Hey guys im new to the DRZ world and bought a bike with a boat load of mods and money dumped into it. the problem i am having is with the carb..runs out fine, but when you hold it steady throttle 1/4 to maybe 1/2 it will sputter and buck a little..give it more gas and the sputter goes away but hold it steady again and the sputter will start..mods and carb set up listed below.. Also after adjusting the needle clip to 5th spot down seems i have to give it gas while i am cranking it over for it to start

2004 DRZ400S converted to SM
434 BB
Stage 1 hot cams
FMF power bomb header
Yosi slip on
E model subframe and airbox (3x3)
MCCA

FCR39 carb off DRZ400E
Needle on 5th clip down
45 pilot
165 main
pilot screw ? all over the place iv been trying to play with it to get it to run better

Carb is the E model slant body FCR, right?
Need the code letters on the needle or color mark if no code letters or any ID.  Clip is on 5 (counting 1 at the top of the needle), right?
Coast enrichener (CE) intact or gone?  If gone, what pilot air jet?  Nipples plugged or connected with a hose?
165 min jet is pretty big for any set up.

Noble, on 08 May 2012 - 06:40 PM, said:

yes sir,
its a slant body E carb.
dont know the code on needle. it was a brass needle with 6 slots in it. and yes 5th notch from the top.
CE has been removed..Nipples are plugged.
I was thinking the 165 was a little big, but it pulls hard at full throttle the problem im having is at part throttle.

The needle code is critical to the operation and tuning of the carb.  Need to know that.  Original needle is aluminum so if yours is brass or copper color, it has been changed.  There should be 7 clip positions.
CE has been removed..Nipples are plugged.----OK.  Now it is important to look and verify the pilot air jet.  it is located on the left as you look into the carb with the air horn removed. Original is 65.  CE removed and the side nipples plugged, it needs to be 100 to work with a 45 pilot fuel jet.  If it is still 65, there is a way to work with that - run a hose to connect the 2 side nipples.

I was thinking the 165 was a little big, but it pulls hard at full throttle the problem I'm having is at part throttle. -----I understand.  Suzuki used 165 in countries that got the open air box.  Still a bit smaller may work even better. 158, 160.

Edited by Noble, 08 May 2012 - 09:46 PM.

Noble, on 08 May 2012 - 09:46 PM, said:

Noble ... I dont have any problems with my carb yet but when I do I will be sure to call on you when that time comes . i read this and holy crap do I feel dirt bike stupid now . you know your stuff Hoss .

havent checked the airjet size. pulled the brass/copper needle out this morning and like you said it has 7 clip pos. i had it on 5, but moved it to pos 4. . it seemed to clear the sputter up a little and it starts a little easier,Still have to hold the gas a little some times.. adjusted my pilot screw and i get the highest idle at about 1 turn out..if i let it idle and twist the throttle wide open as fast as i can it stalls right away, but normal riding seems better..

the biggest problem i am having now is the idle will stay around 4k after i come to a stop and slowly fall maybe a min later..

scites, on 10 May 2012 - 07:14 PM, said:

Try turning the fuel screw out to 2 turns...

Edited by CraigoDRZ485sm, 12 May 2012 - 01:10 AM.

2 turns out the idle is so low i have to turn my idle screw all the way in to get it to idle at like 1800..got it running pretty good at 1 1/4 turns out. i may try a 42 pilot jet and even a different needle down the road..