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clean fight
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Discussion Starter · #1 ·
hey guys,
my cbr f4 (carbed) has been getting more and more irritating over the last week.
the bike had been sitting several months untill a couple weeks ago. it worked fine at first but now its getting reallly bad. it had stay-bil while it sat and since then I've run through several full tanks of gas and put on several hundred highway miles .
now its going to crap and im not sure why!

symptoms-

* it doesnt start first try anymore & IT STALLS OUT IF I GIVE IT ANY CHOKE
* it idles rough in an uneven halting rhythm
* & WORST of all - it has started to stumble, lurch, & stall when im pulling away from a light!

(starts right back up again and rides ok until i am pulling from a stop or a very slow corner exit , then it lurches and dies again)


I've done quite a bit of searching and found all different conflicting answers.
If it was a problem with not enough fuel, why would choke kill it?
is it not enough air getting to the fuel?
thanks for the help everybody.
:knucks:
 

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Try dropping the needles down one notch. I had the same problem with my old bike and I did that and it fixed everything
 

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clean fight
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Discussion Starter · #7 ·
sounds reasonable both..
i was just outside now with the airbox open and checking the fuel filter. air filter does look pretty crappy. im on my way to the parts shop now to get carb cleaner, sea foam , and the k&n cleaning stuff because its a k&n filter thats supposed to last forever.( i did clean it last year).
can i start with spraying cleaner into the air intakes with the filter off, or is that wishful thinking? ive never had the carbs apart before. dont have knowledge with this stuff.
 

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The Hell You Say!!
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That's what I was going to suggest...sounds like you've got some gunk built up. Have you tried putting sea foam thru it? When I bought my bike the guy had it sitting with that tank almost empty and ran it out of gas. Clogged up the carbs pretty good. A tank of high octane and sea foam later and it runs great.
 

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clean fight
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Discussion Starter · #10 ·
That's what I was going to suggest...sounds like you've got some gunk built up. Have you tried putting sea foam thru it? When I bought my bike the guy had it sitting with that tank almost empty and ran it out of gas. Clogged up the carbs pretty good. A tank of high octane and sea foam later and it runs great.
ive run through a couple tanks of 91 already and its getting worse.
seafoam within the next few hours... ill find out.
 

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clean fight
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Discussion Starter · #12 ·
dumped most of a can of seafoam in and rode a couple miles to the parts shop.
seems like its a bit better already though it did stutter a bit.
nice folks at the store said not to run carb cleaner through till ive diluted the seafoam by filling up again. aparently it can have bad effects when combined in the carb.
next to clean the air filter...
and a new fuel filter couldnt hurt i bet.
 

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any missfire on startupo? Any greasy black shite in tha muff tip?Poppin when revin up or decelarating?
 

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clean fight
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Discussion Starter · #14 ·
thanks Rob
i will look in the muffler tip tomorrow in the light. its usually always been black with dry sooty residue. no popping or backfiring or anything. off throttle and decelerating with engine braking has always reminded me a bit of the sound of blowing bubbles underwater (i know that sounds weird, but thats what i think of) , a sort of gentle, rolling BUB-BUB-BUB sound. i have no idea if that makes any sense. i had a long day.
 

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post what ya find mate ,we gotta get this fixed for ya;)
 

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clean fight
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Discussion Starter · #16 ·
i cleaned and recharged the air filter and ran it with seafoam and it seemed to come back to working pretty well.
the choke does what its supposed to now instead of killing it.
BUT
i guess theres something wrong with the electrical system now. It started up great with the filter freshened up and i left it idling and after about 15 min it died and had no juice. no start & very little headlight...then no headlight after i hit the starter a couple times.
tried to bump start it and couldn't.
now its got a charger hooked up to it and i removed the new led running light i had put on the tail. maybe that was bleeding juice...
i will go give it a spin later and see what happens.
 

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Vtwin
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Ahhh...weak battery along with gunky carb is a recipe for headaches, I had a Z400 that would start and idle fine until ya touched the throttle then it would cough, pop, choke and die, changed the battery and it was good to go


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clean fight
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Discussion Starter · #18 ·
well, after a couple hours on the charger shes running fine. did a 10 minute spin around the neighborhood..
tomorrow i will try to ride to work and then do the idle test later when i dont need her to transport me anywhere for the rest of the day.
whiplash- youre totally right.
I just replaced the weak battery that wouldn't hold a charge when i brought it out a couple weeks ago. Maybe I was just riding on the original charge and the stator or reg/rec is doing a weak job of keeping the charge up.
found a good troubleshooting guide for charging systems, but it sure is a mess trying to find connectors on the appropriate wires to touch the multimeter and get a reading.
i gues thats something for the long weekend..
 

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Vtwin
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I think when I tested mine it was about 13.8v at idle and went to 14.2 when revved a little, some argue that they don't charge until a certain rpm but mine seems to be charging at idle...maybe its not suppose to but I've never had any problems

Let us know what ya find


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clean fight
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Discussion Starter · #20 ·
Its been a crazy couple weeks of work keeping me busy, but the good news is that the bike got me there and back each time. I sprayed carb cleaner down the throats of the carbs while revving the bike and it seemed to help a bit with power.
but it started stumbling again shortly after i connected back up a cheap led strip runnning light i had wired up to the tail light harness. i guess it was drawing too much electricity or more likely it was just slightly defective ebay chinese crap. unplugging the light and recharging the battery got the bike running alright but the rhythm of the enging still feels a bit messy and uneven and the choke doesnt work again, but its also 100* f outside lately. maybe heat is a factor? other idea is that running on low electric power and missing spark here and there left the plugs or carbs all gunked again?
 
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