2 valks run completely different

[clsimmonsjr]

here is the question, not really a problem, I have a 99 IS and a 98 tourer, the 99 runs smooth as silk with stock pipes and the other 99 I had with 6 into 6 did also, the 98 has six into six and backfires and pops a lot, runs good, just a lot of cracking and popping.  I thought the carbs needed adjusted, but that didnt change anything,  do you think anything is wrong, or is that just its nature?

[Steve K (IA)]

Sounds like it is sucking air where it's not supposed to.  First place I would look....is the header nuts tight?

[mikehallbackhoe]

the cobra pipes will make the valk pop , not enough back pressure, and running too lean

[gregc]

 I have to question that Cobras make the Valkyrie pop.  My Cobras have been on since it had 700 miles , and I have never heard it pop.  Sounds to me like it is getting extra air into the mix from somewhere, start checking for a vac leak.

[fldragon6]

Make sure that the upper and lower clamps above the carbs are tight. They have a tendancy to loosen up over time.