Get the Boyesen QuickShot Accelerator Pump. It is overpriced for what it is, but trust me, it is well worth it. I have the White Bros E2 exhaust, JD Jetting, modded intake and the Boyesen pump. I have zero hesitation off idle. It really made a difference for the slow plodding tight trail stuff. I was used to an XR600 and was getting really sick of stalling out when going slow . That little battery is only good for a few starts when you aren't revving the engine. It still won't blip-blip-blip like a 600 but I don't stall out like I used to when the engine speed is near idle in the tight stuff. It is the best 90 dollar piece of metal you can buy for your 4-stroke.