Ok , so i am new to this sport. I bought my bike in Feb and when i picked it up they said it was jetted for the colder weather. Now that it is warm, i am noticing some problems at the high end of the throttle. it seems like it spudders. Does this mean i need to re-jet? What is a jet? How do i know what jets are in it? How do i know what jet to buy?


Oh , my bike is a 2004 Z400. No mods yet.Well except for the Skid Plate and the Shock Covers.

 

top end sputtering usually means rich jetting. try going down one on the main jet, or if the stock main is still in, maybe they raised the needle clip. check to make sure both jet and needle are stock, and you should be back to running normal, depending on your elevation ( jetting is also altitude sensitive, too )

 

All I can say is, just find a friend or somebody that knows how to jet a carb, and have them show you.

 

In basic terms...........The larger the jet the more fuel your engine will recieve. If it was jetted for winter they put a large jet into it because the air is more dense in the winter{more air, more fuel}. {same way with altitude....you have less air so you need less fuel} Unscrew the fuel bowl on your carb and you can see what jet is in it.
Look here at #33
The are #'s stamped on the jet, maybe ask the dealer what they suggest compared to what you have now. The jets are cheap and real easy to change out.

Hope that helps I'm a better talker than a typer![img]i/expressions/face-icon-small-happy.gif[/img][img]i/expressions/face-icon-small-happy.gif[/img]

 

ThrashAndCrashUntilItsTrash,
Thanks for the Basic terms! I will contact the dealer to find the Jet the Suggest.
One thing i should mention. I went to clean my air filter yesterday and the Air box
cover was not on correctly. I wonder if this is the cause of my sputtering?