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Old 04-30-2013, 02:04 PM   #31
browneye
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Looks like you have the gyter exhaust stinger too. I think I have the other one, forget who makes it. Promoto maybe?
Anyway, they are finicky to jet, worse than a 2-stroke. The good news is once you get them dialed you generally don't have to fuss with them. Makre sure to crack the bowl drain when it's gonna sit or our crappy fuel will plug the pilot within a couple of weeks.

I've never been a fan of JD Jetting, having found I do better getting my own needles and jets. But there's some merit to some of what he has. I thought I would save myself some headache when we got the '08 since changing jets is a royal PITA with the aluminum frame. But as usual his recommendations were way off, way too rich. I think I already posted a pic of the '08 with the white plastics, custom graphics, and black rims. Then sold it and got a '04 with a plate - whoot!!

You got the idle fuel screw with your kit, right? That provides some flexibility on the pilot circuit for elevation. We used to drop the main one for Sierra riding, anything over 7-8K feet.

Seems to me the 168 main works well with a 42 pilot, with the snorkel out and opened exhaust stinger. I think when I rejetted the current one I was out of 42 and had a 45 and I think it's too rich. I don't like the way it idles, seems like an air leak. I think I got it pretty dialed in last time out with the idle mix screw, probably closed it down some. Really need to get the smaller pilot though. I also think JD has a 175 or 180 main and mine woudn't run with that at all, just bogged on WOT. Back to stock and it ran right. I know the JD needle throws the main numbers all out of whack.

Can't recall what I did for a slide needle. There's a blue one and a red one right? Red for lower elevation? I think that's what we used on the first one. I must be running a stock needle on this one.

I'm sorry, it's been so long I can't remember. Maybe I have some specs written down somewhere.

The gray wire is the back near the voltage reg I think. Good instruction in the WR help files which I'm sure you've found, right? http://www.thumperfaq.com/index.htm I think if you cut the wrong one something else wouldn't work. All that does is put the ignition map to YZ spec. It does help though, you can get pretty good power out of them.

Really good info on jetting here: http://www.thumperfaq.com/jetting.htm

I need to do fork seals. Damn thing is so old the seals blew out last time. It doesn't get ridden much. My kid is finishing high school and is always too busy to go riding with us, the rest of the time I take the husky or the triumph. But I hang on to it for singletrack trail riding, although I'm getting to old for that shit anymore. When I sold the KTM I took the MT43 off it and put it on the WR. Does work really well, even in sand.

Oh, and valve adjust...last time I got the timing off one tooth and it wouldn't start. The auto-decompress doesn't work right when you do that. Otherwise they are easy to check and adjust and they need to be kept an eye on. Every 25 hours or so.



EDIT: Read your post again...if it's bogging on WOT throttle I bet you got a 175 or bigger main in there right? Drop down one and see what that does. I'll bet it cleans it up and you get a nice boost.
Also, if your accellerator pump isn't squirting enough that will do it. Opening the slide let's too much air in and it bogs. I'd check the main though, I've never really had trouble with the pump.
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Old 04-30-2013, 07:12 PM   #32
Adv Grifter
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Thanks for the ideas. Looks like my Gray wire is OK. Did not seem to make much difference that I could tell. On the muffler, I think I just took out the baffle, but ages ago, can't recall. Not too loud so OK with me. Snorkel is OFF.

I'm running a 170 main, but I broke it off () so went with the 160 JD provided, along with 3 or 4 other jets? (160, 170, 180 ... ) I had a few also. Two needles provided (Blue and Red as you said). I had another from other FCR Carbs. The Red one seems pretty good.

I do have the extended pilot fuel screw, really does help at altitude.
Glad to hear I'm not the only one who suffers tearing into this beast with its Alu frame fighting you the whole way. I remove the big Alu cross brace for access but still a pain.

You're right, I've clogged the Pilot jet several times. Sea Foam now lives in the fuel and does help to keep it running.

