Jetting my 400 ex advice please

[jason43050]

i got a 2005 400 ex. just a exhaust tip 2" opening. took the factory tip and baffle off. stock air filter and box. the factory jet was a 148 jet. the dynojet kit instructions told me to put a 142 jet with a stock exhaust and a 146 jet with an aftermarket exaust. i put a 155 jet in and put the dynojet needle in with the clip and washer on 3rd notch down. with fuel screw fully seated i went out 3.5 turns as it said to in the instructions. my exhaust isnt completly stock cause of the exhaust tip allows more air to get in. when i start it up it pops a bit when idling. i had it wound out in 2nd gear and it backfired once pretty good. i tried 2nd gear again and it didnt backfire again. didnt get to ride long. havent looked at my spark plug yet. does it sound normal? or what should it be sounding like? it felt like it had more power. the exhaust pipe didnt take long to get hot. i knew to this, some advise would be appreciated.:confused:

[quad71]

dyno jet neddle must use dyno jet main jets also do you have the air box lid on or off.

[jason43050]

no the air lid was on. yes i used the dynojets main jets. when i decelerate(engine brakeing) the exhaust pops a little. someone told me it sounds like its too lean.

[quad71]

i dont think your to lean the poping is from the tip that you put on. just put the jet in that dyno jet said to. also if your going to run the lid on. check out the 2006 450r air box intake tube i have set mine up like this works good. i have LECTRON carb one jet to adjust you just turn the neddle to adjust. also the pop could be to much fuel >rich the numbers on the dyno jets are not the same as stock jets . example a 152 stock jet may be leaner than a 152 dyno jet neddle.

[blue150]

Does anyone know what kind of jet I have?

It says 175RD

[Buffalo400]

Why use Dynojets main jet with a dynojet needle?

I have a dynojet needle and I use keihein main jet and my 400 run well...

[LightningEX]

I just rejetted mine.I can say with a full DG system,k&N filter and UNI filtered air vents in the top of the box the 170 jet(which is the highest I got with the kit)works great with the needle on the third notch.Make sure you are counting the notch from the top down and the washer goes on top of the c clip.What altitude are you at?

[curious george]

you might have a problem with elavation to see how high up you are or how low gusseing does not always work that well. that would just be a change of jet and fuel mixter screw.

[blue150]

Hey guys does anyone know what make of jets have RD stamped on them

[jason43050]

Originally posted by curious george
you might have a problem with elavation to see how high up you are or how low gusseing does not always work that well. that would just be a change of jet and fuel mixter screw. how do i find out what evevation i am at?

[Ridered416ex]

take the air box lid off and it most likely wont pop anymore

[blue150]

Hey guys does anyone know what make of jets have RD stamped on them

I am doing a 426 would a 175 jet be a good place to start