dont really have nothing in mind except that both units i have are tuned correctly with mods they have on them. The wifes unit (800r) was backfiring (have HMF Performance slipon) evey now & then when going down hill but since then i added a dobeck tuner at which it solved the backfiring but sucking gas. Using 50% more gas( was around 25 mpg) than it did without a tuner. I've been talking with Dobeck & doing some trouble shooting with them on hers. On my unit (916cc), none of the issues you mentioned. Can't say much about the gas it uses (916), i get around 11MPG.what kind of stuff do you have in mind? if the "tuning" is off it will run crappy., does your's run crappy? popping? banging? hesitation when you push the flipper? sucking fuel like a gas-o -holic?