Jetting DRZ400E w/ Mods for 5-7.5K Altitude

[dustydrz]

I recently moved my 2006 DRZ400E from Richmond, Virginia to Denver, Colorado.  I have no idea what the current jetting is but I know that it was jetted richer from stock in Virginia and is to the point it is fouling plugs in Denver.  It has the original Keihin FCR 39 carb, common air box mod, K&N air filter, power bomb header and an FMF pipe (in other words, it breaths heavy).  Any ideas where I should start with re-jetting?  Any way to change the jets in this thing without taking the carb off?  It's my first time working with anything other than the needle in this carb and I would appreciate any tips and tricks.

[dspy21]

nice! I had the fcr mx 39 when I had my DRZ running strong in Denver so not exactly sure if the jetting is slightly different or not for the slant style (is that what your factory E model has?) Anyways I had jetsrus hook me up for cheap with a EMP and EMQ needle (EMQ was strongest performer in 75+ degree weather) and then 150 main jet, 42.5 pilot (extended fuel screw out 1 turn)

I was able to remove the breather box with the carb still attached (kinda a pain) after removing the MCCT. then loosen clamps on carb and twist enough to access jets and needle. I did this multiple times so it got easier but you will curse a few times no matter how you approach it unless you have replaced the carb before

Edited June 3, 2017 by dspy21

[dspy21]

you do this after the gas tank is off of course.. and noticed you have the auto chain tension but same concept

[dustydrz]

Thanks!  I might just take it off to clean it out and get a visual on everything while I'm at it.  I am not sure if it is the slanted or MX but from what I can tell it is the slanted.  Any ideas from the pics?

[dustydrz]

And what did you have for exhaust and intake at the time?

[dspy21]

that's definitely the slant style carb. jetting should be similar though to the mx version, it just doesn't have a leak jet.. I had an MRD exhaust with 3x3 mod. With you're full system FMF should be similar air flow. I always recommend getting a few extra main jets around where you think what yours will be so you can experiment but what I listed above should be damn close.

[dustydrz]

Thanks!  I got everything removed and the main jet is currently a 140 and the pilot is a 45.  Before I knew this, Jetsrus recommended starting one down on the pilot and testing between 140 and 145 on the main.  I was surprised it had a 140 in there based on this and everything I've read (and it was actually running a little rich in Virginia).  With that Mike at Jetsrus still recommended trying the next couple down from 140.  I ordered the 40 and 42 pilot and the 132, 135, and 138 mains (waiting on them now).  I also ordered the extended fuel screw to replace while I had the carb off (I would highly recommend everyone else does the same).  I'm going to start with the larger jets; here's to hoping I nail it on the first go because I never want to take this carb off again.

[30x26]

do you have the stock needle? code and position of the needle make noticeable difference over main jet too. 

assuming stock needle a starting point is:  main 150-155, dxp needle 3rd or 4th clip from the top . you can run 45 pilot jet , stock was lean at idle. start with screw around 1.5-2 turns from closed.

 

Edited June 9, 2017 by 30x26