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2003 DRZ 250 Issues

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Hey all. Been a lurker for a while but decided to join after i purchased my 03 DRZ 250 and ran into a few problems.

Firstly, there seems to be a really weird idling problem, it's hard to explain, but i'll do my best. :p

When i first start the bike, it idles fine, but once it's warmed up the carb seems to have a mind of its own. The bike will idle, then all of a sudden it'll "cough" like it's going to stall (but doesnt) then the idle starts to rise by itself. The only way to bring the idle back down is to give it a quick squirt on the throttle... sometimes it takes more than one squirt and the idle will settle down, that is untill it coughs again, and the above process needs to be repeated.

I pretty much put it down to something sticking, like the float or slidder or something. But the bike also has some issues whilst im riding it. When im slowing down the bike seems to cough and splutter a little as im going down gears, but not to the point where it will stall. So i've kinda changed my mind and have put the issue down to the carb not being tuned right.

I spoke to the dealer i got it from, they told me to wait for the idle to rise again, then wind out the thumbscrew on the side of the carb (i assume its the mixture screw) a bit and see if calms the idle down, but seeing im not overly mechanically minded i couldnt even find this imaginary thumbscrew. :ride:

So to make an extremely long question short, should i start poking around the carb trying to work out which is the screw im looking for, or does it sound more like an internal sticking issue??

Also, on a side note, i got a brand new full set of plastics for the bike, but apparently the only aftermarket front guard i can get to fit the bike (In Aus) is from a DRZ 400, which turned out to be a darker shade of yellow when it arrived! :moon:

Is it a good idea to paint plastic guards? I heard you can add a flex agent to the paint, but will that stop the paint cracking and peeling in the long run?

Thanks for reading! :moon:

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You could possibly have the idle (or fuel screw) turned too low and then have a binding of the throttle cables causing the idle to fluctuate. Check your cable routing to be sure the cables have slack. Many times when a bike is worked on, the cables are not re-routed properly. A clue would be if the idle gets faster if you turn the handlebars to the stops.

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Thanks for the responce Glenn.

Turning the bars doesnt seem to affect the idle and as far as i can tell the cable has plenty of slack.

When the bike is idling normally, it sounds like it idling at a high enough RPM, it doesnt sound like it's struggling, that is untill it coughs and then the idle starts to rise.

Also, i dunno if it makes any difference, but the guy who owned it before me has modded the airbox. He's cut a hole around 2 inchs wide in the top of the box... im not sure how this would affect the tune. From what i can see it still has the standard air filter in there aswell.

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The 2" wide hole could be where the snorkel lived and the PO removed it. Removing the snorkel does not have an impact on jetting, but if the hole you are referring to is in conjunction with the snorkel hole, your jetting will be a little too lean if stock.

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This is definately a hole thats been cut (jagged edges), its on the kickstart side of the airbox almost exactly on the edge where the side and the top of the airbox meets. I havent actually looked to see if the snorkle has been removed.

If it is the case that the snorkle has been removed and the additional hole has been added to the airbox, is it likely to cause the symptoms that im dealing with at the moment?

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Sounds like a gummed up carb to me.

You need to take it out and clean it. no shortcuts. Focus on the pilot screw.

2 years ago I left some treated gas with stabilizer in the float bowl over winter and it behaved the same way. Last year I drained the carb and it was fine after winter. There is still snow on the ground here.

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id try turning out the fuel screw out it sounds like its popping thru the carb and the popping on decel sounds like the pilots running a little lean

Try turning the fuel screw out 1/4 - 3/4 turns

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Thanks for the replies fellas, atleast i have a fair idea whats causing it now.

Can anybody shed some light on whether i should get my front guard painted or not?

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I have a Dr 250 which is almost 100% the same with your bike.These DR or DRZ have direct lifted carb.They are strong but sucks at idle speed.

I put another carb from Honda XL 250 Degree on.It's perfect now. Very low rpm idle.

Try another carb then !

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I had a 2003 DRZ250 that did the same thing

The only thing that made it better was to clean out the carb & all of it's little passages:smirk:

Lots of GUMOUT & Compressed Air later, only then was I able to get the adjustments mentioned above to work

As to the popping on decel....well, some of this is normal with these single cylinder 4-strokes, but a lot of it is not right:eek:

again....clean out the carb jetting circuits, especially the pilot & go from there

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yeah it sounds alot like a lean jetting situation. The thumb screw on the kick start side only adjusts the idle revs. the idle mixture screw is in a pig of a spot at the bottom of the carby, roughly where the starter motor is. You cant get a screw driver in and tune it while the carb is on the bike... which ruins standard jetting practice.

But you will find a quick clean out of the carb, maybe turning that annoying mixture screw about 1 turn further out should make it run a bit better.

Another thing that can cause an idle that rises and cuts out like that can be a worn slide, it can suck extra air thru making the mixture a bit leaner. But try carby cleaner and idle mixture screw richer first up.

PS I'm hoping to take my idle mixture screw into a boike shop one day this week to see if there is one available that matches up and has a thumb screw design instead of a screw driver design, should make tuning much easier.

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Thanks for the replies fellas.

The shop i bought the bike from cleaned the carb out when they bought it, or so they tell me. I took it back to them around a week or so ago so they could have a look and they definately think it's running lean.

When the bike it idling and you give it a quick rev (full throttle) it hesitates, so it's not getting enough fuel.

I think the problem has come about because the airbox has been modded (hole cut in the side of it) and the carb was never tweaked to take into account the extra air flow.

The guy was gonna adjust the pilot screw for me while i was there, but because i rode the bike to the shop, the exhaust was hot and he couldn't get at the screw.

I'll get the bike out again this weekend and have a go at adjusting it myself. 1/4 - 1/2 turns out will probably sort out the issue... well i hope so anyway. :thumbsup:

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I drilled and tapped a hole in the top of my pilot screw and screwed in a 1/2 in round home made thumb screw.:lol: Works good. :thumbsup: Now I can adjust it while the carb is on the bike. :usa:

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have you raised the needle one notch? sounds like the mid-range needs some help too when you give it thottle. the dealer probably won't do that unless your EPA rules are kinder in AUS.

is your bike road legal or a dirt model? if dirt only, after you get the carb cleaned/adjusted properly, it helps to run the carb dry before you store it. not sure why but my '01 doesn't like sitting for any length of time with fuel in the carb even with sta-bil.

i turn on the fuel, wait about a minute, choke it and turn the throttle 4 times and it starts on the first try even when it's cold. the routine kind of sucks but i've learned to live with it. saves wear and tear on the battery too.

bol,

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I just bought a '05 drz250 and it wouldn't idle down right and a little weak all around, so I did several things. Some intentional and some just as a matter of properly resetting things. I bought the dynojet kit thru the local dealer. I thought I was getting all new jetting parts, but it was just a new needle and several main jets. After you remove the carb once and leave the air filter connecting tube off, it's easy to remove again. I ended up doing this about 4 times to get the right main jet. The instructions said start with blah blah, but it was wrong.

I had cut a big hole in the top of the air box and drilled 4 3/8" holes in the muffler baffle and ground the weld inside at the header bolts. So I figured the instructions would be wrong.

The one thing I did that probably helped the idle most was adjusting throttle cables correctly. It had been terribly slack on the pull back side.

Anyway, the little bitch runs pretty good now. Can't match my WR, but lots less bucks too.

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