Sendler had posted about this in the CBR500 thread, but I figured it would be useful to have it in this thread for obvious reasons. I'm thinking kit + fuel controller + exhaust + dyno tuning = a lot of money to spend on a $4k 250cc bike. The question is would it be worth it? Anyone have thoughts?
my whole reason for buying mine was the great gas mileage,
i think mine looks faster than it could ever go
In my youth the reason for a big bore kit was to flaunt the learner laws. Yes officer it is a 50. look it says so on the sticker. Nowadays the size is stamped on the liner casting.
There is other ways to make power than a big bore.
Yup, and cheaper. As a commuter, I can't get over 75mph without looking around for police lights, so I went with lower gearing instead. Guess what speed peak power hits at now. It starts with "seventy" and rhymes with... "seventy-five miles per hour". The rear wheel torque is night and day difference over stock. Immediate pull in all 6 gears at any speed. No pussin' around. For a BBK, I'd think you need not only the kit, but a big valve header, high-flow pipe, fuel controller, and a custom map from a dyno, You could spend over 25% of the cost of the bike modding it when there are used 600 supersports out there that would still mop the floor with a maxed out 250... stock.
... For a BBK, I'd think you need not only the kit, but a big valve header, high-flow pipe, fuel controller, and a custom map from a dyno...
To maximize the effect of a big bore kit, I wonder if a larger throttle body would be desirable. Maybe the 305 cc displacement is within the stock throttle body air flow capability to feed the motor? Back in the day, many big bore kits included a larger carb, to flow more air/fuel mixture.
Perhaps. And I'm not the most educated guy in the world on the matter, but I'm under the impression the displacement increase will add power on the bottom end, but will need to breathe better to get equal gains up top because of it. I like the idea of having the BBK option in theory, but am skeptical it may become a slippery slope and money pit.
I knew guys who would throw huge amounts of money into two stroke snowmobile engines, just to gain a few horse power from a motor already pushing 100 hp. Guess they had mad money.
