whats causing backfiring?

[dirtyd]

I'm getting fustrated. Since last summer my R hasn't been running right in the middle. Starts and idles fine but when giving it throttle it starts to stumble before coming onto the pipe and sometime back fires and once it runs on the main it runs good. Iv'e got  38mm A/S DGH needle and tried every position, 48 pilot 180 main. Fresh gas 50/50 mix race and premium. I am wondering if its electrical like maybe the coil. I swapped out stators and cdi (all OEM) and new spark plug wire. I didn't have a spare coil so thats my last hope maybe unless you think its jetting. Any help would be great.

[Victork]

Did you do a plug chop?

[udontknowme]

back firing seems like it would be caused by a premature spark. malfunctioning cdi maybe

[dirtyd]

Tried a couple cdi's and stators with same result. Was thinking coil but someone was telling me they thought a coil works or it doesnt, is this true?

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[Jerry Hall]

I'm getting fustrated. Since last summer my R hasn't been running right in the middle. Starts and idles fine but when giving it throttle it starts to stumble before coming onto the pipe and sometime back fires and once it runs on the main it runs good. Iv'e got  38mm A/S DGH needle and tried every position, 48 pilot 180 main. Fresh gas 50/50 mix race and premium. I am wondering if its electrical like maybe the coil. I swapped out stators and cdi (all OEM) and new spark plug wire. I didn't have a spare coil so thats my last hope maybe unless you think its jetting. Any help would be great.

Is the backfiring noise coming from the muffler or the intake?

[dirtyd]

That im not sure. I assumed from the muffler. Are you thinking reeds? But once it gets past the stumble and is reving out it rips.

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