What would make a motorcycle run rough?

Friend has a victory 100 ci v-twin motorcycle which has gradually started running rougher. Was just when he revved it, but now always (idles rough, misses, and when he revs it). First he thought was due to fact that he removed one, then both baffles from pipes, but now wonders otherwise. Any suggestions where to start besides bringing it to a mechanic and getting overcharged?|||If your friend did not address the airflow changes of removing the baffles by either re-jetting the carb or adding a fuel injection processor depending on the bike, then he may be experiencing detonation.Until the last couple of years, fuel injection systems on bikes did not compensate for airflow changes. Now they work much like on a car, though still might not compensate enough for that big a change. You did not mention unusual noises, but milder detonation often cannot be heard, though it will still cause damage. Check the spark plugs - the electrodes may be eroding from the heat and would explain the symptoms you describe





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Generally removal of the baffles on a v-twin - when done properly by someone who knows what they are doing, will usually reduce low end power and torque, while increasing it on the high end. I used to run my '05 harley dyna sans mufflers (same effect as removing the baffles) but you gotta keep the engine screaming (well, more like a high pitch growl) in order to benefit from this mod. But if you're willing to ride like you think its a high revving jap four, you can beat people who spent a few grand at their dealer on upgrades for about $300 (for a high flow air cleaner and fuel processor). It also happens to be really, really loud and will wake the dead from a mile away. also those TC88s run smoothest above 4K RPM. I suspect a victory would benefit even more because it was designed without the self-imposed technological limitations that Harley engineers face.|||By removing the baffles he may have caused enough change in the way that the engine "breaths" that it is now running lean. IMHO when you go to a mechanic you are paying more for what he / she knows than what he / she does. Re-tuning that bike for an inexperienced hand could be time consuming at least, frustrating most likely and lead to greater expense at worst. Good luck to ya.|||Start by replacing the baffles and see what happens. Does your buddy think he is Harley rider that he has to make a bunch of useless noise? I am reminded of Macbeth, Act V, Scene 5: "A tale told by an idiot, full of sound and fury, signifying nothing."|||Yep, that would do it.





Could also need a fresh air filter, plugs, oil.|||my dirt bike did the same thing try adjusting the float bowl