I've been looking at a Leo Vince GP Corsa Carbon slip on exhaust and also looking at a dyno jet kit.
One of the Leo Vince suppliers told me that the GP Corsa exhaust was designed for use without any "re-jetting" (I asked about a dyno jet kit).
What does this exactly mean ?
To be blunt ... it means the fancy aftermarket exhaust system doesn't do anything. (This is actually rather typical nowadays ... stock exhaust systems are usually pretty well designed, even for a Ninja 250)
If it did something (i.e. somehow increased the amount of air going through the engine), you would have to re-jet it.
How do you know if an exhaust is compatible with a jet kit or not ?
You DON'T. Only way to know is to go by what previous people have done who have installed the same one. For that, go to internet forums dedicated to that bike (there are plenty) and try to find someone who knows what they are talking about as opposed to only knowing about flush-mount signals and fender chops and blingy lighting (that is the challenge, but they are out there).
Also, if I had a jet kit installed (if), and added an exhaust designed to be used without a jet kit, would this damage the bike in any way ?
Given that we have already more or less established that the exhaust system doesn't do anything ... it won't matter whether there is a jet kit installed or not.
Having said that, Ninja 250's are notoriously lean right from the outset. But there's no need for a full jet kit to fix this - just shim the stock needles, install next-size-bigger pilot jets (which most jetting kits don't include!), and MAYBE change the main jets IF the exhaust system warrants it. All these parts are available separately, e.g. through Winner's Circle on Steelcase in Markham ...
Then why did the dealer "make it sound" like the Leo Vince exhaust shouldn't be coupled with a jet kit ?
Who knows ... ! ! !
The guy behind the counter isn't necessarily a race engine tuner. Most likely, he can only go by what the manufacturer says in their promotional materials.
