[Hondarider1243724]

I have a 2003 Honda 300ex and I recently put a 400 ex carb in it, I have it spotters out whenever I’m doing wheelies or going up hills, I have a Uni air filter lid off of the airbox, and I have a big gun Evo slip on exhaust, it’s still sputtering out and losing a lot of power. Please help.

 

[oldskool83]

its prob jetting too fat. you should be around 42 pilot and 160-170 main depending mods. Go down 10 on your main, ride it. A good trick is use a hill and mash it or pull a horseshoe. It it falls on it face its too fat. plug chops are pointless with todays fuel. Corn 93 burns way hotter then ethonal free 90. Depending on your compressinon ratio you might want to look at fuel also. I'd never run anything less then ethonal free 90 on a 10:1 motor, 11:1 corn 93 is ok.

 

[Hondarider1243724]

okay thank you for your help how would I turn the main jet down

 

[oldskool83]

you do no turn a main jet down hoss...you replace them. I have hundreses of sizes here. you;d need to buy a range and try. plastics, come off, gas tank comes off carb comes off and remove it. bowl comes off and main jet comes out. 1st buy a manual. Lets go from there so you can see what you have to do.

 

[Hondarider1243724]

I got it, I ain’t stupid. Thanks for treating me like a Idiot

 

[oldskool83]

If you don't use the correct terminology then yes an idiot comes to mind.

 

[Hondarider1243724]

All because of a main jet in a carb 💀

 

[oldskool83]

yep. its jetted too fat. Pull it look at the size. Tell me the number I'll send you a range to fix it up. Stocks a 38 pilot and 128 main....My 300ex runs a 42 pilot and 168 main...but its an ex national level motor i detuned. Your plug should be black as coal.