Jetting with Athena big bore

[Relaxinjackson87]

Hi guys. I am resurrecting by 01 Banshee and I would like to know your opinion about where I should start as far as jetting. I have the following mods: Toomey T5s, K&N air filter, stock air box with lid removed, Athena big bore (392cc). Everything else is stock. Elevation is sea level to 500ft. Temp 60-80 degrees. I rebuilt my carburetors using 30 pilot jets, toomey needle set at 3, and 330 mains. Is this a good starting point or am I going to blow it up? Thanks for your help. 

[toytech]

nobody on here runs the athena kits. but I would say thats probably lean, start with bigger jets and work down.

[RadarRacing]

Start high always and if its overly sluggish jump down a couple and tune down till its spot on. Your 330 may be spot on but dont start there. Start 370 or higher minimum if you ask me. I would guess with your toomey needles your 330 will be close.

[trickedcarbine]

Pretty big motor for stockers. Your current set up seems pretty close. But I would start at 360/370ish. Better safe then sorry.

[Russell Wealthall]

One off my sons runs a athena

25 pilot toomeys needle 360 main on his t5

Toomeys high flow foam on stock cage( flows the same as k&n holes in airbox

Runs perfect plug colour

But tranfers are way to low no bottom end

Took 40 thou off the bottom to bring the power on sooner which it did but the transfere then measured 109 degrees to ex 188

Ridiculous raising them up to 128/130 ish

Good transfere area good inlet size good tripple port ex

Hits really hard but only cause thre ain't no bottom or low mid no matter jetting or timing

[trickedcarbine]

That pilot is WAY WAY lean for that set up! Try the 27.5 pilots, maybe even a 30 as the motor is a big bore. Put the needle on the second from the bottom clip, and maybe work your main down a size or two. Your main definitely sounds close and you said it's giving the plugs a good color, so try a size down and see what happens

Edited July 5, 2014 by trickedcarbine

[Matt3406]

@Russell Wealthall

Hey I'm no expert on timing or jetting but I'm also putting together an Athena engine and came by your post. I currently have a stock engine in my banshee and for shits and jiggles I wanted to see what retarding the timing did because I have always ridden it with +4. I set it at +2 and there was a world of difference in a bad way. Instead of the crisp transition from low and mid to top end there was a major lag on the low and mid then when it hit the power band it went nuts. With the timing only at +2 the quad has no low end and way to much top end. Ik you said your son is having this problem no matter the timing but I would suggest advancing the timing and seeing if the transition gets any better.