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EDDIE, please help with wr athena 290 bog leak needle TPS o-ring mod jetting

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Title is set up for others to search from since I had troubles searching for athena 290 specs but my questions are mainly bog related and one word answers will be sufficient. Bike is an 05 wr 250 with the athena 290 kit, opened up, yz pipe and exhaust cam. I have only made one attempt at jetting since the bike only has 20 minutes on it. Elevation is 300 ft. and temperature will be mainly in the 80's and humid.

1. Should I unhook the TPS for only jetting or all the time?

2. Which leak jet should I use with the o-ring mod on the AP?

3. Is changing to the yz PAJ needed after disabeling the air cut valve?

4. If you had to choose one Yamaha needle, which one would it be? (I have the needle that came with the AIS kit)

Thanks!

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1) only if you experience a stedy throttle miss that isnt affected by jetting.

2) there no set answer to this.eveyr bike seems to be different.around a 60.

3) in the open or closed position?

4) ELP

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If the air cut valve is disabeled then it would be like the yzf which is closed off. The yzf uses a different PAJ in the back of the carb. Do I need that jet or can I just offset it by tuning the pilot jet and fuel screw?

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I've read that you should go to the YZF PAJ whenever you intall the YZF exhaust cam. That's what I did with mine, and it worked out fine.

I don't have the 290 kit though (which makes me jealous), so YMMV.

Eddie, one word answers may be sufficent for Wideopen, but I'd like to know more about the effect of the ACV mod on the PAJ selection. Could I get you to provide a little detail?

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depends on how its disabled.

basically under heavy decel,the valve cuts off the the auxillary air jet to make the mixture rich.this is done to calm decel pop with epa jetting.

if you disable it so it cant "cut the air" on decel and it uses the aux air jet and the pilot air jet still then there is no reason to change the pilot air jet.

if you disable it so it can not use the aux air jet then the size of the pilot air jet needs to be changed accordingly.

100 pilot air jet is usually the choice.

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