I did the Rubber O ring on the Accel pump, but no idea if the squirt duration is correct or aimed correctly. It takes forever to warm up and take full throttle.

I'll keep trying and fiddling. I need to buy a "new" 170, it seems to work best for my riding: between 3000 the 7000 ft. Needle clip position I'm just guessing on. At altitude I think leaner is better on the clip. (???)

I just wish there was a HARD AND FAST jetting guide the really worked. As you mentioned, the JD values made for TOO RICH running and bogging. Some said I needed a different Air Leak jet. I have no idea. The kit came with a leak jet ... why would JD send the wrong one?

Wish me luck ... and thanks again for helpful ideas.
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Old 04-30-2013, 08:27 PM   #33
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I was thinking the stock jet was a 168 and 42? I sure wouldn't run it leaner. If anything, same with the JD needle, or 170/172. I got best results from the stock 168. I'm also pretty sure JD says 175-180 for sea level but that was way too rich for mine.

The leak jet and acc pump are probly fine. Fine tune for good idle, crisp throttle, and clean wot with good pull. Should be easy to tell where it's lean or rich at a given throttle opening after some time riding it. This is where you either train your ear or get someone that can tell. I got really good at the 2-strokes, but the 4's are more difficult. The FCR carb is a good one though, easy to fine tune.

Seems to me a lot of guys use a YZF needle, start with it in the middle groove, adjust from there. Slide needle is 1/4-3/4 throttle, but the main will affect it too. That's why they're all a little different.

They are a fairly long-lived motor if you keep the oil fresh. Like every 15 hours or so, a filter every other change.
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Old 05-01-2013, 10:37 AM   #34
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Originally Posted by Adv Grifter View Post


I did the Rubber O ring on the Accel pump, but no idea if the squirt duration is correct or aimed correctly. It takes forever to warm up and take full throttle.


Mine does too. I think it has to do with the AP timing...This is on the list for me to check. My bike seems to be running real lean until it is fully warmed up. I think that adjusting the AP to squirt a little more, or earlier will be the key to fixing this.

I'm pretty sure your '07 requires different jetting than my '03 but right now I am running a 168 Main and a 40 PJ, needle in the middle position. This is for 6-12000 ft elevation. I'm going to leave it this way until I have the AP adjusted right.

It pulls great on WOT but there is a bog if I wack open the throttle too quickly at low RPMs...
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Old 05-03-2013, 01:36 PM   #35
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may 3rd in NWO canada, still getting snow....

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Old 05-03-2013, 05:39 PM   #36
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may 3rd in NWO canada, still getting snow....
Nice bike! I need to get some pictures of mine... We got snow on Tuesday, but it isn't sticking like it is up in your area probably.
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Old 05-03-2013, 06:11 PM   #37
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Nice bike! I need to get some pictures of mine... We got snow on Tuesday, but it isn't sticking like it is up in your area probably.
looks alot better with the street tires haha wish this thread was way more active
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Old 05-03-2013, 07:48 PM   #38
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What kind of miles you guys getting on these 250f's before rebuilds?
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Old 05-04-2013, 06:48 AM   #39
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What kind of miles you guys getting on these 250f's before rebuilds?
It's hard to say, or tell. I bought my 2003 WR250F from the original owner and the motor had never been opened. All five valves needed new shims, the piston rings were a little bit out of spec, but the piston and cylinder were in great shape and within spec.

I tried to gauge how many hours were on it by asking him about his riding style, how often he rode, and by how the bike looks. I would estimate, roughly, the bike had somewhere around 300-400 hours. Yes, that's a wide range but I have no way of telling exactly so that's the best I can do.

I went through the entire bike, except for the bottom end of the motor. I don't think the previous owner ever lubed any of the chassis bearings like the steering, linkage, and swing arm bearings so that all needed to be replaced. The lower rear shock bearing also needed to be replaced but the upper was in great shape. My suspension guy told me to keep an eye on the lower one, and that they need to be lubed up 2x as much as the linkage/swingarm bearings to keep from seizing up.

