All 2st Jetting Chat - Need Help? Post Your Questions Here

[MattR]

Just a suggestion...

Can one of the moderators sticky this thread?

 

[tony_dt]

Can one of the moderators sticky this thread?

Please, it would be nice not having to search for it and this is a thread everyone needs to see.

 

[Johnnymannen]

Hi, All
I will give the spec's my bike runs in Sydney Australia

Year & Bike Model = 2008 WR 250
Carb = TMX38
Pipe & Silencer = DEP PIPE & FMF TURBINE CORE 2
Other engine mods = 0
Premix ratio & fuel type = 98OCT 50:1 MOTUL 800
Temperature range (deg C) = 18-20
Elevation (meters) = 250
Main jet = JD 390
Pilot jet = JD 30
Needle = JD RED
Clip position = 3RD
Air screw setting = 2 1/4
Slide = 3
Air filter: Twin Air

Conclusions/Results = my bike was real bad to ride. The float level was 2mm too high. This was a constant cause of fouling plugs. I would foul 2-3 plugs every ride, this would happen riding in the lower rev range on tight tracks. On down hill descent, I would get to the bottom twisting the throttle only to foul another plug. The high float level was the cause of flooding, burning off the fuel, but not all the oil. I also had the same problems riding on flat ground in the lower rev range. Heavy braking would also fuel the engine up and foul another plug. On cold start up my bike would moan and cough. I was at the point of no return, this constant headache had to go.

The above specs are a recipe that has now produced a nice clean crisp bike. On cold start up, I do not require the choke. The engine spins up very quick with no moan, and no longer fouls plugs. The bike now rides like a dream, pulls hard off the bottom right through to the top end

With that jetting and pipe combo, my bike produced on the dyno
42rwhp, 26ft/lb torque @ 8500rpm.

A big thank you to Steve Cutting
@ Motorcycle Weaponry 7/8 Wilmette Pl
Mona Vale
NSW
Australia
Ph: 029979 4744
Fax: 029979 4745
Motorcycle Weaponry is also on the Net[/U][/U]

Ok, intresting! Did you try any other jettings in the dyno? Have you tried a bigger mainjet?

Johnny

 

[ohmygewd]

^bump^

Mods...could you please sticky this???

 

[rockdancer]

Check plug
Make sure the plastic slide spring retainer is in the slot correctly
Try using the 175 main if you got one with the carby
or if you think its rich try lowering the needle one setting
if this works
it may also make it lean down low so 165 main maybe the way to go

 

[ohmygewd]

Hey Leepat

Keihin slides effects closed throttle to 1/4 throttle (see keihin slide chart below)
http://keihincarbs.com/images/valvolegas-chart.jpg
http://www.keihin-us.com/am/_media/pdf/carbslides.pdf
Keihin tuning guide
http://www.keihin-us.com/am/_media/pdf/slide_valve.pdf

5.5 at the 'middle' end of the scale.

I run a #7.

 

[Leepet]

Awesome! Thanks mate. I haven't seen that chart before but it explains why I need a needle with a larger diametre than most.

 

[HxcEnduRo]

anyone can help me with a suggestion for a eg 144 at sea level central coast california

 

[ohmygewd]

use this database mate!!!

 

[marcmo0]

So I just received my PWK with JD kit. It came with the blue needle installed in clip #2. I ride at altitide. No lower than 4000ft and up to 12000 in Summer. Isn't the JD red needle for altitude? 170main 45 pilot

 

[marcmo0]

I just installed the PWK, what throttle cable are you guys using? Was it a '99 Honda CR 250 cable? I think I remember reading that somewhere, but couldn't find it on a search. My stock cable has too much slack to adjust.
Thanks!

 

[Johnnymannen]

I use my standard cable. Works perfect. Just changed the end pipe and nut and use the bent one. Check that your airbox doesn´t rub a gainst the rear spring as the carb is slightly longer and pushes the airbox backwards a bit. Get back about your jetting!

