WR250F O-Ring Mod

[commguy23]

When I installed the JD Jet Kit last weekend I used the thin o-ring to be safe, since I ride only trails. I want some more power during acceleration but I lost the other thick o ring that came with the kit. Is this something I can pick up at an ACE hardware store?

This is on an 07 WR, also has the baffle and snorkel removed, #40 leak jet, 180 main, stock pilot. Top speed on pavement is about 56mph.

Edited April 14, 2013 by commguy23

[speedtoad]

Yes. But you shouldn't need it. The o-ring mod is for curing hesitation during sudden acceration. If your bike has this problem its because the carb is set up wrong.

[William1]

Plumbers oring, it is a #78

It will not give you more power it only helps with a bog, if you have it.

Did you do the grey wire mod? 180 main is kind of big too.

[commguy23]

Thanks guys. I tried the grey wire mod and had a problem with hitting the throttle hard, like to pull up the front wheel in second gear for example. I didn't have this problem until I removed the grey wire. I reconnected it and the problem went away. I mean I still can't peg the throttle as much as I would like to but its definitely better off without that mod.

[William1]

Did you remove the throttle stop and replace it with the YZ one?

[commguy23]

Did you remove the throttle stop and replace it with the YZ one?

Not yet, I ordered the screw Friday though. I thought the screw only affects more of top speed, since I'm not twisting the throttle all the way when I'm in 1st or 2nd gear.

Edited April 15, 2013 by commguy23

[William1]

Stock stop screw, you get about 2/3~3/4 throttle

The Gray wire just softens the 'hit' a little, almsot imperceptable. Some cannot even tell. On my WR, I put in a switch. In the 'Gray wire connected' setting when in mud/sloppy conditions it gives more 'bite'. Otherwise, the crisper throttle reponse is prefered in the 'YZ' setting.

[commguy23]

Stock stop screw, you get about 2/3~3/4 throttle

The Gray wire just softens the 'hit' a little, almsot imperceptable. Some cannot even tell. On my WR, I put in a switch. In the 'Gray wire connected' setting when in mud/sloppy conditions it gives more 'bite'. Otherwise, the crisper throttle reponse is prefered in the 'YZ' setting.

Hmm... it definitly made my throttle response worse when I pulled it, since every time I tried to peg the throttle to wheelie (without the clutch) it would bog down to no power. I put the wire back in and didn't have the issue. Maybe I pulled the wrong one.

As for the O-ring, you say a #78 plumbers oring, I am going to go pick one up at ACE hardware today, I just want to verify that this is the THICK oring in the JD jet kit instructions correct? Because it comes with 2 of them, a thin and a thick oring. Thanks again

[William1]

You may of pulled the wrong one. The gray wire cannot cause a bog, it makes the engine bark more sharpley.

Yes, the #78 is the thick oring. If you cannot get a thick one, get two thinner ones. DO NOT TOUCH THE ADJUSTMENT SCREW!!!!!

[NateInRoundRockTX]

You may of pulled the wrong one. The gray wire cannot cause a bog, it makes the engine bark more sharpley.

Yes, the #78 is the thick oring. If you cannot get a thick one, get two thinner ones. DO NOT TOUCH THE ADJUSTMENT SCREW!!!!!

I have a confession to make William1, I messed with the adjustment screw and did not make note of how many turns out it was. I am wondering how many turns out from snug closed that you are or anybody else. I have been having carb problems with my 2003 WR250F and can't get it to stay at an idle without dieing out. I replaced the pilot jet and have done many mods such as adding on a YZ250F stock exhaust, YZ throttle stop, grey wire mod, air box mod, new piston/rings/cam chain, the JD Jetting kit along with the big o-ring mod and adding the #55 leak jet. I called JD Jetting and told them of my mods awhile back and they said to run the blue needle in #5 position with #185 main jet. I am in central Texas region with my riding temperature from 60 to 110 degrees and my elevation around 500 to 1,200 feet. Stock main jet is a 185 and that is what JD also sent in the kit. My carb has been thoroughly cleaned all orifices and my valves clearances are all in spec. New plug and air filter has been added although it didn't need it. I wanted to make sure that that was not an issue. I replaced that inferior plastic hot start plunger that goes to the carb with a quality metal one. I replaced my cold start plunger with a new one and replaced the float and needle. I noticed the air cut valve diaphragm was bad looking so I replaced that. Added a Moose fuel screw. A leak down test was performed and that was not an issue at all. My question would be to anybody out there for me to know where to get a baseline starting point for my location riding temp/elevation with the mods I've done,

1.How many turns out is recommended on that screw where the o-ring mod is done?

2.What color needle and clip position?

3.What jets are recommended?

