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New to me wr250f, need some quick advice

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So I picked up a 2003 wr250f. bike is in pretty nice shape, but it has been in a garage for 3 years, and needs some maintenance.

My question is this

Should I take it to a dealer for a tune up? or should I do it myself?

I rebuilt a 1980 yz 125, and rebuilt cars, I have technical abilities.

This bike starts perfectly when choke is on, dies as soon as choke is taken off. Carb is probably gummed up

Do I need to worry about the valves? What else should I check?

I just want to know what you guys think. Dealers are about 2 - 3 weeks behind right now, I would like to maybe get this going sooner. But i also want a reliable bike for trailing this summer..

Thanks for your time

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No way!! Do it yourself!!! First things first and get yourself a manual. You can download them free from a link on this site just do a search. Tear down your carb, clean it really well and replace the pilot jet. They get really plugged up and very difficult to clean. Adjust your mixture screw and you should be good. Might be a good idea to check your valves and change the oil and filter if you don't know when it was done last.

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So I picked up a 2003 wr250f. bike is in pretty nice shape, but it has been in a garage for 3 years, and needs some maintenance.

My question is this

Should I take it to a dealer for a tune up? or should I do it myself?

I rebuilt a 1980 yz 125, and rebuilt cars, I have technical abilities.

This bike starts perfectly when choke is on, dies as soon as choke is taken off. Carb is probably gummed up

Do I need to worry about the valves? What else should I check?

I just want to know what you guys think. Dealers are about 2 - 3 weeks behind right now, I would like to maybe get this going sooner. But i also want a reliable bike for trailing this summer..

Thanks for your time

Congrats on the new ride !!

Your bike running only with the choke on is definitely a sign of a carb with some varnish in it. Swede is dead on with his comment about the pilot jet. Every time I've taken one out of mothballs, it will run only with the choke on and usually the engine RPM's will hang about mid range when you blip the throttle. You have to kill the engine and restart to get it to idle again.

I just cleaned up four carbs over the weekend. For the first time ever I used Simple Green and I have to say I was impressed with the results.

Strip the carb, drop in it a plastic container big enough to hold all the parts and give you a little working/handling room, dump in a bottle of Simple Green and add enough water to completely cover the carb and parts.

Let it sit overnight, rinse thoroughly with clean water until all the Simple Green is off it, blow it out and dry it with compressed air - good to go.

I've always used kerosene in a parts washer in the past, but read a post here at TT about someone using Simple Green. I didn't want to wait the estimated 3 weeks for the rebuild kit to arrive so I decided to try it.

It was the smoothest and easiest carb cleanup I've ever done.

I got to liking the results so much, I tore into the other bikes and cleaned their carbs up too.

Take a good look at the tires. If they are even a little dry rotted or cracked, trust me when I tell you from BTDT experience they will literally fall apart on you at the most inopportune time. If they're just a little brown with a layer of dust on them, clean all that off and look closely at the bead. Flex it a little, if you seen any cracks at all and you're going to run a woods loop that is any longer than you would like to push, replace it.

Other than that, fresh gas, an oil change, drain and flush the rads and fill with new coolant. You might also take a good look at your fork seals. They're probably good, but, not something you want to overlook.

One other thing, that you might run into. Sometimes when a bike sits up for a while, the air filter will break down and disintegrate. So, pull the air filter and just toss it unless it looks perfect. You'll know if it's really bad when you touch it because it will stick to your fingers in chunks like cotton candy and fall apart as you are trying to get it out of the air box.

If the air filter is like this, definitely tank your carb overnight as you can bet those little chunks of deteriorated foam are what's clogging up your carb. Run your (clean) hands around the intake bell to make sure none of that got past the carb.

I know, jets are small, way smaller than a chunk of foam, but when a filter gets to that point it breaks down to something about the size of grains of sand and those will definitely get sucked into the carb and get blown thru to the intake... at least until the rest of it gets clogged up enough to not allow anything to pass.

Other than these things, ride it like you stole it and enjoy :thumbsup:

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Who was it that said to soak your carb and parts in Pine Sol? Anyways soak in Pine Sol overnight works miracles

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Thanks for all the advice,

The Air filter is dirty, but seems to be in decent shape.

The rear tire is pretty much done, I definitely will need a new one shortly, just doing a bit of research before I order one up.

I have never heard of using Simple Green to clean a carb, I have a new container of that. When I rebuilt my 125 carb i soaked everything in Seafoam. I was pretty amazed at how that worked. So instead of trying to clean up the pilot jet, I should just replace it?

I would like to check the valves while I am at it all. That seems like a bit of a interesting job to do. I guess that is the most intimidating part of it all. I will do a bit more research on that.

The bike came with the full manual, so I have the tear down of the bike, that will help out a lot.

Thanks for the advice. I might just tear into it this weekend and hopefully have it all back together and running.

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Well I took your advice, I ripped into the bike tonight. Valves check out, all within spec.

