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

No. It's almost all the way down. I started out with it in the middle but it was rich in the lower RPM so I lowered the needle.

If it's knocking in the midrange it's either lean or your fuel isn't good enough. Try mixing some 110 50% with what you have. You could also put a 1/2 step washer under the needle to split the difference between the too lean and too rich groove. I had a similar problem with my 250 and the 1/2 step helped but still had to go to a needle that had a less drastic step in the dual taper needle.

Walt mentioned he was running the 16-61 needle, is that richer or leaner then the 62? Which needle did you go to?

Or could I go with a smaller pilot (35) and raise the needle back up?

My bike is a 250 so I went from the stock needle to the less tapered GAY needle and ended up with it in the 4th notch.(one step from full rich) I'm not sure which 125-144 needle would get you where you want to go but I bet Walt would know.

I am having the exact same problem as you with the 16chy16-62rm needle,30pilot,460 main,#5 slide airscrew 1.5 turns out.I have my needle clip in the top(leanest)position and have a "knock" when rolling on the throttle from half to full throttle. If I raise the needle to the next position it runs too rich below half throttle.I use 94 octane non-ethanol pump gas and 33:1 pre-mix. I have installed a 470 main jet and turned in the airscrew a quarter turn and I will see if it helps. If I still have problems I will put the 460 main back in and try a half-clip washer under the needle clip in the top(leanest position).As lankydoug has said before and I know this myself,the different circuits on these mikuni tmxx carbs over-lap quite a bit and making a change in one circuit can really affect another.I also have a #4 slide and the 6dey-15-74 needle, I wonder if they can be made to work better than the current set-up Good luck to both of us!.

that is why I like the 17-62 in the #3 , it is half a clip leaner than 16-62, no more ping

huskybear - I started with the 460 main and was way too lean. I'm now up to a 500. Walt recomended going to a 37.5 or 35 pilot and raising my needle 1 clip. He also said I might try mixing in some Av gas to see if I need to change the base gasket to lower the compression.

Troffer - Thanks, I'll keep that needle # in mind as another posibility.

Guys I need some help. My '11 WR150 is running like crap. Bad bog down low and is climbing hills like crap. I have a fmf fatty and PC2 silencer. Thanks, Nick

Year & Bike Model = 2006 WR250
Carb = Mikuni TMX38 (flatslide)
Pipe & Silencer =HGS pipe, stock silencer
Other engine mods = none
Premix ratio & fuel type = 50:1 and Putoline MX7 or MX9
Temperature range (deg F) = 64degrees F, 18 degrees C
Elevation (feet) = 900 ft 275m
Main jet =420
Pilot jet = 30
Needle = 6DJ8-60
Clip position = second from top
Air screw setting = 1 1/2
Slide = 3.0

Conclusions/Results = Rich in the bottom end (plug is black and wet), pulls hard from about 1/4 throttle to WOT (plug is brown)
I tried adjusting the Airscrew out (until 2 1/5), but it didn't feel much better, actually I believe it got worse (more blubbering), which is opposite what I would think in theory about turning the airscrew out (anti-clockwise), would make it leaner.

Would you recommend switching to a 27,5 PJ (I'm thinking that would be strange considering the Husqvarna template says around 35 and would be very lean), or is the slide wrong would a 4.0 help me.


Compression couldn't be the problem, piston is around 18hours old, air filter is clean.

I'm interested in a TMXX carburetor (found on >09 2t), so when anyone wants to get rid of theirs please have a chat with me. Also interested in a 4.0 slide for original TMX flatslide

With kind regards, Bart

Year & Bike Model = 2012 wr300
Carb = stock
Pipe & Silencer =Stock
Other engine mods = none
Premix ratio & fuel type = 50:1
Temperature range (deg F) = 64degrees F, 18 degrees C
Elevation (feet) = 1000 ft
Main jet =stk
Pilot jet =mstk
Needle = stk
Clip position = havent checked yet
Air screw setting =
Slide =

Started my yet to be ridden 300 for the first time in between mothers day honey do's yesterday. It took a lot of kicking and wouldnt fire until I gave it about 1/4 throttle. After warming up and running up and down the street a few times, it seemed to run okay but it will not idle so my first objective is to address that and the hard to start condition. Should I start with the jetting, needle, airscrew, throttle cable adjustment or all of the above? Would appreciate advice. Thanks

For break in they recommend 32 or 36 to 1 oil ratio. A good starting point for the idle is, air screw at 2 and put the idle adjustment screw about flush with the lock nut. Some 11's came with the wrong jetting, hopefully they sorted it out on the 12's. If you ride in fast desert areas, be careful with long runs at about 1/3 to 1/2 throttle with the stock needle position. To make mine live I moved it full rich, position 5. (3 is stock) The 11 factory hop up jetting is (on mine) 420 main, 45 pilot gay needle at #3, #4 slide.

Thanks

maybe grab a needle shim next time you're at the parts store then you can run the half position on the needle.

I had a similar problem with the stock needle on my WR250 after I installed the FMF Gnarly pipe. The solution for me was to use a needle with less taper which was the GAY needle. I'm not saying that you need the GAY needle but one with less taper would probably get you the results you need.

Thanks for the replies, I think I am very close to getting it perfect. I am riding this weekend and if the jetting is right, I will post my settings in the jetting database.

Question for all you experts: Is this amount of carbon build up a bad sign? It seems quite thick, but the bike runs great.

I'm replacing the ring now, and wondering if I should clean it or worry about my jetting at all. There is some carbon build up in the pipe and a small bit of spooge coming from the silencer.

T hanks in advance.

Yes you should clean the carbon. Some oils are worse about forming carbon and others produce more spooge. When the jetting is correct and you are using an oil that the flashpoint is low enough the oil will burn and there won't be much spooge. Leaner jetting will produce more heat and burn the mix oil but don't jet according to spooge rather jet according to performance and choose an oil that suits your riding style. There are lots of opinions on oil but generally full synthetic race oils like Ammsoil Dominator have a slightly higher flashpoint and will produce more spooge if you are jetted rich and putt around on the pilot a lot. Re-packing your silencer every 6 months or so will help performance especially if your jetting is rich and making spooge.

sorry if this has been posted already. Where is a good source to buy an assortment of main and pilot jets for a Mikuni on 2012 wr144? And does the tmx and tmxx use the same jets?
Thanks

I bought all my mains and pilots through my local yamaha dealer (it's closer than my husky dealer). Just ask for jets for a 2008-2011 yz125-it uses a tmxx. I am not sure if the tmx and the tmxx use the same jets but I am sure some-body else will chime in and help you out!.

Thanks mate...I'll check with my local dealer tomorrow