wingstar
XS400 Enthusiast
Fairly certain I read somewhere in this forum that if you get new air filter or exhaust then you have to put different jets in your carb. How exactly do I know what jets to put in?
You usually prove out the need through trial and error. Beginning with whether you have the correct ones to begin with, so many people with no logic tend to mess with such things thinking they are 'doing something'. They are all right, messing things up. I for one am firmly convinced that screwing carbs up on bikes is a male puberty rite of passage thing of some sort.
CV carbs like these bikes have tend to let you mod somewhat with no changes at all, they self jet so to speak. The CV quality lets them self adjust jetting for a couple of steps anyway.
Not nearly all mods lead to the absolute need to mod the jetting upwards in the usual thought of way and some mods even lead you toward lowering jet number, telling you your mod likely cost you power. Many cannot accept that, it being drilled into us the jets have to change up.
One other CV trait that can throw one for a loop..........the same ability to self adjust can make an unuseable jetting setup seem to run for a while until the motor carbon coats in fully to the new setup, then and only then will it begin to spit its' guts out. Meaning the new jetting you did that 'runs perfect' that day will likely not be what you suspect is wrong when a month later the engine begins to run into blind staggers at getting on it. Will somebody be able to put 2 and 2 together on that later?
A tip.........most never make the connection, and bike is then doomed to run like crap until next buyer gets it.
Can I get away with not changing the jets if I replace the exhaust system then?You should know that the OEM mufflers are big because bigger allows more space to kill sound in. Commonly replacement ones are smaller and end up being louder as a result, if not then they are often less efficient than OEM and that alone often kills any jetting increase as unneeded.
You usually prove out the need through trial and error. Beginning with whether you have the correct ones to begin with, so many people with no logic tend to mess with such things thinking they are 'doing something'. They are all right, messing things up. I for one am firmly convinced that screwing carbs up on bikes is a male puberty rite of passage thing of some sort.