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Author Topic: Stumble,power loss when applying throttle  (Read 1064 times)

seth-kiki

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Stumble,power loss when applying throttle
« on: April 20, 2008, 04:55:48 PM »
Hello,
      I have a 2007Bullet. I love it. Last summer it developed what I would describe as a stumble when accelerating from a standstill. The engine idles fine. The problem got worse and worse. I pulled the plug and it was fouled. It seems to have been running too rich. I adjusted the carb and the bike ran great for the rest of the summer (approx 500miles).
      I pulled out the bike last week and everything was great but the problem came back just like last time after about 50 miles. I have not changed the spark plug this year yet. It seems to happen when about 1/4 throttle is applied. There was no old gas left in the tank when I put it away and it has a full tank now. Could it be running to rich again?

fredgold52

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Re: Stumble,power loss when applying throttle
« Reply #1 on: April 20, 2008, 05:35:03 PM »
Can you describe how your engine is set up?  Things like air filter, exhaust, pilot jet, main jet, needle clip position would be helpful. 

My first reaction to how you described the problem was that it was too lean.  If the main jet is too small, or the needle is set too lean, the engine will starve for fuel when the throttle is openned.  But you say you fixed a similar problem last year by leaning it out.  Thats' why I asked for the set up information.  It would help in diagnosing what's going on in there.
2006 '65' and a 200cc Stella, Indian all the way

seth-kiki

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Re: Stumble,power loss when applying throttle
« Reply #2 on: April 20, 2008, 06:55:28 PM »
Thanks for writing back so soon. I have left everything on the bike completely stock. I haven't touched the exhaust or air filter. I haven't changed jets or the needle clip position.

mtrude

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Re: Stumble,power loss when applying throttle
« Reply #3 on: April 20, 2008, 10:55:00 PM »
Hello for what it is worth I recently had a similiar problem on my 99 bullet. The engine would start, but the run poorly just off of idle, in checking the carb I pulled the drain plug to look for water in the float bowl, no water, but very little fuel when I turned on the tap. It turned out that the petcock was clogged with grit and red paint chips. The inline filter was doing its job but didnt have much fuel to work with. It may be the exact fix for you, but its something else to look at. good luck, have fun, mtrude

fredgold52

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Re: Stumble,power loss when applying throttle
« Reply #4 on: April 21, 2008, 03:47:10 PM »
I agree with mtrude.  It sounds as though it's starving for fuel right at the point it's transitioning off the low speed jet to the needle jet.  My first choice would be to clean the low speed jet and the two passageways the fuel from that jet follows.
2006 '65' and a 200cc Stella, Indian all the way