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Michigan U.P. 3x3 Acceleration Lag


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Hey Everyone. I've spent some time looking through a lot of posts looking for an answere to my dilema.

Did the 3x3 with the DJ kit.

140 main, 4th clip on needle

25 pilot

Extended air screw

700-800 Ft elev.

Loved the mid rang pull after the Mod! But now have a hesitation when cracking the throttle from the bottom.

Tried leaning out by raising needle 1 clip seemed a bit better so i tried going up another clip. Now I have lost all that power I gained. When I raised the needle the second time I had to open up the air screw 1.5-2 turns. I can still feel a slight hesitation and have lost all that power.

I think I need to go back to the fourth clip and lean out the pilot jet, but I'm not sure. Just after I did the mod I could turn the air screw all the way in and the engine would not stall. I could turn the air screw out to 3 turns without any pronounced difference in Idle, although it was smoother. This makes me think the pilot is to rich.

:banghead:Any input would be appreciated, thanks.

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go back to your original settings (after the mod of course) but try turning the air bypass screw in all the way and turn it out just 1/2 a turn out and go for a ride. What is happening is that you have a proper MAIN Jet (hence the good mid-range+) but the air bleed is letting too much air through at low revs, causing a lean idle condition. When you try cracking the throttle open from idle the engine doesn't have sufficient fuel for the rapid change in airflow so is hesitates until the main jet starts delivering. When you leaned out your main jet you basically matched the lean condition you have at idle, so now you have a lean condition everywhere. It takes care of the hesitation because basically now you're down on power everywhere because of the lean condition so you don't notice a "flat" spot. Go back to you're starting settings and close the idle air bypass needle. ­čśĆ

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Thanks RZ-Jacks. That makes sense. I think I am going to go to a bigger pilot jet, perhaps that will get my air bleed screw in the proper range 1.5 to 3 turns out, and give me the response I am looking for. Thanks for your reply, very appreciated.

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I used the Keintech. Tried a bigger pilot today, 27.5. Seemed to eliminate some of the bog, but the engine cut out completely on me twice at highway speeds. I had to keep the petcock in the prime position to keep fuel running to the carb. I also had to turn in the fuel screw alot to start the engine. Mabey I should go back to a 22.5 pilot. This is all trial and error.

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This is wha I got from reading too many threads

3X3 hole

155 MJ with stock exhaust, 160 with free flowing exhaust

22.5 (stock PJ) with Kientech fuel screw or 25 PJ with stock fuel screw

4th clip, blue

2.75 turns

Isn't the stock MJ a 142.5?

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This is wha I got from reading too many threads

3X3 hole

155 MJ with stock exhaust, 160 with free flowing exhaust

22.5 (stock PJ) with Kientech fuel screw or 25 PJ with stock fuel screw

4th clip, blue

2.75 turns

Isn't the stock MJ a 142.5?

I believe you are quoting the specs for the James Dean kit. The OP says he has the Dyno Jet kit which has a different needle requiring a different main jet. Yes the stock MJ is 142.5

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