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Discussion Starter · #1 ·
ok I have a 2002 v stat 1100 and after about 30 miles it fouls the plugs, I have been through the carbs 3 times cant find any thing wrong, bike has had long shot pipes on it since new, jets are 110 in the front and 12.5 in rear witch are stock jets, it acts like the plugs are not firing hot enough, going to check the voltage regulator and stator today, has anyone ran into this before, I am 99% sure it is electrical and not fuel, any help would be great
 

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It's not that unusual for a bad ignition coil to cause the problem you're seeing. The output tends to go down as they warm up, usually about 20 or 30 minutes. And everything will be fine again once it cools back down...for another 20 or 30 minutes.

I'm not sure how your charging system would be suspect unless your battery is also draining and/or going dead. While you're in there checking that out, you might as well check and make sure your grounds are all gütentight.
 

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Discussion Starter · #3 ·
plugs

the stator is putting out good ac voltage but when I check voltage at the battery I have 13.8 at idle and 13.6 when I rev it up to around 3500, so not sure if I have a regulator problem or igniter problem, I was thinking coils but both plugs will foul, I guess there could be a problem with both coils but what are the chances of that
 

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plugs

Hi mate this might be able to be done or not but if you want to check if it is the coil chnage them around ,you know which plug is foulng now connect the lead from that cylinder to the other if it fouls you know its the coil .
 

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plugs

Hi mate well this is a bit of a tricky one ,you have the correct heat range plugs i imagine as your not silly ,i am tending to think it may be fuel or something more sinister as unless both your coils are stuffed only one plug should foul at a time but it may still be the but it is a long shot.The other thing is have you checked your compression ,are the plugs oily when you take them out or just dry carbon ,if your compression is down it may be a worn or broken ring but we really dont want to go down that track yet .Have you been mucking about with the carbs as nick57 has said if your jets are around the wrong way maybe this is the problem ,these are only suggestions mate but keep us informed as what you do .
 

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Discussion Starter · #9 ·
fouling plugs

both plugs are black and sooty, it has the right plugs an jets the bike ran great for 21000 miles it was parked for the winter and when spring came around is when it started, I have been through the carbs 3 times, was thinking electrical so the stator and regulator both check good, next I was going to ohm the coils
 

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plugs

Hi mate this might sound a bit dumb but you said you had it parked for the winter ,did you use any form of stabilizer in your fuel or did you drain the tank ? Regular startup can help but wont stop the fuel from degrading ,Fuel here has a life expectancy of around three months before it starts to degrade ,mixing new fuel with old is not a good idea either ,check your coils but i would find it unusual that they both go at the same time but you never know . Check all your wiring connections just in case one has come loose or some fury creature might have wanted to have a fang on it et us know what you find .:)
 

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i dont want to keep harping on about fuel mixture but this spring i had one plug black and sooty and what i found was the threads on the pms screw were dirty and when i turned the screw all the way in it would not go all the way in.so when i backed it out the three turns for my bike i was actually out 4 turns.when the screws are all the way turned in you can feel them sticking thru in the venturie
 

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I have a 2004 v star 1100 doing the same thing fouling the plugs. Souty, one plugs was going first. Now both are fouled, bike misfiring. Let it set a week after taking it out runs a lot of fun.

only misfires when under a load.
Please help!
 

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2003 RS Warrior S*2-1-2(G2). -AIS. VBAK/K&N(RC1290). CobraCVT. Ivans. SR-2. DC2-1.
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Suggest replace the needle and seat in carburetors. Use actual Yamaha parts. While open anyway you might find a bad float, if affordable get those too. These are fairly common culprits.

[stupid suggestion deleted, my bad]
 

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Suggest replace the needle and seat in carburetors. Use actual Yamaha parts. While open anyway you might find a bad float, if affordable get those too. These are fairly common culprits.

You might check the fuel pressure regulator to be sure the atmosphere port nipple does NOT have a vacuum hose on it.
Does the 1100 have a pressure regulator? Never thought about it but it makes sense.
 

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2003 RS Warrior S*2-1-2(G2). -AIS. VBAK/K&N(RC1290). CobraCVT. Ivans. SR-2. DC2-1.
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@Deeksvstarclassic

You are right, I should not have suggested FPR ambient tube block.

This bike's after-the-pump fuel pressure is regulated differently, it's a diaphram/spring fuel fill setup. My apology. Good catch!
 

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been running 6" baffles in my cobra longs these kind i can wrap,I would say i've lost some top end, performance exhaust is straight thru. .my plugs are tan, before they were white, and on decell i could adjust the pms to get popping on decell. I've been turning my screws in every couple weeks to get the plugs lighter and increase fuel mpg. yesterday i think i'm getting a little popping. i'm running 20 pilots and thinking about going to 17.5 and turning the screws out a little.. with the 17.5 i think the screw adjustment will have more responce. i was hitting reserve at 135 now i'm at 120. on a side note i'm running pms screws out of a 650. the tapers different.
 
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