jetting for new 300 racing 2010

[fabulous furry]

i just received a new 300 racing 2010 which is actually a 2009 model out of the box but unfortunately came with the street legal gizmos that i removed but found out that the carburation feels limited my 250 EC has twice the power !.can anybody help me with the main jet and idle jet for sea level hot climate ?

 

[bondo]

I've got a 2008 DE 300 (same as EC, but no lights and smaller flywheel).

The jetting is #178 main. #45 pilot. LTR needle, clip in center position (call Les at LTR). Air screw , 2 - 2 1/2 turns out.

We run Bel-Ray MC-1 @ 50:1 with pump gas. (The Bel-Ray is a little dirty at the exhaust outlet, but does great at keeping the top end and main bearings in good shape).

Our bike starts easily, runs clean and crisp from bottom to top and doesn't foul plugs. It pulls strong throughout and runs away from our KTM 400.

 

[fabulous furry]

jetting

thanks for that but i had to reduce the main jet to 172 and it is still fooling plugs.the idle jet is 42. I use 1 % maxima castor 927 so can't go any lower in mix.

 

[stevethebrit]

Sure you got rid of all the street legal stuff?

 

[Nick]

If it came street legal it could possibly have pipe with catalyst inside, although racing shouldnt have it but possible nonetheless.

 

[fabulous furry]

the pipe mounted on is silver like an fmf the other one that came in the box is black with a tube sticking out.

 

[bondo]

With a 172 main & 42 pilot, I'm surprised it's still rich. Stock needle? What clip position?

You said you're running your oil @ 1% ? That's a ratio of 100 : 1, correct?

Bear in mind that a mix ratio of 100:1 results in more fuel in the combustion chamber as compared to a mixture of 50:1
(Richer v. Leaner has to do more with the volume of fuel than the volume of oil in the fuel).
Running a higher ratio of oil in your fuel will actually result in a leaner fuel mix to the engine.

Could there be a noise (and air) reducing cover on the air inlet?

The '08 DE I referred to in my earlier post has an FMF Gnarly and TC II S/A.

How many hours on the bike so far?

 

[fabulous furry]

jetting a new 300 racing

about the needle the carburetor is full of philips head and can't open any of the screws .i found in a small plastic bag a needle gold color CHN written on it.is it the "Nambotin" racing set up ?
i will try 2% as recommended then and set everything back to main 178 and idle jet 42.
the air filter reducer is removed.
the bike will go on the third tank.

 

[bondo]

No idea about the needle. After three tanks, the engine should be
sufficiently broken in. Hopefully, the 2% oil mix will do the trick for you.
Did we discuss the air screw? A small detail, but will influence off - idle response. (I usually find 2 - 2 1/2 turns out is a good place to start).

If you're still unsatisfied, try speaking with Mark at GoFasters or Les at LTR.
They're both very knowledgeable. Links on this site.

 

[fabulous furry]

that was a great help. i went back to the original setting as it came 175 main and change the plug for an iridium ngk it is cleaner.gas mixed at 2% with maxima Bio 2t.
august in the caribbean is 100% humid and temp is around 33 C so it does mess up the jetting but never had any problem with the 250 .