What a topic. It is still coming up 30 years later. You would think by now, you would have accurate information on how the Engineers came up with V-Boost. Its been so long for me that I may miss something. If you dig hard enough, you will find GK dynamics theory of operation. So much to convey, just not enough time to post all of it. Zues36 is the one that essentially described the "hidden" design that few actually get. Yes, two carbs will feed one cylinder. Length of the runner is tuned to RPM like any other motor. However, using the adjacent cylinder at the proper time will induce a negative intake pulse into the cylinder that acts like a "mini supercharger". GK dynamics never changed there thinking for the Gen II. It's all about accelerative fun. Period. Its the "hit" that makes you smile. There are bikes that are faster. But are they as fun?
Now, does anyone know were the 120HP club went? You'll see me there at 12 or 13 at 130.1 Uncorrected HP on a DJ150. NO stage 7. Stage 7 kit was VERY difficult to tune. I HATED DJ jets. Taking V-Boost off LOST the fun and drivability. You had a nasty hole from 3k to 6.5k then you make 3HP more peak. Was it worth it? Hell NO. My '98 spent more time on the dyno than riding it. I was hell bent on getting the tune absolutely perfect. Took a few months and hundreds of dollars of dyno time and experimentation. ALL Dyno jet kits were always a struggle to get them perfect. Period. I stopped using them with there proprietary main jets and went with Marc's at Factory Pro. Way Way better needles. Then, a friend in Canada turned me on to a very cool idea. Needles from a 1984 Venture that were adjustable. Cant buy in the US. Non US models only. Thank you Tyler P in Ontario.
OK, the year I spent playing, I was right back to V-Boost on. Y off. I even made an adjustable controller using a N555 timer. I could open early at 2k and as late as 8k. It felt quicker opening at 4k. But the dyno showed otherwise. Took controller off. Made consistent 128rwhp SAE every time I ran it.
It would WHEELIE in first gear rolling into it to hard. I rode with a friend with UFO Vgas. I'd beat him every time doing roll ons on the I20 in SC. Then he built a PCW 1500. I got whacked.
OK, another tidbit. I had multiple 2004 Kawasaki 700 V-Force ATV's. Someone came up with cross plane intakes to mimic V-Boost. Very impressive intake. I had to flash back and try them. So, I had to retune the 32mm carbs( i think) with way smaller pilots, I used ZRX1200 Factory Pro Needles from Marc. I tuned it while racing it with a wide band LM2 A/F Meter. ABSOLUTELY NO GUESSING. OMG was it a scary ATV. My friend Mike had a BRAND new CanAm 1000 sport. This was more than 10 years ago. He would pull me to about 100 ft then I would leave him for dead. He was so pissed that I beat his 10,000 dollar atv with a beat up used one that he rode off and wouldn't talk or buy me the beer he owed me. Um, it had Stage 1 Hot cams in it to...to be fair.
So what am I saying? Leave boost alone. Just make sure its clean and functioning. Call Factory Pro in Caleefornia and see if they still have the kits.
