newbie questions


13 replies to this topic
  • arcboy

Posted November 24, 2007 - 08:51 AM

#1

I have searched a bunch and just want to make sure on some things.

01 WR426

If I do the grey wire mod do I have to rejet it?

I do a lot of street riding, due to me SM conversion, and want to get rid of the miss at constant speeds. So do I adjust the TPS or just disconnect it for street use and reconnect it for the dirt? I don't have a multimeter so can I just adust it a little at a time.

I will attach a pic later of what I am guessing is the leak jet but not sure(the red knob with numbers 1-4 on the bottom of the carb).

I am not as concerned with getting more performance as I am worried about the reliability, so by doing such mods will I risk anything?

  • MaxPower

Posted November 24, 2007 - 09:35 AM

#2

[COLOR="SeaGreen"]that isnt a leak jet
Thats the air screw
I dont know if your bike had leak jet. I think for your model bike they did a BK mod. Do a search. Do a search anyway for your carb settings.
As far as the TPS, my bike did miss. I went richer on my needle and it went away totally. It was missing bad too.
I dont feel you will have to rejet cutting the gray wire. As far as reliablitly, change your oil alot.What gearing do you have on your bike? [/COLOR]

  • arcboy

Posted November 24, 2007 - 12:47 PM

#3

Posted Image

So red knob is a air screw? How does it affect the bike?

You sent richer on the main needle? If I screw out that red knob, it looks just like a main needle with the E-clip with different slots for adjustment.

My gearing is 15/47.

No rejetting by cutting the gray wire, why do other people do it?

  • clark4131

Posted November 24, 2007 - 04:30 PM

#4

You really need to spend some time reading the stickies. There is no air screw on a 4-stroke carb. The red knob is an aftermarket fuel screw which is used to fine tune the jetting once it's set properly. If you pull it out, it should have a spring, small metal washer and a small black rubber o-ring. If you pulled the screw all the way out and they weren't there, there's a good chance that they've gone missing and your bike will never run properly without replacing them. At this point, I would suggest pulling the carb and seeing what you have in there. Give it a good cleaning as well...SC

  • arcboy

Posted November 24, 2007 - 04:44 PM

#5

You really need to spend some time reading the stickies. There is no air screw on a 4-stroke carb. The red knob is an aftermarket fuel screw which is used to fine tune the jetting once it's set properly. If you pull it out, it should have a spring, small metal washer and a small black rubber o-ring. If you pulled the screw all the way out and they weren't there, there's a good chance that they've gone missing and your bike will never run properly without replacing them. At this point, I would suggest pulling the carb and seeing what you have in there. Give it a good cleaning as well...SC


I have read a lot of the FAQ's and stickies but I like pics and I don't want to take someones write ups the wrong way. It seems as if there a few different opinions on what is reliable or not. Right now I just want to know about the gray wire and how do I know if the TPS and the knob are adjusted properly.

  • clark4131

Posted November 24, 2007 - 05:10 PM

#6

I have read a lot of the FAQ's and stickies but I like pics and I don't want to take someones write ups the wrong way. It seems as if there a few different opinions on what is reliable or not. Right now I just want to know about the gray wire and how do I know if the TPS and the knob are adjusted properly.


From the FAQ:

Q: Why cut/disconnect the grey wire?
A: The grey wire mod goes hand in hand with the throttle stop mod. As you are now able to use the entire range of the throttle with a shorter stop, the ignition map must be changed to accommodate the increase in fuel delivery. Removing the grey wire connection does this.

Q: Okay, so where is the Grey Wire?
A: On the '06 and older, steel framed WR's, it's on the right side of the frame under the tank in a 6-pin connector. On the '07-up, it's under the left side panel in the 6-pin connector. The best way to do it is to push the wire out of the connector using a small slotted screwdriver and then tape off the ends. That way you can always put it back together if you want, though I don't know why you'd want to.

Q: Why does my WR seem to miss when I hold the throttle steady in the 1/4 to 1/2 turn range?
A: That's your TPS (Throttle Position Sensor) doing it's job. Dirt bikes don't normally run with a steady throttle off road and they weren't designed too. Unplug it and see if the "miss" goes away. If so, then you know. You can also follow the procedure for checking the TPS voltage in the manual. It's extremely simple if you have a multimeter and some folks have found that it is set funky from the factory. Once properly adjusted, the problem goes away


From ThumperFAQ:

When the pilot circuit is jetted properly, starting the bike should not be a problem. You will need the choke to start cold and it won't run well off of choke for 30 seconds or so. When hot you will probably need the hot start. The bike should idles smoothly and have no hesitation of idle and minimal backfiring on deceleration. For more info about the pilot screw, see this article that recently appeared in Motocross Action Magazine.

