Wow you guys were right about power


13 replies to this topic
  • treukauf

Posted March 27, 2005 - 06:19 PM

#1

I cut the throttle stop 23 mm on my 2000 wr400, cut the gray wire, and pulled out the smalle insert baffle. The bike rips. I'm very glad I bought it. The more I look at it the more I realize it has no miles. No paint rub marks near pegs, a true 700 mile bike with orig. tires. There is a pretty bad bog when you nail the gas at lower rpms, but I went through the carb and the guy had a 160 main jet, a 42 pilot, a 65 air jet(or whatever its called), and the stock odbrs in the 3 clip. I need to get it rejetted for my altitude so i'm thinking. 168 mj, 45 pilot, leave needle,and no clue about the air jet. Is the chrome outer insert meant to be removed or does it cause too much of a loss in back pressure( the one held in by three bolts not one). Noise doesn't matter for hillclimbing. on the ranch. Also does the bk mod solve the bog at low rpms pretty good? thanks

ps does the rear brakes on these things suck naturally. It seemed as if it really liked to lock up. rotor too small?

  • trikeflyer

Posted March 27, 2005 - 07:47 PM

#2

I just purchased a 98 wr400 with 700 miles too what elevation are you at and let me know what jetting you end up with
Jay

  • Dan_from_HB

Posted March 27, 2005 - 07:52 PM

#3

Get the JD jetting kit. It will allow you proper fuel/air mixture at all throttle settings. It will get rid of the bog. It will produce the power the engine was designed to output. It will start like it's supposed to. And you think it rips now? Wait until you try the proper needle! I'm going that way, and my WR already has jetting that's close to being right. But I don't have that JD needle yet. I wish I had paid more attention to the jetting threads here on TT when my bike was a little younger.
I would leave the chrome piece in. Not sure, but it probably keeps the guts in place.
The rear brake is a bit touchy. You will likely get somewhat used to it. The WR already has a heavier flywheel than the YZ, but you might consider one even heavier. It would help avoid lockup stalls. I've just gotten used to using lots of clutch under panic braking. After 4 years, I still stalled it today about 8 times in a 55 mile enduro. But damn does that thing haul the freight!

  • treukauf

Posted March 27, 2005 - 10:16 PM

#4

I wasn't sure if it was worth the 80 bucks or whatever. I'm sure i'll need more power in a day or two though lol. I might try running without that chrome piece when I climb to help hold the rpms. gotta love that noise.

  • bluethundaaaa

Posted March 28, 2005 - 02:27 PM

#5

I run a 68 main jet and the stock needle on clip 4. I rigged up my own fuel screw although it is not pretty it works well. I have done the BK mod and it has cleared up the off idle bog quite well now it only does it when it is cold and I don't know if I can ever get away from that. The BK mod is easy to do and well worth the time especially if your duration is >1 second.

  • martymart

Posted March 28, 2005 - 07:36 PM

#6

How can the bike have no rub marks on the frame near the pegs. I rode my bike once and I have absolutely no paint left.

  • treukauf

Posted March 28, 2005 - 09:58 PM

#7

really I suppose it has alot to do with the design and size of the boots. One side has an ity bity rub mark, but the other is perfect. The guy had two bikes and this one never got rode(his buddy sold him an 01 wr426 unbelievebly cheap so he saved this one). He says he changed the oil every 200 miles of easy trail, and he only had to change it 3 times. The foot pegs don't even show the usually dulled wear. I really didn't believe him at first. but the more I look the more I agree. The rear axle nut doesn't have a mark on it.

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  • Dan_from_HB

Posted March 29, 2005 - 09:00 AM

#8

I run a 68 main jet and the stock needle on clip 4. I rigged up my own fuel screw although it is not pretty it works well. I have done the BK mod and it has cleared up the off idle bog quite well now it only does it when it is cold and I don't know if I can ever get away from that. The BK mod is easy to do and well worth the time especially if your duration is >1 second.


