Hello I have a 03 400ex with lots of goodies getting installed soon. My question is do the Dyno jets really give that much power increase or is it all talk and are the readily avalible if I need to switch jets do to enviorment. You can see all the stuuf I got in my signature if that helps. Thanks.

 

If your bike is still running factory standard jets with all that kit on it you definetly need to re jet to a bigger jet (higher number) . The pipe and filter you have let more air travel through your engine to get the benifit of this you need more fuel.

Your bike will be running lean at the moment which is bad news in a four stroke and genraly fatal for a two stroke. changing the jet is a cheap job which you could do yourself with a manual and a few tools.

there is no need to buy a dyno jet kit just a few jets will do.
Good luck maybe some one with a similar machine to you could give you a few suggestions on which size to start with.

 

Does the dyno jet kit increase the power.

 

Sandrider503-My wife has a 440 ex and although we do not use dyno jets i can give you the keihin jet numbers that we run on her 440.With your cam -pipe and k&n i would suggest a 160 keihin or the equivalent in a dyno jet size if you are going to be doing most of your riding on the dunes.You asked if the dyno jet kit increases power and the answer would be yes if you jet your carb properly for the mods-fuel and altitude that you ride in.You can probably get your ex to run very well by just changing the main jet and on your honda it is about as easy as it gets so dont hesitate to install the main jets yourself.You should not continue to run with the stock jetting (if you have been) with the mods you have listed because you are going to be lean and that is very hard on your motor and particularly hard if you ride in the sand.

 

Hey thanks alot what makes dyno jet so different from the rest why does that paticular jet kit make your power so much.

 

i wouldn't waste the money on the jet kit. just buy individual keihin jets.

 

This is where I disagree with everyone and will probably get flame for it. If you have never done a rejet yourself you are better off to buy the kit because it will have all the instructions for you to choose which jet size you need. And if you don't feel comfortable doing it take it to a shop they are only gonna charge you like $40 and it will be perfect.

 

So the dyno jet kits aren't what they are cracked up to be.

 

in my opinion, no. the increments aren't as small with the dynojets. for example, the kit doesn't come with a 150. with the keihin jets you can get 150, 152, 155, 158, 160, etc. there are larger jumps in the jet sizes with the dynojets. the needle is a different taper but i can't imagine it makes that much difference if any. if it comes down too it you could always order a different honda needle with a different taper or diameter. i am using the stock needle with the clip lowered one position in my 406 and it runs just fine.

 

I'am gonna just run the Keihn Jets. If I need jets most dealerships or parts stores will carry Keihn over Dyno. So I will go with the most accesible. Thanks