So, in the end, I replaced:

the piston, rings, cam chain, suspension bearings, steering bearings, adjusted valve clearences, a bent upper sub frame bolt, all fluids, and that's pretty much it.

This is what it needed after one person owning it for 10 years with minimal maintenance. The bike was ridden in Moab yearly, as well as in CO single track. I hope to get at least 5 years/300 hours (I'm pretty sure I will ride it twice as much as the PO did) before any other work, not taking into account normal maintenance. I suspect it will need a valve job (valve seats, new valves) before the piston and rings wear out. I'll have to keep an eye on the clearances. I guess normal rule of thumb is to shim the valves once, then when they tighten up again replace them and the seats to avoid any problems.

For how high these little engines rev, they are quite durable and can take some abuse as long as you maintain them. I'm very happy with mine.

For reference, I paid $1600 for mine and it came with a Colorado title, new tires, new chain and sprockets and a Scott's steering damper. I have a spreadsheet that I used to record all of the expenses made while bringing it back to and I think it was somewhere around $350 (I'll have to double check) total for all the parts.

In 10 years, $350 worth of parts needed to be replaced. I'd say that's pretty damn good considering the PO was the kind to take it to the dealer to have a battery replaced.

Oh, and good luck finding one this cheap in CO.
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Old 05-04-2013, 09:43 AM   #40
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Thanks for the comprehensive breakdown on your WR maintenance.

I have an '07 with low hours (under 100 hours) ... but I know I'm over due for some of the basic stuff. I have to check valves, they've never been done.

I will have a look at the shock linkage bearings. I know from years of dirt bikes that the lower linkage bearing is the first to rust out if not taken care with. (water crossings)
The good news is this WR has rarely crossed deep water ... or any water. I'm hoping the bearings are still all OK.

I will check steering head bearings too. I'm hoping the swing arm bearings can go another year or two. Nothing is squeaking ... which on my Enduro race bikes was always the Tell Tale that the bearings were rusting out or needed attention.

Also hoping the top end is still in good shape. This bike is not ridden hard, not raced. A real old man bike. Lots of oil changes.

Thanks again for all the good info!

I bought my WR based on one of the dirt bike magazines who raced and abused a WR250 for a couple seasons, even riding some kind of 24 hour endurance rally.
When they finally pulled it apart they found everything in remarkably good condition.

That did it for me. My kinda bike! Go WR250F!
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Old 05-04-2013, 06:55 PM   #41
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100 hours isn't too bad on a WR. I'd just check valves and go thru the bearings like you say. At 200 hours I would pull the top end or do a leak down test, check for ring wear, do the solvent test on the head. They are known to be pretty durable. If it's not hard to start the valves probly haven't moved.

My '07 KTM 250 needed rings at 100 hours, gap looked like it was missing a tooth. It was starting to use a little oil but started and ran fine. But they had soft rings and Wosner was a better replacement so that's what mine got. Valves never moved. Sold it at 135 hours.

If you ride a lot I'd put a moto-meter minder thingy that keeps track of time. Easier to keep track of things. If you keep the air filter clean it will probly go a really long time.
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Old 05-05-2013, 10:16 AM   #42
Adv Grifter
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Thanks for more tips Chris!
I think my '07 WR has an hour meter built in to the computer that comes with the bike. I have NO IDEA how that computer works. I use it to track mileage ... but I think somewhere it tracks running time.
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Old 05-06-2013, 02:34 PM   #43
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made a coolant overflow tank today, replacing the old pop bottle i had ziptied



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Old 05-06-2013, 03:46 PM   #44
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Wow...mad skillz.

I thought they all came with a coolant bottle under the left rear number plate?
Maybe that's a older one.
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Old 05-06-2013, 04:10 PM   #45
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Wow...mad skillz.

I thought they all came with a coolant bottle under the left rear number plate?
Maybe that's a older one.
replaced the stock coolant bottle with a tool kit,

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