I'm pretty sure the BK mod does not apply to the 2000 WR or later. There is an adjustment screw on the 2nd generation FCR carb that takes care of the accel pump timing. It's below the slide pulley on the right side of the carb.
Just adjust that to around 1/2 second duration or less and you're in the ballpark. If you have a bog after that, it's caused by something else.
Carb has to come off for this.
You can search TT for more details if you need them.
I'll post my jetting when I can dig out my notes.

  • bluethundaaaa

Posted March 29, 2005 - 09:21 AM

#9

I'm pretty sure the BK mod does not apply to the 2000 WR or later. There is an adjustment screw on the 2nd generation FCR carb that takes care of the accel pump timing. It's below the slide pulley on the right side of the carb.
Just adjust that to around 1/2 second duration or less and you're in the ballpark. If you have a bog after that, it's caused by something else.
Carb has to come off for this.
You can search TT for more details if you need them.
I'll post my jetting when I can dig out my notes.


thanks for clearing that up. I have an 02 WR426 and it did not have an adjustment screw so I had to do the bk mod.

  • Dan_from_HB

Posted March 29, 2005 - 08:38 PM

#10

thanks for clearing that up. I have an 02 WR426 and it did not have an adjustment screw so I had to do the bk mod.


Does that mean that the 02 bikes went back to the 1st generation FCR? That would be really strange.
Did you buy your 426 brand new?

  • ncmountainman

Posted March 30, 2005 - 05:55 AM

#11

I went through the carb and the guy had a 160 main jet, a 42 pilot, a 65 air jet(or whatever its called), and the stock odbrs in the 3 clip. I need to get it rejetted for my altitude so i'm thinking. 168 mj, 45 pilot, leave needle.

that sounds like a good start try the 4th clip and if you can find it go to a 100 pilot air jet. i"m not sure if it will fit but the 04 wr needle is awesome and only like $10. the BK mod is applicable to the 400 and people are getting good results on the older bikes with the p-38 and/or boyesen ap covers :naughty:

  • bluethundaaaa

Posted March 30, 2005 - 08:07 AM

#12

Does that mean that the 02 bikes went back to the 1st generation FCR? That would be really strange.
Did you buy your 426 brand new?


Yes I did buy it brand new in the crate. although it was 2004 when I bought it. However it did not have any adjustment for the duration on the accel pump. Mine was over 2.5 seconds. I had to drill the little tab on the carb, tap it and insert a screw with a spring. Now the duration is < 1 second. I believe that is the BK mod.

  • Dan_from_HB

Posted March 30, 2005 - 11:19 AM

#13

Yes I did buy it brand new in the crate. although it was 2004 when I bought it. However it did not have any adjustment for the duration on the accel pump. Mine was over 2.5 seconds. I had to drill the little tab on the carb, tap it and insert a screw with a spring. Now the duration is < 1 second. I believe that is the BK mod.


You're right. I spent some time researching the BK mod. I was under the impression it only applied to 98 and 99 bikes. It may well apply to all bikes EXCEPT the 98 and 99, according to other threads. I thought the 2nd generation of FCR had a standard screw that took care of the function of the BK mod. Maybe not.
I limited my squirt time to about 1/3 of a second simply with the existing timing screw, but it sounds as though that is really meant to adjust timing of the beginning of the squirt. I suspect that using that timing screw, like I did, to limit duration, will result in a late squirt.
Anyone know the true difference between the screw that is standard and the one that is added with the BK mod?

  • WRookie

Posted March 30, 2005 - 05:07 PM

#14

I'm pretty sure the BK mod does not apply to the 2000 WR or later. There is an adjustment screw on the 2nd generation FCR carb that takes care of the accel pump timing. It's below the slide pulley on the right side of the carb.
Just adjust that to around 1/2 second duration or less and you're in the ballpark. If you have a bog after that, it's caused by something else.
Carb has to come off for this.
You can search TT for more details if you need them.
I'll post my jetting when I can dig out my notes.


The screw you point out tunes the beginning of the squirt so it misses the slide. You still can do the BK mod to control squirt duration.




 
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