I'm new to this so please bear with what might seem like a dumb queston. I see a lot of post on forums talking about uncorking a DS bike with a carb. My queston is, if you uncorked a2008 - 2012 xt250 would it be perform better then a 2013 xt with Fuel injection? My gues is Fi would be better but again I'm a newbie.
"Uncorking" a bike is about removing intake and exhaust restrictions. Both of which the EFI bike will have. Once the bike can move some air you have to recalibrate the mixture. With a carb you rejet richer. With EFI you need to recalibrate the ECM or add a piggyback controller unless it has a downstream sensor and can adapt. Which is doubtful on something like an XT250. The properly calibrated EFI on an uncorked 250 will probably get better mileage and perhaps a small performance boost over the same bike with the same mods and a rejetted carb. But doing anything to the mixture without removing air restrictions first won't do a lot for performance on either. Changing the mixture with EFI is easy enough as long as somebody has the tuning equipment or makes a controller but more expensive than a jet kit. That caveat above is important. Because if you open up the airbox and exhaust and can't retune the EFI or the EFI can't compensate then you are going to be running the bike way too lean. Too lean means too hot especially with an air cooled XT250 which is already running very lean from the factory with the stock airbox and exhaust. Every dual sport I have ever owned from my ancient XT200 through my LC4E has been "uncorked" and rejetted. So I can do the carb ones. Somebody else will have to help you out for recalibrating EFI. I am not quite ready to make that leap unless it is for a bike I know already has aftermarket tuning capabilities. I have no clue about the XT250. But I can tell you adding a Supertrapp, higher compression piston, cutting open the airbox and rejetting my ancient XT200 turned it into a little screamer. Same for my XT350. The 350 demanded it it even stock because Yamaha jetted them stupid lean with that ridiculous YDIS carb.
Avoid FI like the plague. FI is a complex system with lots of components that can and will fail. It is in new bikes to pass emission standards, at the expense of reliability and simplicity.
Hey , they recently discovered the world is not flat. The only simplicity here is your thinking. Ive had fuel injected bikes for the last 15 years and some bikes had it 30 years ago. Ive never known anyone whos had problems and Im sure you only heard something from somebody else. Hell , Ive only ever had minor problems on cars. Its not black magic , you dont have to be afraid because you dont understand it. As far as tuning , its easier / quicker to do. If you cant tune FI , you shouldnt try it with your carb either.
To me "uncorking" is only when something is "corked". Restricted intake manifold on the XR650R or a throttle stop on a WR450. There are very few bikes that are restricted from the factory and those are the only bikes that need "uncorking". Doing what some consider as "uncorking" is just a waste of money and fuel. IMHO of course. YMMV
Thanks for the help, but I should clarify. I don't want to uncork the Fi model I was just wondering if a stock Fi xt250 would out perform an uncorked xt250 both being new bikes. I'm trying to way weather it's worth the mony to get a 2013 over a slightly used one. Sorry I should have been more clear.
I would say the comparison would depend on weather conditions and altitude , bacause the FI can adjust itself.
Totally. Also stay away from them new fangled brake systems with rotors and calipers, drum systems are simple and never fail. Don't even get me started on cast wheels....
You still need to uncork most FI bikes, especially street legal ones. A tuner is usually easier to plug in the re-jet though. Injectors are more expensive than a jet and harder to clean. Gravity is a lot cheaper than a fuel pump too. FI manages fuel better in a variety of conditions, works great on a street bike and it's getting better on dirt bikes. I have both but at the moment my injected bikes are street bikes, although I have ridden a bunch of FI dirt bikes. Throttle response is great but I also work on these things a bit so I also have had to swap a few injectors.
