WR426 Jetting



8 replies to this topic
  • Jason_Foslien

Posted March 06, 2001 - 03:32 PM

#1

I just changed the cam timing to YZ spec last night. Went for a quick ride and the throttle response is still very "WR like" in low to mid rpm's. I suspect the stock DRR needle is the culprit. I ordered the YZ EJP needle and vortex ignition today. I'm going to use a 168 M.J. since the stock M.A.J. is a 200. I'm not sure if I should use a 45 P.J. since the stock P.A.J. is a 75, or should I use a 48 P.J. and switch to a 100 P.A.J. Would appreciate it if anyone knows which combination is better with the EJP needle.

  • Taffy

Posted March 07, 2001 - 01:07 AM

#2

wooow!

woooooow!

wooooooooowwwww!

slow down for chrissakes! your figures & facts are all over the show.

now then. it has always been recommended that a 100PAJ goes with a 48 PJ & that's what you can get. for an extra few dollars you should order a pilot air (jet) screw & spring which sudco do for $12. you adjust the screw to one turn which = No 100 OK?

you can turn the PA(J)S 1 1/2 turns & it will be even better (No 125). but i'm the only person running this at the moment. when JD gets his & confirms it; you'll already have the screw!

your bike should then accelerate through 1/4 throttle nicely. your MJ can stay at 168 until you've done a PLUG CHOP.

leave your MAJ (No 200)as is until JD, aussie andy & i have some figures for you. & they are imminent.

you may try lifting the needle one.

you may find turning the PS out 1/2 a turn helps. try these things first.

Taffy

[This message has been edited by Taffy (edited 03-07-2001).]

  • Jason_Foslien

Posted March 07, 2001 - 07:05 AM

#3

Originally posted by Taffy:
wooow!

woooooow!

wooooooooowwwww!

slow down for chrissakes! your figures & facts are all over the show.

now then. it has always been recommended that a 100PAJ goes with a 48 PJ & that's what you can get. for an extra few dollars you should order a pilot air (jet) screw & spring which sudco do for $12. you adjust the screw to one turn which = No 100 OK?

you can turn the PA(J)S 1 1/2 turns & it will be even better (No 125). but i'm the only person running this at the moment. when JD gets his & confirms it; you'll already have the screw!

your bike should then accelerate through 1/4 throttle nicely. your MJ can stay at 168 until you've done a PLUG CHOP.

leave your MAJ (No 200)as is until JD, aussie andy & i have some figures for you. & they are imminent.

you may try lifting the needle one.

you may find turning the PS out 1/2 a turn helps. try these things first.

Taffy

[This message has been edited by Taffy (edited 03-07-2001).]


Thanks Taffy,

I'll order the pilot air jet screw and spring. Should I stick with the stock DRR needle or go with the YZ EJP needle? I was basically trying to set my carb up like a YZ and use that as my baseline to start tuning.

  • Taffy

Posted March 07, 2001 - 11:56 AM

#4

the 'D' series is a smoother needle & the 'E' really let's rip. to be really honest you would let the stop watch decide. for what it costs try both.

i'm trying to make the 'D' stronger & to tame the 'E'. don't start confusing your MJ with your MAJ.

i get lucky sometimes when i change two things at once. recently i've been making a change at tickover & one for WOT. luckily they are so far apart that i get two seperate results.

it really won't hurt you to just play with the needle up or down one. pilot screw in & out a half turn etc. yes i know "why work when the answers there". but you need to identify rich from lean, needle from main jet etc. it'll serve you well in the long term.

i hope this is some sort of help.

Taffy

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  • James_Dean

Posted March 07, 2001 - 03:44 PM

#5

Jason,

Anything you read on the postings about EKN and EKP needles will apply to the EJP also. They are extremely close in size (EJP is 1/2 clip richer) and there is LOTS to read on these for setup and performance. Do a search on EKP or EKN to find them.

James

  • Jason_Foslien

Posted March 07, 2001 - 04:20 PM

#6

Thanks Taffy, I'll try some of the different combos this weekend. I'm familiar with indexing, but what the @#$% is a plug chop. By the way, my plug has soot on the first three or four threads, but the insulator and electrode are squeaky clean! No white ash, light tan, or residue of any kind. How much riding and what type should be done with a particular carb setting before the plug can be "read" to assist in tuning. Also, I've still got a moderate amount of metal in the oil filter even after the third change. There's only about 150 miles on it. How many miles before I can switch to 100% synthetic oil?

  • Jason_Foslien

Posted March 07, 2001 - 04:26 PM

#7

James,

Thanks for the info on the E** needles. Does this apply to the D** series as well? I will probably experiment with these (DVP or DVN) as Taffy suggested. Most of my riding is fire roads, fast trails, big hill climbs, etc. Usually at about 1000-3000ft.

Jason

  • James_Dean

Posted March 07, 2001 - 09:31 PM

#8

Jason,

The D-- needles are all over the map for clip position and straight diameter. Search on the specific code. There are good tips for DVP in particular. The tips will not apply the same for a DRR.

James

  • Taffy

Posted March 08, 2001 - 01:04 AM

#9

ditto james

just to mention that the DRR is very slightly leaner up to 1/8 throttle (tickover etc) & it is 1 1/2 clips richer already than a dvp in it's taper.

so if someone recommends a dvp 4th clip from the top you should lower your needle further to get it to the same position. so you would have the clip on 2 or 3 (in between would be nice)& the needle is lowered.

a plug chop is flat out in fifth. kill the engine with the throttle still wide open. look at the plug. "chop the ignition".

Taffy




 
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