need some help - Athena 290 and jetting

Ok, I know jetting and the Athena issue has been hashed a thousand times. Well, I searched and didn't find all of my answers, so here I go.

First off, I just finished the install late last night.

Today, I go to start it and it takes a bunch of kicks, but does start. It seems to run fine with the choke on, I let it warm up for a little bit and turn the choke off. Idle drops a little, then dies. I go through this about 6 times and then figure I better clean the carb. I drop the bowl and clean all 4 of the jets, main, pilot, starter, and leak. Put it all back together and I get very similar results. It seems to want to idle now, but as soon as I blip the throttle, it dies.

Current jetting is totally stock:

main 182

pilot 42

starter 72

leak 90

fuel screw is current at 1.5 - the idle does change when I switch the fuel screw. Turn it in, idle slows down - out, idle goes up.

Ok, so now I search here and then I read people talking about the Athena kit having 5 rings and 3 slots on the piston. Mine only had 4 rings and 2 slots. This has me a little worried.

Can anyone point me in the right direction with jetting or at least ease my mind.

thanks in advance.

I can only tell you how far I got. I use a 158 Main with an EHP-3 needle @ 4600ft. If you work this back you might want to start at a 170 main. I tried a 40 leakjet but that didn't work, a 60 worked great. Anything more than this you need the assistance of the BIG GUNS...

How did it run before you installed the 290 kit? Were you having any responce issues?

If it was fine before, you may want to check your installation. An air leak or a cam that is not timed properly could cause some of these problems.

Usually jetting will need some minor adjustment with a big bore kit, but the kind of problems your describing are unusual.

Nevermind, The exhaust cam was 1 tooth off. It runs a whole lot better now. Just like it did before the kit.

I thought it was just like when I took it apart, but obviously not. It is amazing what 1 little tooth does.

Thanks. Now to figure out the jetting to get better throttle response.

So how's the power? Do you notice any negatives?

So how's the power? Do you notice any negatives?

Ok, I put 1.5 hours on the 290 kit yesterday. Here is what I noticed.

First, I need to rejet and fix my throttle response. Powerwise, WAY more low end and mid range, but signs off quite a bit more than I would like, but I think I can fix that with gearing. The track I rode on yesterday is 100% sand, so that probably attributed some to what seemed to be a huge lack of top end.

Overall, I think I will love this motor once I get it jetted. Definitely hits HARD on the bottom, but the top is weak. This would be the ultimate Arenacross/Supercross motor.

Does anyone know where I can get some leak jets?

Does anyone know where I can get some leak jets?

JD Jetting

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