Bonneville America Forums Forums Technical Forums General Tech rejetting new pipes.

trying to figure out how to get my bike back to running properly. got the proper pods and used the jet calculater but still backfiring and now the carbs cut out back and forth . i dont' know what to do now . can someone please assist?

Check for leaks at the carb to head connections and be sure the rubbers are on the right way.Make sure the vacuum caps are on the nipples too.

Air injection still installed on your bike?, have you also tried disconnecting the "throttle position sensor", are your carbs balanced? Have you adjusted the "D" screws underneath your carbs. Etc,etc, fill in the blanks and we will get you plumbed up.

Give us a complete account of the work you have done on this bike. include year model and milage. because your carbs could be out of balance, the valves could be out of adjustment, timing could be off, pick up coil could be gapped wrong, you could have a leak sucking air in.

my bike is a 2002 tba with 4879 miles on it. I used the Dinqua instructions for changing the jets. the jets jets are now 150 's , size determined by the Dinqua/Friar jet calculator. The pipes are Epco's. I have K&N pods on therein place of the air box. I believe the throttle position sensor is disconnected,if it is the one sort of shaped like a "t". I don't know what the air injection is, the nipples are capped,the carb head connections seem solid,I haven't messed with the D scews but I did drill out the tamper plugs so I do have access. As far as the carbs being balanced they were fine before so I don't really know how I would have unbalanced them. I have limited experience with my old Triumphs ,(they break, I fix= experience) I'm no motorcycle mechanic but I kind of know what I'm doing and can figure things out , maybe after a few tries, but mostly successful. Appreciate any more help anyone could give.

Maybe I'm the only one but could you describe the symptoms a litle more. "Carbs cutting out back and forth..and backfiring." when does this occur at idle 1/4 1/2 3/4 WOT. Does it backfire and cut out or pop as you let off the throttle? Does it do it underload or just on the stand? Did you change the pilots?
The AI will be a metal tube next to your spark plugs, if it's still installed. But it doesn't make a performance difference.

You stated that the throttle position sensor was disconnected. How? Was it unplugged at the connector between the carbs or unscrewed from the carb body ("T" shaped"? If it was simply unscrewed and left to hang there your engine will not run properly since the sensor is still sending a signal that the throttle is in one position even when the throttle moves.

I was just able to spend a few minutes in the garage. I was able to snug the carbs tighter to the head do to the fact that my carb bracket was holding them away a 1/4 inch or so, there were telltale dust marks. It seems to be getting too much fuel. Backfires throughout throttle range , pretty randomly, and also when I let off but not immediately, takes a few seconds then backfires. does this mean I need to mess with the "d" screws underneath. At one point, prior to tonight, I twisted that knurled knob that bends up to the carbs but it didn't seem to make much difference. As far as the "t" shaped clip goes , I was looking at the wrong one. I didn't check it under load just on the stand (tomorrow hopefully). I did not change the pilot jets . The carbs don't seem to be cutting back and forth anymore since snugging them up. Again, I appreciate all the input , hope I'm being specific enough.

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I twisted that knurled knob that bends up to the carbs but it didn't seem to make much difference.

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That's the idle adjustment. Left slows it down, right speeds it up.

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As far as the "t" shaped clip goes , I was looking at the wrong one.

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Greg was asking how the TPS was disconnected. Was it unplugged at a plug between the carbs, or was it removed from the outside of the right hand carb?

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The carbs don't seem to be cutting back and forth anymore since snugging them up.

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Snugging the carbs up should make a world of difference. If you had air leaking between the carbs and manifolds that would cause backfiring on decel especially. Also check all 4 rubber vacuum covers for integrity. Air might be leaking there too.

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It seems to be getting too much fuel.

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Pulling the plugs and examining their colour can tell a lot about lean vs. rich conditions.

That knurled knob is your idle adjustment-on left side of bike. One thing to check is to make sure your rubber intakes are on right side up if you took them off. There is a pic in the tech vault.
TPS is located on right side of the bike.
150 mains with epco and pods sounds about right without looking at the calculators. If you turn the D screw all the way in counting the turns (I put a black mark on the tool to count the turns) then turn it back out. Start with 2 turns and kind of play from there. Both sides obviously. It's a good easy and free place to start.
Hope that helps some.

When you had the carbs off did you separate them?

put the stock pipes back on and report results.