 5 for about the last 6 years. A lot of commuting from the mountains down to sea level in the city for work when I lived on the west coast. Anything colder would foul out in a month or less. 3 hours to go 36 miles wasn't unusual.

I wouldn't run a plug that was too hot for the engine. If your plug is fouling, you have a way too rich carb or blow by from worn rings. Fixing them would be the proper solution.

http://www.xtrememotorworks.com/Spark%20Plugs.htm

The worst result of a too-hot plug that fails-to destroy itself, is when it destroys the engine instead; this is called pre-ignition. If the tip of the plug becomes hot enough to ignite the fresh mixture being drawn into the cylinder, then the incoming mixture will start to burn without waiting for the spark to happen.

Ignition due to any hot spot in the cylinder begins before the proper time for ignition, so it is called pre-ignition. Anything in the combustion chamber which gets hot enough can cause pre-ignition, but typically the end of the spark plug is the cause. When the mixture is firing sooner than it should, that's like advancing the spark too much, and no matter what causes it, early ignition makes engines heat up, causing pre-ignition. Eventually, something melts, which comes under the heading of a bad thing.

A friend suggested that maybe could be the muffler obstructed by residue since probably it has never been cleaned... is it realistic? He suggested to run for a while without the muffler or with one less restricted and see what happens in the span of about 50 miles that is the average that i had between needing to pull the spark plug and clean it.
I live along the west coast, litterally few hundred yards from the beach, and usually not climbing big mountians... so better to go back to the old spark plug and see what other thing might goin' on?
In this case i guess i'm gonna take it to a mechanic, goin' around cylinder, piston and all that stuff makes me uncomfortable doin' it by myself with no experience in doing so...
Do i have to stop running it or can i use it anyway?
Sorry for all this questions, but apache snow kinda scared me a bit...