Hey,
new here, and a new motorcycist. Riding (and breaking in) my brand new 07DRZ400SM and i notice that while cruising at lower RPMs at light throttle the bike tends to surge as if on the verge of misfire. Athough im not an experienced biker I am technically proficient with engines. The bike does this cold and hot, in warm air (80+ degree weather). It feels lean, so I imagine it would get worse in cooler air. The gas I use is 10% ethanol Im not sure if I could even find straight gas anymore.

Im not at altitude (unless you think about 600 feet is altitude?)
The bike is BONE stock, just bought it a couple of weeks ago.

I could take it back to the dealer and have him look at it but I thought it would be more fun to learn myself.

I did a bunch of searching but haven't found threads with this problem on a bone stock bike. I wonder if there is a simple adjustment to idle/pilot mixture that I can do that will straighten this out? Should I follow the procedure for testing the pilot circuit (screw out until idle smooths?)

indyphil said:

Well documented in hundreds of threads.. Yes the OEM set up DRZ is jetted lean. Often rearing it's ugly head by way of a bog or surging at constant speed.

the cure is not a simple turn of a screw.

But it is simple.

The 3x3 air box mod and a jetting kit from Dy or JD will fix what you have. And no, a dealer service call is not going to help, unless they are going to do the above. Check the FAQ subform above,, Look for the master 3x3 thread

If your in a higher gear and low rpm what you are experiencing maybe normal. How fast and what gear are you in when it happens? How tight/loose is the chain, if it was set correctly when it was PDI'd it may have stretched/settled in now you have ridden it making it to slack.
It is deffinately worth doing the mixture screw setup anyway, there will only be small rpm changes between 1 and 3 turns so don't be to quick to change it. Remember not to unscrew it to far as it can fall out whilst riding.

i have a stock 07 s and it does the exact same thing. nothing to worry about. like others have said if you jet and 3x3 it will go away. i haven't been able to do the mods yet so i just let it go as is. doesn't really affect anything.