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
This past week we installed an FMF Q4 Performance Package on our 2008 Yamaha WR250R. The package consists of an FMF Q4 Slip-On, FMF MegaBomb Header, FMF EFI Power Programmer, and 12oClockLabs EXUP Emulator.
Installation is pretty simple. First you remove the EXUP Cables and Servo Motor from the OEM muffler/mid-pipe, then you un-bolt the OEM header and muffler. We then plugged in the 12oClockLabs EXUP Servo Emulator where the OEM Servo Motor once was, and then bolted up the FMF Q4 Slip-On and MegaBomb header. Everything fit perfectly. Finally, we lifted the gas tank slightly to gain access to where the FMF EFI Programmer Plugs in, then mounted its control unit near the bike's battery. We had the bike up and running in about 45 minutes.
It took less than a mile of riding to feel the benefits of this package. Gone is that dead spot early in the stock WR250R's powerband, and instead you get instant acceleration as soon as you twist the throttle. FMF claims the MegaBomb header increases power across the full powerband (low, mid-range, and top-end) and my butt dyno confirms that.... acceleration is much better, especially at lower RPM's. As for looks, the whole system looks great on the bike, especially the MegaBomb header, which gradually turns to a bronze-like color.
The sound of the system is excellent... louder than stock, but not painfully loud like many of the exhaust systems on the market. In fact, of the four systems I've tried on these bikes, this is the first one that doesn't need a low noise insert to quiet it down. You can thank the technology FMF uses in the Q4 muffler for the aggressive, but not-too-loud, sound the system produces.
After about 250 miles of riding, I think the FMF Q4 with MegaBomb header is the best available exhaust system for the 2008+ Yamaha WR250R. You definitely feel more low to mid-range power, which these bikes really need. Fit and finish is typical FMF, and the system sounds great... it's louder than stock, but not painfully loud like some exhausts. I couldn't be happier with this system and can't believe I waited two years to replace the OEM exhaust!
Where To Buy:
• FMF Q4 Performance Package at SRmoto