Please Help With Carb Tuning

Story: Just did a 3x3 mod, Dynojet jet kit, and installed Yoshimura RS2 system. Started up fine with half choke (as it always has when cold starting), behaved like normal while warming up, made it halfway around the block and it stalled when I coasted with clutch in, after a short burst of 3/4ish throttle. Hit the started switch while still rolling, got a little more power out of it, then stalled again when coasting.  Wouldnt start this time while rolling, so I stopped, pulled the choke, started up (figured at this point must be lean at idle), closed the choke, got rolling again, stall again, coast the rest of the way to the garage.


Facts: I installed the Dynojet needle, on second clip from top, with thick stock washer and nylon washer below the clip on the needle, and a thin stock washer on top of the needle. 155 main jet, 25 pilot jet, mixture screw 2.5 turns out, RS2 still has the spark arrestor installed. 


Once back in the garage, engine still warm, turned fuel mix screw out to 3 turns (figuring it was lean after only starting on half choke), but wont start. Will only start with full choke. Then proceed to try multiple different mix settings from 2.5 to 4, wont start, only full choke will start it, but will not idle. also tried adjusting idle higher, didnt help. 


What do you suggest I try next?

time to pull the carb again and find whats wrong .. actually first i would drain the float bowl a couple of times and make sure the lines are all hooked up, especially the one on the tank pc, and make sure the float didnt hang and flood the crankcase with fuel, that will cause a similar symptom to .. but yeah, a problem like that will be beyond needle clip positions and mixture screw setting .. it will be intake leaks or trash or something not right in the assembly of the carb, internal leaks ect ..

I cant believe I'm even going to tell you guys this, but....

When i removed the fuel take, i drained it completely as I could. When i reinstalled the tank I only put about 2L of fuel in, you know incase it wouldn't run and I had to remove the tank again.

So I guess half way around the block was enough to hit the reserve.

After priming the auto fuel valve the first time I didn't think to try that again until i came in for dinner, then it hit me. I believe the first times it stalled it was from a bad mix setting, but that was also about the time the reserve kicked in. Still doesn't explain to me why it would start with the choke.

Vacuum line connected..?

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Similar Content

    • By BikeChimp
      I'd like to turn my UK 2004 DRZ400S back to stock airbox (snorkel) and jets, needle shim position etc
      When I bought it the PO had fitted a Sigma6 kit and done the 3x3 mod but is doesn't have a tapered needle like the JD and other kits. Took me ages to get it running right, however it still runs rich and I'm fed up of arsing around with it. 
      So I've bought a standard airbox without 3x3 hole, stock exhaust.
      Q1 The Suzuki manual says this Mukuni BSR36 (29FA) carb should have a 142.5 Main Jet but the Clymer manual say its a 135.  In UK everything's from sea level to 1000m. I'm in Sheffield so nothing gets above 500m even in the Peaks (Hills). Any UK owners or anyone else know what the correct jet should be?
      Q2 Says the original needle is a '5DH36-2nd'. The needle has 5 notches on it. Currently set at 2 clip from bottom. The Suzuki reference says needle is 5DH36-2nd, Does the 2nd bit mean 2nd from top or bottom?
      Q3 - Does anyone have a detailed photo of the shim order just in case it was assembled wrong. (mine is attached)
      I know most people on here are going to be horrified I'm taking back to stock but any help on above would be really appreciated.

    • By Bgringo
      I've read a lot of threads about this but still haven't found exactly what I'm looking for.  I'm pulling my 2004 DRZ400S out of storage sometime this week and getting it ready for the season.  I live at 9,000 ft, but my first ride of the year is probably going to be at around 5,000 ft.  I was going to pull the 145 main jet I'm running and put in the 150 adjusting the needle from the 2 clip to the 3rd, then re-jet once I got home.  I already have the extended fuel mixture screw in place so I started thinking that I should just run the 150 jet set up and adjust the fuel screw to compensate for the higher elevation where I'll be doing most of my riding.  I will be going down in elevation for rides until late May or June depending on snowfall, but riding on the street when I'm able.  Are there any disadvantages with this?
      I'm new to posting on this forum, so please forgive me if I didn't get the right search words in and there is already a post about this.
    • By Markl5557
      I am currently running 10w 40 Belray non synthetic and I want to switch to full synthetic amsoil .... is it ok to switch from regular to synthetic? I have read it’s not safe to go from synthetic to regular can someone explain if it’s safe to go from regular to synthetic!? Thanks !
    • By RockyMtnMark
      Good Morning,
        Last night I measured my valve clearances for the very first time (I know...) on my DRZ400S.  It's a 2002 and I've owned is since 2011.  I bought it with t's got about 15,000 miles on it and most of it's miles these days are on dirt.
      Intake specs are 0.10-0.20 mm.  Exhaust specs are 0.20-0.30
      My intake valve clearances are in spec, forgot to write them down.  My exhaust valve clearances are between 0.1778 and 0.2032 which is slightly out of spec.  They are no more than 25 microns out of spec.  My question is, do I really need to shim these?  Will this kind of out-of-spec cause performance, mechanical, or other losses?  As far as I can tell, I'd have to buy a whole shim kit which is like $80.  Thanks!
    • By Zach440
      Selling my 2009 Drz400sm. Been a great bike but it’s time to let go . Not looking for any trades - spring is just around the corner ! Located in northern Virginia . Cash only $4200- willing to negotiate I have some wolfman luggage options available as well. Love to make a package deal for someone 

      -11640 miles . Mild off-road never wrecked.
      -Oil / filter changed every 1500 miles
      -New did chain , brake pads , front sprocket at 10400 miles .
      - valves checked and within spec at 10,000
      - jetted with JD kit and 3x3 mod
      -doubletake mirrors
      -waterproof usb wired and located next to Speedo
      - drc large foot pegs , barkbusters with integrated turn signals . 12oclocklabs tall delete with upgraded circuit board
      -thumpertalk case savers
      -sergeant seat (amazing) and Clarke 3.9 tank (190mile range )
      - fog lights wired in so they shut off with high beams
      -Shorai lithium battery
      -led headlight

      - stock gas tank and seat will be included

      The bike is dirty in photos and I apologize my water is currently disabled outside due to freezing temps . Radiator guards and skid plate NOT included but can be for some extra $$. Rear tire could be replaced but front is fine .