00 wr jetting driving me crazy!!



19 replies to this topic
  • robman

Posted December 03, 2000 - 02:38 PM

#1

I'm loseing my mind trying to get that dead spot out ,I have stock pipe (uncorked)no lid on breather , twin air filter . I've tried #4 clip,#178 main,#45 pilot,I put the accelerator pump cover from factory R&D on the bottom of the carb (that cost $80) they said it was guaranteed to fix it but no luck and I've tried anything from 3/4 turn to 3 1/2 turns out , nothing works,( HELP! )

[This message has been edited by robman (edited 12-03-2000).]

  • robman

Posted December 03, 2000 - 07:24 PM

#2

Originally posted by robman:
I'm loseing my mind trying to get that dead spot out ,I have stock pipe (uncorked)no lid on breather , twin air filter . I've tried #4 clip,#178 main,#45 pilot,I put the accelerator pump cover from factory R&D on the bottom of the carb (that cost $80) they said it was guaranteed to fix it but no luck and I've tried anything from 3/4 turn to 3 1/2 turns out , nothing works,( HELP! )
any help would be great!

[This message has been edited by robman (edited 12-03-2000).]



  • Boit

Posted December 03, 2000 - 10:23 PM

#3

Rob: When you say "dead spot", do you mean a hesitation when you wick the throttle open suddenly? Does the engine spit, cough, hiccup...something along that line? Have you adjusted your valve lash? A tight valve could cause a dead spot. At what RPM would you describe this dead spot? Is it right off idle? If you can give as much detail as possible, you'll get tons of help here.

  • robman

Posted December 04, 2000 - 05:39 AM

#4

the dead spot is right off idle.when you wack the throttle it will die,like when your going to blip the throttle over a big root or log it will die or hesitate.

  • James_Dean

Posted December 04, 2000 - 08:09 AM

#5

robman,
When you put the pump on, did you test the accel pump to see if it squirts fuel? Could you see a strong flow?

Are you running the stock DRS needle? (US model)

Try turning the idle speed up a little if its not already. Expect around 2-3 turns on the pilot screw with the #45 pilot and DRS needle. Normally clip #3 or #4 would be good. It would be very odd to need a #5 clip, but it is still an option.

James

  • robman

Posted December 04, 2000 - 01:49 PM

#6

thanks james dean
I think I finally got most of it chased out,it has a #45 pilot and #3 clip at about 3 turns out , with the carb out the pump will squirt about a foot or so.

  • James_Dean

Posted December 04, 2000 - 02:37 PM

#7

The needle code is very important.

A DRS #3 is close to a DVR #5.
A DVR #3 is close to a DRS #1.

Which is it? US model DRS?

Usually I recommend replacing it with a DVP or EKP (YZ400 and YZ426 options) for better response.

Currently I'm running #48/100 air/1 turn/EKN#4/#175 and YZ400 exhaust in my '00WR. This is for 40F near sea level.

James

  • Clark_Mason

Posted December 04, 2000 - 05:40 PM

#8

I currently runing the following jetting on my 99WZ420 with excellent results

DVP #5 from the top

48 PJ

Fuel Screw at 1 3/8 turns out

182 Main jet

I'v also had excellent results with

EMN modified needle #4

48 Pj

Fuel Screw at 7/8

175 Main jet.

Hope this helps

Clark

  • robman

Posted December 04, 2000 - 06:22 PM

#9

I'm running the stock drs needle #3 clip.
I thought the needle had to do with 1/4 to full throtle, the dead spot is right off idle.

  • James_Dean

Posted December 04, 2000 - 08:07 PM

#10

When I tried the DRS#3 and #45 pilot jet it took about 3 1/2 turns out on the pilot screw to get the bog to reduce. The idle seemed too rich though. Then I switched to the needle choices and jetting mentioned above for myself and Clark.

A richer clip (#4)is not really a good choice for the DRS. It will be a little too rich at 1/4, just like you were thinking. Another needle might have been a different story (i.e. DVP#5).

James

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  • Boit

Posted December 04, 2000 - 10:20 PM

#11

Rob: You have two of the best jetting guys I've ever seen helping you with this. Won't take long now to get this solved... :)

  • olson_jr

Posted December 05, 2000 - 05:03 AM

#12

I noticed James Dean often suggests turning up the idle to help with the off idle hesitation. I have also noticed someone (?)suggests turning the throttle position sensor a little to correct the same problem.

I'm thinking turning up the idle and adjusting the TPS are during the same thing. They are changing the spark advance maping which maybe what is need (along with close jetting and accelerator pump ) to cure the hesitation.

Does anyone have any expertise in just what spark advance is doing when adjusting the TPS?

  • robman

Posted December 05, 2000 - 05:19 PM

#13

James dean

what difference does the DVP needle make over the stock DPS? and will it help the dead spot when you wack the throttle if I use the #$ or #5 clip?


[This message has been edited by robman (edited 12-05-2000).]

  • James_Dean

Posted December 05, 2000 - 08:13 PM

#14

DVP is richer at 0-1/4 throttle. The extra fuel helps smooth response. Experience shows that DRS is more lean than it needs to be by about 3 steps on the straight diameter.

(note the last letter) DRS-DVR-DVQ-DVP-DVN-DTM

There is a limit to how hard you can whack open the throttle. When it's right in real riding conditions (not on a stand at idle) it should never hesitate.

James

[This message has been edited by James Dean (edited 12-05-2000).]

  • robman

Posted December 06, 2000 - 03:29 PM

#15

thanks james I think i'll try the DVP needle.will I have to rejet again?and what clip# should I try first?

thank , rob

  • James_Dean

Posted December 06, 2000 - 08:01 PM

#16

robman,
Suggest you try DVP in clip #5 and while you're at it do the rest - #48 pilot and #100 pilot air, pilot screw about 1 turn. It should be sweet. :)

  • robman

Posted December 07, 2000 - 03:47 PM

#17

you wouldn't happen to have the dvp part # would you?
thanks alot for your help!

[This message has been edited by robman (edited 12-07-2000).]

  • James_Dean

Posted December 07, 2000 - 04:38 PM

#18

Yes,
5BE-14916-DP

  • Guest_Guest_*

Posted December 07, 2000 - 09:32 PM

#19

I have the same throttle response off the start... but it's not bad enough to kill it while I'm going... just when I start to take off at stop lights I have to give it extra gas to idle it up before I start to let out the clutch to keep it from stalling. It sounds like it's choking! everything is stock.. whats wrong? will it hurt anything?

  • James_Dean

Posted December 07, 2000 - 10:20 PM

#20

Joe,
Have you tried backing out the pilot screw a little at a time? It is probably too lean, the same problem as robman.

Has it fouled a plug ever?




 
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