Good morning everyone...

First off, my apologies for the typo in the title to the thread...

So I took my DRZ out trail riding this weekend and had a pretty uneventful but fun time. I got the bike off the ground a few times, you know, nothing more than a few inches, but off the ground it was.

No crashes either, thank goodness.

I also commute to work on this bike every day and I noticed yesterday that not only does the motor seem to bog slightly at higher RPM's, but upon aggressive throttle application when stopped, the motor will completely cut out. It starts right back up again with no problems. This is after the bike is well warmed up.

And at other times, I can hit the throttle as agressively as I want and she revs just fine, no drama whatsoever.

The mods done to this bike thus far are: JD Jet kit, 3X3, 4.25 gallon Acerbis E model gas tank.

I suspect that I am running into the limitations of the CV style carb on this bike, but is there anything else that I should check? I've looked at the intake side of the motor and cannot find any obvious vacuum leaks.

Take care all,

JT

Eddie Sisneros said:

Not yet. I did have problems with the bike cutting out when riding over anything that would cause the side stand to drop, as can be expected.

The current problem occurs when I blip the throttle at a stop.

Eddie Sisneros said:

I used the suggested settings for a DRZ with a stock exhaust. I installed the JD jet kit more than a year ago and never had this problem until two days ago.

Eddie Sisneros said:

It's been in the 70's here in Seattle, certainly warmer than a month ago. I had the bike quit on me both yesterday afternoon in 70 degree weather and at 5:45 this morning and about 50 degrees.

The idle speed seems normal although come to think of it, at times it sounds ever so slightly lazy.

Eddie Sisneros said:

Stock fuel screw.

Eddie Sisneros said:

I wonder why this problem came about in the first place? Normal wear and tear?

BTW, thank you for helping me trouble shoot this!

I'll try increasing the idle speed half way through my ride home from work today and report back!

Thanks,

JT

My son-in-laws totally stock 07SM does the same thing. Although it doesn't matter how long the bikes been running. Any and only a quick blip on the throttle while idling almost always results in the engine just stopping. It always just starts right back up though. I don't remember the bike doing that back when he first got it and he hasn't tweaked on anything that is engine or carb related. Only thing I can figure is the air filter which he doesn't clean very often may be the culprit.

DOHCFOX said:

More than likely that is what you are running into, the limitations of the CV carb. Mine does the same thing if it am sitting still and twist it wide open. The bikes with the FCR type carb with an accelarator pump usually won't die when twisted wide open. Just throwing in my 0.02.

I've been having a similar problem with my 08 Z. At stop lights i'll aggressively give it throttle, I love the sound of my uncorked Yosh pipe, and BOOM!! I hear a loud pop and also feel pressure under my seat as if airs coming out my 3x3 hole. Bike dies.

Heads turn my way....

She start back up fine.

If the idle screw doesn't help, then it may be that the pilot circuit is too rich. If you had an extended fuel screw you could just reach in and turn the screw in to see if the problem goes away.

I had the same problem with my DRZ (stalling when cracking the throttle off idle, even sometimes in neutral). I decided to start by tuning the pilot circuit (I have the Dynojet jetting, a 25 pilot jet, 3x3, full exhaust), which required me to remove the carb again and install the extended fuel screw. It was well worth the effort because I found that my screw was out way too far (I had set it at 2.25 turns out after jetting, based on the recommendations I read here). I ended up turning the screw out just 3/4 of a turn, and it seems to have fixed my problem. However, I haven't had a chance to ride the bike much since the adjustment (waiting on a new chain, bla, bla, bla).

Thanks for all of the replies everyone! I've been riding the bike daily and have still had the same problem arrise occasionally. Interestingly, many times, the bike rides great with no hint of dying suddenly upon hitting the throttle.

So I'm going to go out on a limb here and suggest that due to the limitations of the CV carb, my float bowl must be emptying at certain times according to how I am riding and it's at those moments when the bike is most prone to dying when gunning it.

Otherwise, she runs great.

Cheers guys!

JT