Johnny

 

[Johnnymannen]

So I just received my PWK with JD kit. It came with the blue needle installed in clip #2. I ride at altitide. No lower than 4000ft and up to 12000 in Summer. Isn't the JD red needle for altitude? 170main 45 pilot

What temps do you have? I personally prefer the red needle as it´s smoother/leaner from the bottom, but it depends on how and where you ride of course!

 

[ohmygewd]

Took my WR360 and a mates with a the old Dellorto....chalk and cheese and painful memories of what the 360 (his fouled just on warm up) was like when the jetting was screwed before the carb swap and jetting sorted
Temp: 28C
Elevation:650mt
Ride type: hill climbing with fast single tracks.
Conclusion:
Bike needs new rings as the comp is low compared to a fresh, completely rebuilt 360 (jealous).
I might try a JD Red needle and feel the difference, possibly drop the clip to the middle to smoothen the transition from 1/2 to WOT.

 

[marcmo0]

I use my standard cable. Works perfect. Just changed the end pipe and nut and use the bent one. Check that your airbox doesn´t rub a gainst the rear spring as the carb is slightly longer and pushes the airbox backwards a bit. Get back about your jetting!

Johnny

Thanks dude**************************************** Just made the swap, and the cable is, as you said...perfect. NOW, if I could just get the snow to go away....

 

[Johnnymannen]

I just came home frpom an evening at the ice! We had a fantastic evening race on the ice today! Totally black in the woods, and just screaming bikes with their headlight on sweeping over the frozen lake! I tried the red JD needle in myWR 300 today to compare it to the EEL i had last time. It was worse. The red needle is to mellow from the bottom for iceracing. The EEL comes on much better exiting corners! Therefore i will change back again. It also felt slightly too rich in the middle (bluddering on medium throttle). I had both needles in the middle clip pos. 182 main at about zero degrees.

Johnny

 

[Johnnymannen]

Year & Bike Model = 2009 WR300
Carb = Keihin PWK 38mm A/S
Spark Plug = BR8ES
Pipe & Silencer = Pro Circuit Plat. 2 and 296 silencer
Other Engine Mods = none
Premix & Fuel = 32:1 (Klotz R50) with 91 octane

Temperature range (deg F) = 30 to 40 degF
Elevation (feet) = 500 - 2000 feet
Main jet = 178
Pilot jet = 50
Needle = CEK
Clip position = #1
Air screw setting = 1.5 to 2 turns out
Slide = stock from PWK for 99' CR250R
PV Spring Combination = OEM
Conclusions/Results = this combination worked great at my house (300' ASL and temps nearing 50), but the lean needle position failed miserably at the forest with cold temps and varying elevation. The 50pj and 178mj were what the motor needed, but I had terrible fuel starvation on the needle.

I have never been real happy with how the bike transitioned into the midrange and always thought it was a too rich condition on the needle, but now I'm thinking its a lean condition. I'm going to try this same combo, but with the needle in the #3 clip next time and see if midrange improves.

The 178 main pulled like a madman on top. I had forgotten how fast this motor was!

Hi PC! Have you tried the EEL needle? Ithink you would like it! Get one and try it in 2nd clip is my advice! I use it on the icetracks now, and i tried it in 3rd last week, but at around zero Celsius i think it´s really good in 2nd. More taper(richer) then the CEK and slightly leaner on idle=)!

Johnny

 

[PC.]

I have not tried it Johnny, but I will buy one first chance I get. Isn't the EEL needle very close in spec to the JD red needle?

 

[TROFFER88]

jd red is very close to ceq

 

[Johnnymannen]

I have not tried it Johnny, but I will buy one first chance I get. Isn't the EEL needle very close in spec to the JD red needle?

The needles has about the same base diameter(lean), but as the red JD is tapered differently to the straight tapered EEL it makes it quite different. The red JD is softer/smoother from the bottom and makes the bike more controllable at light throttle.The EEL has more hit right off throttle. Conclusion1: EEL has a more linear powercurve. Stronger off throttle, less hit in the middle and revs out about the same as the redJD.
Observe that this is MY conclusion=)! But i have tried a lot

Johnny.