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A little Help with a 2003 DRZ250 in Ca.

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My buddies bike is having trouble with the Carb. Everytime he twist the throttle it boggs out.

I've read the various post on carb isues and jetting, lean vs. rich. The only thing is it seems that most pertain to NON-Ca bikes which if I understand this correctly have a different carb.

Can somebody offer a little help to some troubleshooting a DRZ250 Ca bike that is bogging out? I removed the airflow boot from the rear of the carb. I noticed that the carb was spitting out a lot of extra fuel. I'm thinking the bike might be running rich.

Is there an air to fuel mixture screw on the carb? If not, how do you regulate air fuel mixture on a Ca bike carb?

thanks

p.s. The bike is completely stock. Was running fine before and just started doing this a few months back.

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I just finished my wife's DRZ250--changed the carb to the 49 state model, but it would still quit.

Major Problem---take the gas cap off. You'll see a metal contraption on the bottom held on with little plastic tabs. Inside there is a check valve about as big as a pea. Drill out the tabs and then it can breathe freely. Mine would vapor lock and quit--as soon as I did this problem solved.

If you have the stock CA carb you will have to richin it up. You must also drill at the tab so you can adjust the fuel screw. They run great when they are right---but it is a frustrating process to get there.

orator 520 😢

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If you have the stock CA carb you will have to richin it up. You must also drill at the tab so you can adjust the fuel screw. They run great when they are right---but it is a frustrating process to get there.

Hey Orator520,

Thanks for the help. Yeah the bike still has the original Ca. carb on it. What "tab" do I need to drill out to reach the fuel screw? Can you or anyone else point me in the general position of where I need to drill out?

thanks.

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There is a brass cap on the bottom of the carb. My recollection is that there are two tabs---You want to drill the one closest to the manifold.

***You will know it is the right one when you look at the carb--you should see a circular tube/ going straight to it. It is about 1/4 to 1/2 thick. Once you drill it out you will see the screw---this will be the fuel screw. You gotta love CA man.

Once you do this you can adjust it like a normal carb. I believe my father's DRZ250 is adjusted to about 3.5 turns out (that means screw it all the way to the stop--then mark it and count the turns back) I'm guessing yours is preset at 1 or so---this will make a huge difference. Now my father's DRZ has a Yosh pipe--so I would start out at 2.75 and move up--just my two cents.

Good luck.

Orator520

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Roger that.

Thanks for your help Orator520. I am going to give it a shot this weekend. 😢

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Hey Merrill,

Looks like I will be drilling out that brass plug. The bike starts and runs good at higher RPM, but falls on its face at slower RPM or light throttle. 🙂

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i also have a cali bike and and want to drill the plug out ,do you need to remove the carb to do this 🙂 and after that what would be a good start (screw tuns)with a stock bike

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Yes you will need to remove the carb before you drill. I set the screw 3 full turns out. Just finished drilling this plug out. If you have a real small wire with a bent end you can actually pull the plug out without drilling, it would have to be a real ridged wire though. Might be faster just to drill it out, it only tool a few seconds. Just make sure you don't drill into the screw after you get through the plug, you will be able to notice a difference after you get through the plug. I think I need a bigger pilot jet now, still haveing low RPM problems, like it's starving for fuel.

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Greetings Orator520:

I'm curious about the gas-cap check valve tip you provided. This is the first I've heard of it. Can you explain what exactly it is that I'm supposed to drill out? There are two little "nipples" that seem to hold the metal cover thingy in place, but I don't see how drilling those out would have any effect.

By way of background, I too am having the bogging issue that many people report with the DR-Z 250. It also has a "hanging idle" condition, where often it doesn't want to "rev down" after chopping the throttle. Mine has exhibited these problems across a very wide range of jetting and exhaust/intake combinations -- I've changed everything but the sizes of the needle and needle jet. I checked the valves too, thinking maybe the intake was tight or something. No go. My next step was to try to figure out the voodoo of measuring and setting float level.

Thanks,

MTB

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By way of background, I too am having the bogging issue that many people report with the DR-Z 250. It also has a "hanging idle" condition, where often it doesn't want to "rev down" after chopping the throttle.

Be careful not to mix issues related to CA version carbs with 49-state carbs.

Hanging idle is a pilot system issue. You need to turn the pilot screw out. If you get more than 3 turns out without fixing the problem, then go up one size in the pilot jet.

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My first suggestion is to buy an official shop manual if you do not already have one...best investment you will make. Details the carb and its break down. My 2001 had a similar problem and it ended up being a ill adjusted float, which was a little sticky.

After I opened up the air box (snorkel, cut 2/3 of the top out), re-piped with FMF PowerCore IV slip-on with Q insert, adjusted the clip setting per pipe install instructions and re-calibrated the float clearance the bike runs great. I live at around 2700 ft. and ride from there to 5k to 6K feet. Moose makes a great re-jet kit for the stock carb (Dennis Kirk) and it will also add to your performance a bit. Not sure about the CA. model, but the shop manual will indicate any special adjustments. 🙂

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>be careful not to mix jetting issues with CA state carbs

Thanks for noting that, but I was asking about the fuel cap, not the air-mixture screw (which evidently is concealed on the CA bikes). Anyway I think I eliminated that potential answer by running the bike with the gas cap off, and still finding the same hanging idle issue.

As for whether the "hanging idle" is a pilot-circuit issue, ... That's what I initially assumed, but I've already tried jetting the problem away to no avail.

A quick side note: I just bought a Motion Pro air-fuel mixture screw adjusting tool (a cable-driven screwdriver with a 110-degree angle on the end; $29.95 from my dealer, via Parts Unlimited). This tool makes it possible to adjust the air-fuel mixture screw without removing the carburetor -- a MUST HAVE tool for every DR-Z owner, IMHO.

Even using this tool, however, I failed to get rid of the hanging idle with the current pilot jet, which is a size 40.0 (one size bigger than stock). (Air temp in my shop about 55 F, altitude 337 m.) Last fall I tried to fix the problem with a 42.5 pilot, but still couldn't fix it, even turning the air screw 3 turns out. But I want to try again now that I have this tool and can adjust the air screw while the bike is running.

Nevertheless, I suspect a sticky/maladjusted float will turn out to be my problem, as it was for dipper_skipper. (FWIW, I checked for air leaks at the intake manifold by spraying starter fluid on it while the bike is running. No go.)

Regards,

MTB

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Nevertheless, I suspect a sticky/maladjusted float will turn out to be my problem, as it was for dipper_skipper.

Since you will probably be taking the carb off to look at the float. You should blow out the various passageways with compressed air. Strange symptoms which do not respond to normal adjustments are sometimes caused by small blockages in the jets or passages.

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... blow out the various passageways with compressed air. Strange symptoms which do not respond to normal adjustments are sometimes caused by small blockages in the jets or passages.

That is an excellent suggestion. Of course I have inspected everything thoroughly, but haven't actually blown air through it. Thanks!

Regards,

MTB

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