Setting the Fuel Screw / Pilot Jet "by Ear"

Adjust the idle with the black knob until it is too fast. Then adjust it back down until it is around 1900-2000 RPM or if you don't have a tachometer (see below) until it sounds just a little high.


Before you start adjusting, count the turns required to tighten it up lightly.

Then start the bike with the slightly elevated idle and turn it out 1/4 turn, 1/2 turn, 3/4 turn and so on until you get to 2 turns. Listen for best RPM and best response to a quick 1/4 turn tweak of the throttle at each position of the fuel screw.

Now turn back in 1/4 turn at a time doing the same thing. By now you should have been able to distinguish the speed of the idle and the responsiveness to tweaking the throttle.

If it gets better between 3/4 and 2 turns out, set it at the best location and leave the rest of the pilot circuit alone.

If it is getting better turning it in or is best less than 3/4 turns out, replace the pilot jet with a smaller one and go through this procedure again.

If it is getting better as you turn it out or best at more than 2 turns out, replace the pilot jet with a larger one and go through this procedure again.

Setting Fuel Screw / Pilot Jet with Tachometer

Warm the bike up by riding about 10 minutes. Place it on a stand, have it idling. If you have a fan, direct it into the radiators (A YZF will start to boil out if you take too long to do this, WRFs have a nice catch tank).

Turn the fuel screw 1 1/2 turns out. Read the RPM for about 10 seconds (on my tachometer, cause it bounces around). If the avg RPM is not between 1700 and 1900, adjust to about 1800 with idle screw knob on carburetor Write down average RPM.

Turn the fuel screw 1/2 turn out. Write down the average RPM.

Turn the screw 3 turns out. Write down the average RPM.

If #2 is greater than #3 or #4, you have the right pilot jet. Usually the difference will only be 50 to 100 RPM. Go on to step #7.

If #3 is greatest, you need less fuel. Install the next smallest number pilot jet. Go to step #3 and repeat.

If #4 is greatest, you need more fuel. Install the next largest number pilot jet. Go to step #3 and repeat.

Adjust the fuel screw in 1/4 turn increments around 1 1/2 turns out and find the maximum RPM fuel screw position. If the idle is now above 1900 RPM, turn it down to be in spec.

If you get a little deceleration backfiring on closed throttle, try adding another 1/4 turn out. Remember you will need to redo this if the altitude or temperature changes significantly


If you still need pics, you're SOL...SC

  • arcboy

Posted November 24, 2007 - 05:39 PM

#7

Sorry for all the retarded sounding questions but I just want to be very clear.

"Removing the grey wire connection does this". Does what? Automatically change the ignition map?

I don't have a multimeter so is it possible to adjust the TPS without one? And by adjusting it some guys are saying it does't do well in trails. Seems to be conflicting comments about just disconneting it for the street and reconnecting it for trails.

According to setting the fuel screw/pilot jet I don't have a problem because my bike starts in one kick everytime no matter what the temp. It does backfire occasionally but very few times. I guess I could turn the fuel screw out a 1/4 at a time until it stops backfiring all together.

No pics needed so far:thumbsup:

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  • clark4131

Posted November 24, 2007 - 07:02 PM

#8

The WR CDI essentially has two ignition maps in it, one aggressive (YZ map), one not so much. The YZ map is ideal for use after the throttle stop is shortened as it will compensate for the increased fuel now available from a fully functional throttle. Disconnecting the grey wire activates that map...SC

  • arcboy

Posted November 25, 2007 - 10:31 AM

#9

Beautiful! Thanks for the clarification!

  • arcboy

Posted November 25, 2007 - 10:33 AM

#10

The WR CDI essentially has two ignition maps in it, one aggressive (YZ map), one not so much. The YZ map is ideal for use after the throttle stop is shortened as it will compensate for the increased fuel now available from a fully functional throttle. Disconnecting the grey wire activates that map...SC


What about the TPS adjustment? Sorry to keep bothering you with stupid little questions.

  • clark4131

Posted November 25, 2007 - 10:53 AM

#11

What about the TPS adjustment? Sorry to keep bothering you with stupid little questions.


The procedure is in the manual...with pics...SC

  • WR_Dave

Posted November 25, 2007 - 10:54 AM

#12

You will only be accurate with the TPS adjustment if you have a digital multimeter to check the setting. You can pick one up for around $10- $15 at a hardware or auto parts store. Or just unplug the TPS while road riding, it doesn't hurt anything. WR Dave.

  • Nostalgic

Posted November 25, 2007 - 11:26 AM

#13

arcboy, are you an Arckid fan by chance? Just curious and good like with everything!

  • arcboy

Posted December 25, 2007 - 08:02 AM

#14

arcboy, are you an Arckid fan by chance? Just curious and good like with everything!


Guess not because I don't know what arckid means.




 
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