ATV Florida Forum

Well, I have installed my exhaust today (stock air filter) and my question is this.....After I installed it, I figured I would crank it up and it would run "rough" well, it didn't...so I decided to run it up and down the street a few times figuring now it would "lag/hesitate" or do something out of the ordinary...well, it didn't. My bike seems to run as good as it did before I put the pipe on it. Has anyone ever installed a slip-on exhaust and NOT have to rejet the carb?
I know from experience with sportbikes the only time you would need to tune/rejet the carb is when you would add a "full exhaust" and Air filter...but not with a slip on only...Am I just lucky or is there a possibility that I still need to rejet? I have a jet kit and an appointment at a mechanics house on Tueday night to rejet it will he be able to see something that I don't?

first of all what kinda bike is it.

the jetting has more to do with the intake side, if you left the lid on the airbox its no different then taking the endcap off as far as jetting goes, the amount of extra fuel your using is very minimal with the stock intake on there. in your case id just take the stock main jet and find a drill bit the same size as it and just hone it out, a strait drill bit will take the taper out of the bore to slightly oversize it, or you could go a few points bigger if you want to buy a jet, either way your change in jetting is minimal but it still needs to be done or it will probably run hotter once you start romping on it all day out in the florida heat since it is running on the lean side.  just becasue it runs good doesn't mean its not running lean, you have to be pretty considerable lean before it starts becoming noticeable on a pretty dull 4 stroke realistically. you probably just rode it around the street a little bit right? wait till you take it out for a day of riding and get the motor super heated, youl probably notice its starting to pop on the downrev once it gets hot and needs more fuel.

you could also adjust the air/fuel screw, if its a fuel screw turn it about 1/4-half turn out, if its an air screw go an extra 1/4-half turn in. fuel screws are pointy and air screws are blunt if you dont know what youv got.

ok...that helps out...I already have the jet kit that was purchased with the expectations of having to do it with the new pipe installed. I was just expecting to run "rough" at some point, so I'll go ahead with my plans to have it rejetted on Tuesday as planned.