Motorcycle Repair: jetting, cherry bomb, exaust system

Question
I thank you for your quick response.  i asked the question about  putting a original exaust system on my ninja. If i did put another 4-1 exhaust on the bike and did not seem to have any problems could i really be hurting the bike in a way that i dont know about. if it is running to rich how will that hurt the bike. i have another chance of buying a 4-1 exhuast that the person claims that could be used on jetted carbs. could this be true. if i could get intouch with the last owner is there any jet number that he might be able to give me that could help picking another exhaust system. or should i just stick with the one i have now. someone cut off the 4-1 and welded a cherry bomb on to it. it dos not look that bad but is very loud  thanks again   tony

Answer
They arn't that sensitive to be honest, the chances are that jetting for one 4/1 is pretty similar to yours, the jets all have their numbers stamped on the side.Running a bike on the rich side won't harm it too much mechanically, youjust might find the plugs fouling due to far too much fuel being let in