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Ok I'm new here. I have a 03 Duece. The problem is misfiring at constant speeds. At first, I thought I had gotten some bad gas so I drained the tank and filled it with fresh gas. But, no change. I have tried new plugs, and tried different plug wires off of a friends Duece. But, the problem is still there. I can roll the throttle and it runs like a champ. At constant speeds there is still a misfire. I need some input on this problem.
 

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Ok I'm new here. I have a 03 Duece. The problem is misfiring at constant speeds. At first, I thought I had gotten some bad gas so I drained the tank and filled it with fresh gas. But, no change. I have tried new plugs, and tried different plug wires off of a friends Duece. But, the problem is still there. I can roll the throttle and it runs like a champ. At constant speeds there is still a misfire. I need some input on this problem.
Fuel Injection or carb ??
Any fuel control/tuning ??

A little more information if you will please . :)
 

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Typical symptom of leaking intake seals.
With the engine idling squirt some WD-40 around the intake manifold to head joints. If the idle gets erratic or the engine wants to stall the seals are leaking and need to be replaced.
Be careful to not get any spray into the back of the air cleaner or that'll fudge the test.
 

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Ok I'm new here. I have a 03 Duece. The problem is misfiring at constant speeds. At first, I thought I had gotten some bad gas so I drained the tank and filled it with fresh gas. But, no change. I have tried new plugs, and tried different plug wires off of a friends Duece. But, the problem is still there. I can roll the throttle and it runs like a champ. At constant speeds there is still a misfire. I need some input on this problem.
If this misfire is what many others will refer sometimes as a hiccup then SCHMIDTYS post is what you need to do.:nod
 

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Discussion Starter #5
It is fuel injection. I have a service and repair manual for it and tried some things that it said to check but found nothing yet. If it would set a code it may help me out a little. No fuel/control tuning. I am not one to give up but this is testing my patience. Not sure if its the fire or the fuel.
 

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Discussion Starter #6
Its not a hiccup. I can be cruising about 45 to about 65 in high gear with a constant throttle and you can feel it misfiring. I refuse to give up.
 

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Discussion Starter #8
Yes I did. But no change. Pulled the tank earlier to look for something obvious but nothing jumped out at me. I did pull the air filter and cranked the bike. Held it at a constant throttle and when it misfired you could see it ignite behind the butterfly. Like its loading up with fuel then igniting. I need all the help I can get.
 

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Being a EFI machine could be nothing more than a tuning issue. Any changes to the exhaust or intake. If yes then a dyno tune may be in order.
 

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Discussion Starter #10
No sir. No changes. It is giving me a fit though. What ever it is it is affecting both cylinders. Cranked it in my shop with the lights off to see if I could see any fire jumping. When it misfires a small blue flame comes from both exhaust.
 

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Yes I did. But no change. Pulled the tank earlier to look for something obvious but nothing jumped out at me. I did pull the air filter and cranked the bike. Held it at a constant throttle and when it misfired you could see it ignite behind the butterfly. Like its loading up with fuel then igniting. I need all the help I can get.
If you can see it ignite inside the throttle body you might have a valve sticking a little.
 

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You didn't say how many miles are on the engine.
Has the cam plate been serviced yet ?
No DTCs (codes) ?
 

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Discussion Starter #13
To whom it may concern. I found the problem. The fuel line in the tank between the fuel pump and the quick disconnect had a pin hole in it. I was loosing fuel pressure to the injectors. Replaced the line and back on the road again. Thanks for every ones input.
Lets Ride
 

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Discussion Starter #14
To whom it may concern. I found the problem. The fuel line in the tank between the fuel pump and the quick disconnect had a pin hole in it. I was loosing fuel pressure to my injectors. Changed the hose and back on the road again. Thanks for every ones input.
Lets Ride
 

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Good info for us all to learn from. Thanks for posting the cause you found!
 

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Discussion Starter #16
I found the problem. Pin hole in the gas line inside the tank. Loosing fuel pressure. Thanks for every ones input.
 

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Discussion Starter #17
I found the problem. Pin hole in the fuel line inside the tank. The line between the fuel pump and the quick disconnect. Loosing fuel pressure to the injectors. Replaced the line. Running like a champ and back on the road again. Thanks for every ones input.
Lets Ride.
 
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