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

Your new bike hasn't changed since 2011. As for the nozzle I can't help you other than I know the JD jetting kit comes with a different size so you might be onto something for helping others. I gave up on the Mikuni after I bought a Lectron. It has no jets to mess with.

The stock needle jet (I am assuming that is what you are referring to) is small on the 11 and newer wr's. The JD kit comes with a bigger one that works with some needles he already makes. I also went with a leaner slide.

Any rules for temporary rejetting after a new piston?
125 is giving rich signals low revs (sputtering on opening of throttle) and lean on top end (intermittent bog on and off revs) - this is normal?
Run in to about 300 miles now.

I would say not normal at all, If it ran ok before it should require no new jetting at all unless the bike was seriously worn out and jetted to suit the low compression.
Did you make sure the power valve linkage went back in the same place as it was before stripping it ??

Could it be more than just the jetting - float level, for example?

Yes could well be the float level or sticky float needle but before you go getting carried away try replacing the spark plug or at least make sure its not gapped to big, Chased what seemed bad jetting on my mate Trigs 125 just to find it was a large plug gap causing the symptoms (2009 model)
I personaly really do not like the Mikuni and swapped mine and Trigs to the PWK with much better results before swapping to the Lectrons with even better results

Thanks Johnnyboy!
Seriously, fitting a new sparkler is one of my favourite quick fixes too, always carry a spare.
I tried winding in the pilot mixture adjust a lil', has helped, thinking as the new piston is a tighter spec than previous could be not run in yet, in which case being too rich will've hopefully been helpful in the long run.

after 300 miles your run in should be done on a 125, if your motor is producing higher compression this usually indicates higher vacuum which in turn would make your jetting rich, i have found that the tmx carbs like a small pilot, but i would swap it for a lectron as the higher milage and better performance make it well worth the outlay.pwk are a great carb too and seem easier to jet.

Hi all, I know I should be reading this post first, I will do but I also want to ask you guys directly...

I've just bought an WR300 from 2010 second hand and it came with this carburator settings:

TMX 38 70 W8X1

-----------------

MJ:430

PJ:40

Choke:80

Slide:4.0

Needle:6BFY43-74 2nd from UP

Idle:1,75 turns

As per the official manual this is the stock setting for the WR250, is it OK to use the 300 with that or should I buy the homosexual needle indeed ?
What is the difference between this needle and the GAY one ?


Thanks .

I don't know about that needle but the "gay" needle is very lean at mid throttle. Run in at least #4. I ran at #5

Need some help guys...
2001 WR 125
Stock carb
35 Pilot
410 Main
Mix 40-1
Ride Low elevation 100-1500 feet

Bikes runs great on low end, cracks/breaks up once power band kicks in, and dies bogs down in 6th gear when flying down sand roads.

First thoughts are to lower Pilot to a 30 in the morning and also maybe knock down the main to a 390 I just don't want to go to lean with it

is anyone has same bike please let me know your setup

Watch video tell me what you think

View: https://www.youtube.com/watch?v=tk_Vic4S700

I think this video is private.
When the bikes running say in 3rd an your going 35-45 ish when you crack the throttle open suddenly does she go wahhhhhhh
Or bububbuhhhwaaaarh ? Also does she surge at constant throttle speeds if so your main jets rich.
Also have you consulted the sweet jetting database in the two smoke section? I had mikuni tm38 wich i dropped 6 main sizes on and 4 pilots was still running rich, seems itallians like smogging themselvs on incorrectly jetted bikes then treat us with the same pleasure.

If it runs great on the bottom end and idles fine, I don't think you'd want to change the pilot.

You'll need to say what needle you have and which clip it's on, that's a big part of getting a bike to run right (maybe the biggest).

Its definitely a wahhhh sound with some crackling thrown in. I will lean her up on the main and take a quick ride down the street to see what happens,.

Does the idle hang if you chop the throttle? Sounds like its lean but dont quote me on that ive got a lectron.

If idles nice goes like stink up to 6th wide throttle open how long before it dies?
And does it keep going after you roll off the throttle?

If my memory serves me right, Mikuni triple taper needles have the three letters which indicate the three different tapers; A is the least taper.

So, the GAY has a medium taper to start, very little in the middle, and a lot at the end. Your BFY is a bit leaner on the bottom and a decent bit richer in the mid. Should be better than the GAY. The DEY is another good option.

ok so put in a 30 pilot and 390 main, also played with the power valve to make sure it was working properly and moved the bolt position to high to give more bottom end power.

Results are it definitely runs better but still not what it should be. Idles perfect and good power down low, but as the power band starts to surge it breaks up and then once it really pushes though the midrange it will start to really hit power band and clean up. But still having a problem in 6th. I can blow through the first 5 gears on the power band but as soon as 6th hit it falls on it face and bogs down, almost like its not getting any fuel or its getting way to much fuel. I am going to crank it up to 6th gear run it hard and then hit kill switch kill motor and check the plug to see if its wet, hopefully that can answer my question on if its lean or rich.

PS can anyone view the above video to see what im talking about?

this video I think best shows the problem in the first 40 seconds you can see as I go up the hill on the power band the motor sounds like a raped ape and sounds like its being starved for either fuel or air


View: https://www.youtube.com/watch?v=pyLS7dPzJh0

it might sound crazy but, i chased my tail with something similar... ended up being my plug gap! my bike sounded just like yours when it hit the upper revs.

Right now im probably going to sound like a moron, are your exhaust orings in good shape? If in any doubt swap them weird stuff happens if there is letby in the header area.

Have you used the same octane gas as always?

And have you any more desert riding videos? I likey