4.Why do people drink crappy-ass Bud Light?

[William1]

Being honest and upfront with all data is the only way anyone can help.

The method for resetting the AP timing screw is in your manual.

Here is the condensed version.

Resetting the AP timing to 'stock'

Method #1 - Most accurate

Turn the idle speed screw so the slide is completely closed (count the turns and note it) .

Turn the throttle wheel, raise the slide, slip a .8mm drill blank under the slide, release the throttle wheel, pinning the blank.

Turn the AP timing screw so the play just barely goes away.

Remove the drill blank, reset the idle speed to where it was.

Fine adjust the AP timing screw by test riding, turning in 1/2 turn increments to where the bog is just gone. Should be less than 2 turns, if at all.

Method #2 Not as accurate

Back out the idle speed knob (count the turns and note it) until the screw end of the idle speed cable is no longer touching the throttle wheel - Throttle cables may have to be fully lossened.

Ensure the slide has bottomed out on the carb bore'

Set the timing gap between the cam and the screw to be .010"

Reset the idle speed per your notes, reset the throttle cables if loosened.

Whatever method you follow, do not second guess it. Follow it EXACTLY. Once done, ride your bike. Get it fully heated up. Ride normal, if you have any bog (only when riding normal) then turn the screw 1/2 turn CCW. Retest. If the bog is gone., You are done, if it is better but still there, turn it another 1/2 turn. If it was worse, turn it CW.

Base jetting where you are with a JD needle is Blue, clip three or two (from the top/flat),

42 pilot though you need to test and check

Fuel screw settings in the 'book' are recommended starting points. Every bike is different, as is the temp and altitude. Set the screw according to this method. Do it with the bike fully heated up.

Gently turn the screw all the way in. Now back it out two turns. Start the bike and fully warm it up, go for a 10 minute ride. Set the idle to speed to 1,500~1,800 RPM as best you can (I know, without a tach this is tough, just set it to were it idles relatively smoothly). Once warmed, slow the idle to the lowest possible speed.

*** When turning the fuel screw, keep an accurate 'count' of the amount you are turning it and record it in case you have to reset it for some reason. Makes life easier when you can just set it from notes Vs. going through the procedure again.***

Turn the screw in until the idle becomes rough or the bike stalls.

if it stalled, open the screw about 1/4 more turn. Restart it and slowly screw it in till you can just perceive a change.

If the screw can be turned all the way in and the bike still idles perfectly and does not stall, then you need to go down a size in pilot jet.

Now very slowly, open the fuel screw till the idle is smooth. Blip the throttle, let the bike return to an idle, wait say ten seconds. Confirm it is the same smooth idle.

If the screw has to be opened more than 3 turns to get a smooth idle, you need to go up a size in pilot jet.

If you find it does not stall with the larger jet but has to be open more than three turns with the smaller pilot jet, put the larger one in and set the fuel screw at 1/2 turn.

If the idle speed increased, adjust the idle speed knob to return the bike to a real slow idle speed. You must then re-visit the fuel screw. Keep doing this till the fuel screw is opened just enough to provide a nice steady idle at the lowest possible RPM. Once this is done, increase the idle speed to the normal one for your bike, typically about 1,850 rpm, but go by the spec in your manual.

[gatorfan]

1) What exactly does the O-ring mod do?

2) I did all other parts of the JD kit, is the O-ring a good idea then?

3) Do I access O-ring the same place I accessed the throttle stop screw, by removing that side plate on the carb? 

[YZEtc]

1) What exactly does the O-ring mod do?

2) I did all other parts of the JD kit, is the O-ring a good idea then?

3) Do I access O-ring the same place I accessed the throttle stop screw, by removing that side plate on the carb? 

 

1) Ties the two accelerator pump lever together via a thick rubber O-ring to help force fuel through the accelerator pump squirt nozzle.

2) If you discover your bike has an annoying hesitation when suddenly opening the throttle while riding it (not while stopped).

3) Yes.

[firstnewbike]

my 06 wr250 the gray wire mod what I noticed is the bike revs up faster , I have mine on a switch also if you have it on a switch and want to flip the switch while moving you have to turn the bike off and on because the ignition only looks at the wire connection when first turned on, so you pull the clutch in and turn bike off n of while rolling. You should have more top speed than that,  I have geared my bike lower 'dropped on tooth on the front sprocket 'it helps a lot when riding single track, and I can do 55+ in top gear n part throttle

[gatorfan]

1) Ties the two accelerator pump lever together via a thick rubber O-ring to help force fuel through the accelerator pump squirt nozzle.

2) If you discover your bike has an annoying hesitation when suddenly opening the throttle while riding it (not while stopped).

3) Yes.

 

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