250-500cc 09 300 idle speed.

Hi all,

My 09 300 is giving my the poops, with its very low idle speed. It has the stock TMXX on it with the stock jetting.
The idle screw is now 1 turn inside the lock nut, and it is a touch better, but still low, still a biatch to start, and stalls very easily.
JD do not make a jetting kit for it.
So , is it time for the PWk, or is there an easy fix?
If it is PWK time, what else do I need, i.e throttle cable, air boot??

Thanks for the advice people

Have you checked to make sure the pilot jet is clear? Something sounds odd that it's not idling, hard starting and stalling. Mine has none of those problems with stock jetting.

Gotlabs, it does idle, just very low. Stalls very easily, and is a mongrel to start.

I have had the carby pulled down about 5 times, and blown everything out with contact cleaner and air. Definantly all clear

I'm guessing no airleaks? Sounds really odd, mine had a very low idle when I got it but a slight adjustment and it's been fine.

Maybe you are too rich on fuel? What temp and elevation are you at, and what pilotjet, needle and needleposition do you have?

Johnny

Sounds like a clogged pilot jet. Take out the pilot and try to look through the hole while holding it up to a light. If you can't see a clearly defined hole, it's probably clogged. Contact cleaner and air will not always clean out a clogged jet. I have a set of jewelers drill bits that I use to pass through the holes to clean them out. You can also use small gauge wire. Air and solvent is not enough if the contamination clings to the passages.

Gotlabs, definantly no air leaks

Johnny, I'm running a #420 main, #40 pilot, #80 Start jet. Not sure on the needle specs, just whatever was in it. The clip was in 2nd from the top. went to the middle, and also tried at 2nd from the bottom.
Running 50:1 at about 1500 Feet. The bloody thing runs brilliantly, just crap idle and stalls

Krieg, I will pull the carb of again today and have another look and let you now what I find. But should it be clogged from new, as I brought the bike brand new?????. Cheers

Carby pulled of and dissassembled.

Needle is 6GAY69-74. No idea what that means. #4 slide. All jets are definantly clear
Everything is straight, clean and fitted correctly
Carby refitted. Still crap

Sorry to hear that. What about your air screw? How many turns out is the air screw?

Krieg, the air screw is 2 turns out.
I must admit it did seem to start a bit easier. It is a about 9 Deg C outside at the moment, it it started after about 7 - 8 kicks.
But I wont be able to check if it is better till I can go for another ride, hopefully in another couple of weeks.

Anything else I should look for?
Does my jetting seem alright?

Thanks for the help people. Much appreciated

Ok, please guy's if the bike sit's long enough for the fuel to evaporate, the bowl in the carb will be full of oil, this will cause problems on start up,
I am runing a JD jettining in my 2008 WR250 With 2010 WR300 Carb ?, and it works well. Ask for the JD kit for the 2008 WR300 and you will be be happy

My 2008 Wr250 is pulling harder then the 2010 WR300 2010, totally stock standard engine, pipe and jetting only

Might you have went the wrong way with the needle clip position? Seems like every thing I have read (Dirt Rider / Dirt Bike)
to maximize the stock carb potential, they ran the clip all the way to the top position (lean). I have been doing this with
BP 93 Octane premium fuel, Motorex 2T, Pro Circuit pipe silencer and have had zero fouled plugs. The bike rips too.....

Pretty sure my pilot is #35, not sure about the rest

cant you adjust the throttle cable at the throttle to increase idle?

RockDancer, Would that actually work, and would I not have any freeplay??
Seems like a band aid fix, I just want to now what is going on with the thing!

Mr45L, i thought the 08 250 had the older style carb??? I recieved an email from JDJetting, saying they did not support the newer TMXX on the 09's and 10??

Valhalla, I have tried all 5 spots on the needle, and it seems easiest to start 2nd from the bottom.

My jetting skills a less than knowledgeable, (Crap actually!) so I'm not sure if it's eeven close, although it does run very well, but it does smoke an awful lot. I have tried 2 different oils, and it seems pretty constant. Is smoking an indication of anything?? There is no spooge

Are you sure 09's ,10s have TMXX? - I thought that was 125/144 carb 09 up . Someone ....

I'm pretty sure.

JDJetting don't do anything for the "new style" Mikuni, so I assume , from my research that is the TMXX??

Starting to piss me off actually!

got same main & needle not sure bout others, mines 2nd clip from top of needle. It takes about 3 kicks when cold starts nearly first kick when hot. Im in SE QLD. 50 to 1 with 98 octane
Has it done many hours? The more hrs mine done the better it got to start.
its a 2010 if that makes any diff

You mentioned the idle adjuster screw is one turn inside the locknut. Have you tried going further in (maybe by 1/4 turn) and see if theres an effect on idle speed? Have you checked your float level?

I wouldnt assume too much . The TMXX looks very different and are shorter . The WR300 carbs all look like the older TMX from my 08 125 . PM Walt he'd confirm this.

I wouldnt worry about that though - whered you get the bike from take it to the dealer and let them sort it out .
It should work as it was
Dont do radical changes to neeedle heights.
If you pull the carb off put the throttle cable on and see how much slide gap there is at the back with throttle closed. Post a pic . Need to adjust slide up .

(When I put a PWk on my125 I had too much idle and adjusting the throttle cable fixed that issue for me )

also try leaner settings - the older TMX carbs have leaner settings preferred.
390 main, 30 pilot or smaller works well