The carb is another story, i dont know how long the gas was sitting in there, but it is gummed up and pretty screwed up. I am going to carefully take it apart tomorrow and soak it and clean it up. If that goes well I should be out riding this weekend. Providing we dont get more rain/snow

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The pilot jet may be hard to clean so it is a lot easier to replace it. When I went to the store for another pilot I bought a few sizes bigger and smaller so I could play around with the settings

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All you need to do is take the bowl off, take the jets out, remove the slide and needle. You shouldn't have to completely take the carb apart, and many would advise against it.

If the bowl is badly corroded, you can use some industrial purple degreaser on it. I'm pretty sure you can get it at home depot. Be careful with this stuff, it's pretty nasty. I'd wear rubber gloves, it will burn your hands after prolonged contact and stings like hell if you get it in a cut. Also use it in a well ventilated area as a good whiff of it will make you cough.

Anyway, you're probably asking why would I ever use this stuff? Well, it's a caustic so it will slightly eat the aluminum, especially the corroded areas. Squirt some in the bowl and go at it for 30 seconds to a minute with a plastic brush. Jab, scrub, whatever and then rinse it out with water. Should look a lot better.

For the jets, a soak in CLR sometimes helps. Compressed air helps, too just don't blast it on your skin for too long especially when your hands are all pruny from cleaning your carb, or you have a cut on your hand (now how would that happen from working on a vehicle???) Little air bubbles in your blood are not fun... I've heard of guys using fishing line to jab at the gunk to get it out of the little hole. I've had a jet off an old bike so clogged I had to go at it with a mini drill index, just make sure you aren't making the hole bigger! Or you could just pick up a new jet and save yourself the effort they're like $5 I just got one today. How much is your time worth?

Once you get the carb cleaned, run the fuel screw all the way in, then back out two turns. That should get the engine started and you can mess with the fuel screw to get the idle mixture just right from there. I'd recommend an extended fuel screw, trust me you'll want it! I got one of the ThumperTalk ones, but I didn't like that annoyingly sharp pin for turning it. I ended up making an knurled aluminum cap for it and it is really nice now. The Zip Ty one looks very similar to mine so it should be nice.

Good valves, fresh gas, fresh oil, suspension OK, carb clean, tires good... Go ride!

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When I dunk the carb, is it ok to keep the throttle position sensor on? The manual says to only loosen the screw when replacing the sensor. So i dont want to mess with that if i am not supposed to.

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I've heard you don't want to take it off unless you know you can get it perfectly aligned when re installing. It's pretty important.

It's sealed so you should be fine... Do you really need to clean the top of the carb? I've never seen one that's dirty on the top before, usually it's just the bowl. You could stand it upright in a container with not enough fluid to reach that high if you want. Usually I get by with just spritzing some soap up in the bottom part and going at it with a brush, rinse under the sink and it should be nice and clean. Again, usually it's the bowl, jets and float that need it the most.

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If you have a manual then most definitely take the time to become an expert on your own bike. The money you save could very well pay for your next Yamaha down the road. Have fun!

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Well i got the bike back together yesterday, and went for a quick rip. Bike runs great except at idle. It is has a very high idle and I cant seem to tune it down. I found a great article on here from William1 that explains how to set the fuel screw, so I am going to try that. I am sure that is all that is wrong. I am also going to get a new pilot jet and fuel screw. When i went to the local dealer to get them the guy was a moron, and of no help. So I will have to try to get them from some place else.

Thanks for all your help

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That's good to hear! Definitely follow William's instructions to set the pilot circuit, he knows a ton! Get an extended fuel screw with a handy knob, like the zipty one, or one of the ones that has a tube. You will be so happy you did!

You probably don't have to go to a yamaha specific dealer, lots of bikes use the Kiehin FCR MX carb, so a lot of dealers should have the jets. If the guy can't get you a jet...:smirk:

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I think it's a 40p and 175m 70L in U.S. In Canada it's 40p and 170m 90L. That's what my manual says for my 04 but of course that all changes after you do all the mods

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40 pilot? Man, you may need one larger, especially after doing some of the free mods. My YZ is running a 48 right now and it's perfect. If it was me though, I'd get the 40 (maybe 43) and follow William's advice on setting the mixture. Then you'll know for sure what you need. Remember, more than three turns and you should go up one.

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I read a very interesting post by William recently where he was saying that if you open up the airbox (give it more flow) then it can reduce the suction and therefore require larger jetting. Even though the jetting is larger, it might not necessarily be richer because there is less suction and fuel flow will remain the same.

I've read that the WR's airbox is pretty choked up when stock, so opening it up will most likely require bigger jetting than stock, even if no other mods are done. That would also explain why it needs only a 40p stock and isn't way too lean.

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i don't have any mods done to the bike. I did see there was a paper in the manual the kid gave me on how to do the Grey Wire mod. As far as I can tell the air box, and exhaust is all still stock. I have ordered a few jets and a fuel screw. I will get it running like this, then worry about doing mods. I am happy with the power it has right now.

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