Where to start

Well ok I have had my bike for a few weeks its a 05 drz400s with 2400 miles. Untill today the bike has been out of comission for the past week. My petcock had failed and the bike flooded about 2 gallons of fuel in the crankcase and all the way out the airbox. I ordered a WR400 style petcock with reserve and plugged the vacuum line(bike has IMS oversized tank).

I changed the oil, installed the new petcock and started the bike ready to ride.

The bike cranked immediately and ran well but it still was slow returning to idle from being revved. What is causing this? No airbox modification has been made and the exhaust has a stock header using a white brother e2 tailpipe

The bike did not do this the first week I had it and the throttle is not restricted in any way. I have never had a bike this nice but right out of the bat it has drawn some red flags.

I bought a DRZ400 dirt model header to replace the "S" model stock header and plan to modify the airbox but would like to work out this problem before I go changing anything else.

Let me know what you guys think, thanks

Also this bike is a California model and the evaporator has been removed if that matters

thanks in advance



Need to know if any carb changes have been done. The first thing to do is to clean and adjust the carb. Is the float needle and seat in good condition? How about the "O" ring on the float valve. Adjust the float level. Clean the jets. Inspect the diaphragm. Verify the small O" ring under the top is there. Needle retainer in place. Uncover the idle mixture screw (under a seal cap) if not already done. Adjust to 2.5 turns out. Record all the jet and needle sizes.

Verify the nipple under the carb (for the CA emissions) is capped off. Verify the gas tank is vented someplace. (CA cap is sealed). Don't give up yet, the fun has only started.

So do i need to take the carb completely off? This is where I lack the experience but if instructed how Ican do. Does the seat/tank need to come off in order to do so?

I do not believe the carb has ever been tapped into.

also nipple is def capped and the tank is vented.

I will get to work on the air screw and also try to get an audio soundbyte for youand check back later


Yeah...unfortunately you'll have to remove the carb...think of it as good practice. my E (FCR) had a hanging idle .... broke into the carb to do a cleaning .... hasn't happened since. I think the pilot might have been the culprit?

OK I thought I had verified that the "nipple under the carb (for the CA emissions)" was capped off but now I am not sure.

There is a long u-shaped tube coming out of the carb on the engine side, on the bottom right near the boot that has a Mini cylinder shaped filter on the end of it?

Is this part of the California model? This piece is something Ive never seen before on an engine. Let me know if that is what needs to be capped off

thanks again

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