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JD Jetting FCR and accelerator pump??


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I did the JD kit install in my Beta 525 RR bike yesterday. In the kit I changed the main jet to 172.5, the needle, and put the small O ring around the arm for the accelerator pump.

In the kit was another small piece that could be put on the center stem of the accelerator pump diaphragm. This would limit the travel of the pump.

I did not do this mod.

Wondering for those that have done the JD kit, how many pulled the accelerator pump and put this piece on, and was it noticeable after you completed.

Right now the motor sounds pretty good. The only item to get sorted out is when at idle, and moving the throttle rapidly open there is a hesitation. If the RPM's are up, or moving the throttle moderately everything is good.

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Well, I'm still waiting on a reply to my post, but you answered one of them anyway. I guess the JD kit comes with some type of extender that mounts on top of the diaphram to shorten the duration of the AC pump. Yes, I'd install it if I was you. Actually, that is the most important part IMO, along with the o-ring or heavier AC pump spring. I hate to spend a lot of money on the kit when I feel I can get the Pilot, Main and stock needle pretty much where I need it. But the KTMs do not have a bleed jet, and I timed the duration on my bike at about 5 seconds, way long. That means if you open her up, she squirts that long even if you back off the throttle. I prefer a much shorter squirt since I race offroad and a small blip of the throttle is needed to get up and over a log (getting more and more common for our tracks to have a small enduro cross section in them) or hop a ditch, creek etc. I'm trying to decide if I should buy the JD kit, of buy a Honda diaphram (center is longer, just like your extender) or just make something that does pretty much the same thing. The o-ring in your kit can shorten the duration slightly, but is more for just getting a quicker, harder burst of gas when you twist the throttle. Remove the subframe and time your squirt. If it's 3 seconds or less, and you do not race or need short bursts, then you probably don't need to install it. I'd be curious what your before duration is, and then after the install. And what the effective length the extender added. I'm tempted to just make one on my lathe. Also, almost all 4 strokes will die if you just wick the throttle open as fast as you can from idle on the stand or riding it. They are not 2-strokes, you roll the throttle.

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