One aftermarket product that is often ignored is the Electronic Fuel Injection (EFI) Controller. Simply stated, an EFI Controller like the EJK EFI Controller shown above, is highly recommended any time you install an aftermarket exhaust and/or intake/air filter on your 2008+ Yamaha WR250R (or WR250X). They can also provide benefits even if your engine is completely stock. See below for details...
Benefits on a Stock Yamaha WR250R/X:
If you plan to keep the stock exhaust system on your WR250R, installing an EJK EFI Controller is possibly the best bang-for-the-buck modification you can do. No other bolt-on aftermarket part will give you such a noticeable performance difference for the same $225. The WR250R runs lean with the factory fuel map and really falls on its face in the low to mid range when you hammer the throttle. An EJK Controller will add add a bit of fuel in the green zone (about .1 ms to the injector pulse width), a decent amount in the yellow zone (about .25 ms to the injector pulse width) and nothing at full throttle/red zone. This will improve performance in the low and mid-range power curve and still provide plenty of top end performance. You will also notice a more crisp throttle response and the bike will run cooler. Later, if you decide to add an aftermarket exhaust and/or intake, the EJK controller can be adjusted appropriately to take advantage of the new performance parts.
NOTE: Since the EJK controller comes pre-programmed for Stage 1 mods, if you're installing it on a stock Yamaha WR250R/X you will have to make a few simple adjustments. See the section labeled "Settings for stock exhaust and air box top eliminated." at this link: http://www.electronicjetkit.com/DirtBike/viewproduct.asp?partnumber=9310207
Benefits on a Stage 1 Yamaha WR250R/X:
If you've decided to add an aftermarket exhaust and/or intake system (Stage 1 mods) to your WR250R, an EJK EFI Controller is HIGHLY RECOMMENDED if you want to take full advantage of those performance parts. Aftermarket intakes/air filters give your engine more air, and exhaust systems allow it to breath better. Without an EFI Controller, the bike will run lean and you may experience pinging or backfiring, and the bike may run hot. Additionally, without the proper fueling that an EFI Controller provides, you will see little to no performance gains from your new exhaust system and, in fact, your bike may run poorly. EJK pre-programs their EFI controllers to work with Stage 1 mods (exhaust and/or intake)... they add .2 ms to the injector pulse width at green fuel zone, about .5 ms to the yellow fuel zone and again nothing at full throttle. Combining the EJK EFI Controller (or the FMF branded version) with an exhaust system like the FMF Q4 and MegaBomb header will really wake these bikes up and make them much more fun to ride (and sound better too!).
All EJK and FMF controllers come pre-programmed to the recommended base light settings for the WR250R/X, which represent typical stage 1 (exhaust + air filter) modifications. It is recommended that you install the EFI controller, take a few test rides, then decide if you want to do any further tuning. Adjustments to the Controller can be made "on the fly" and no computer or other external device is needed to make these tuning adjustments. While tuning the bike yourself is possible, obviously the most accurate way would be to let a qualified shop with a motorcycle dyno do it. We stuck with the pre-programmed base light settings on our WR250R Project Bike and it runs great.
Combining EFI Controllers With Exhaust Systems:
All of the FMF Performance packages we sell for the WR250R/X include an EFI Controller. Combining the EFI controller with a quality aftermarket muffler, mid-pipe, and header will really wake these bikes up, especially in the low to mid-range, making them much more fun to ride (and they'll sound better too!). See links at bottom of this post for details on these performance packages.
Standard Features of the EJK EFI (Electronic Fuel Injection) Controller:
• Simple Plug-n-play installation
• Simple and easy tuning with no dyno required
• Simple Push Button Adjustment Interface
• Does not require a computer or software to tune
• Comes pre-programmed for Stage 1 mods (aftermarket exhaust/intake)
• Load Based Tuning takes into account RATE, TPS and RPM to construct three main zones for fuel adjustment
• "On-the-fly' tuning. You can make fuel adjustments in your garage or on the side of the road
• Does Not Interfere with Stock ECU Operation
• 2 Year Warranty
NOTE: EJK designs and manufactures these controllers and produces private label versions for several companies. This product, with the EJK logo on it, is identical to the one FMF sells with their logo on it.
Where To Buy:
• WR250R EJK Fuel Injection Controller at SRmoto
• WR250R FMF EFI Power Programmer at SRmoto
• WR250R FMF Q4 Performance Package Deal at SRmoto
• WR250R FMF PowerCore 4 Performance Package Deal at SRmoto