I was lucky enough to get my Grom in the first U.S. shipment late last August. Even though that was only four months ago, it seems like I have been waiting forever for performance parts for the Grom to start hitting the market. There are now several aftermarket exhaust systems on the market and a few easy intake tweaks that can be done, but we have needed a reliable and easy to use fuel controller to make intake and exhaust mods actually perform.
So I am very excited about finally getting the EJK Electronic Jet Kit by Dobeck Performance. I chose to wait for the EJK to hit the market because the manufacturer lists features that meet my personal requirements - full adjustabilty without the need for a Dyno. These requirements are probably the same for 95% of all Grom owners. The adjustments are "load based" so this also means that this type of controller and it's performance is subject to the individual rider's "Butt-dyno" which is the only one that really matters for normal street riding and shenanigans. Of course you can still go to a dyno shop and tune your Grom with the EJK. In fact, because of the easy push-button interface, dialing in the power should be easy and take less time while on the dyno machine.
The install was ridiculously easy. The most difficult part was removing the body panels from the bike LOL! Event though the install was easy, the installation instructions are thorough and clear. There are even some helpful pictures on the instructions that will guide you through the body panel removal (if you have never done that, the pics are great) and where to find the factory plugs on the bike. There are just two plugs to swap - the injector and the 02 sensor. The only thing to do is route the two wire harnesses through the bike, unplug the injector/02 sensor, and plug them back inline on the EJK harness and boom - Bob's your uncle. Even if you have never done anything like this, it should take less than an hour, including removing and replacing the body panels. An experienced tweaker could do it in about 20 minutes.
The included instructions work fine and I also posted a how-to with additional pictures over here:
I am impressed with the quality of the plugs and connectors that come with the EJK kit. The fact that they are exact matches to the Honda connectors on the Grom add to the simplicity of the install. I also believe that they made the wire harnesses exactly the right length - not too short and not too long. The exception to this might be the ground wire. The ground wire is extra long. I believe this is in case you want to mount the EJK unit at the front of the bike - like on the handlebar clamps - but still reach the recommended ground point just behind the gas tank. EJK claims that the controller can be adjusted with the buttons while riding, which while that may be the optimal way to adjust under load, is not exactly safe, especially on a squirrely little bike like a Grom. I chose to mount the unit under the seat and for safety reasons, that is what I recommend.
The EJK unit itself is a good size and has clear and well spaced buttons, but is not made specifically to fit under a Grom seat. The EJK unit is not too big, but under the seat the Grom has a toolkit holder that wants to be right where the EJK unit wants to lay. I remedied that with Dr. Dremel's plastic surgery (as seen in link above) but you may opt to just set the unit in the tool kit space at an angle and secure it with chewing gum, or hot glue, etc. It would also fit nicely on top of the handlebar clamps but again, that is not advised for safety reasons.
The instructions for adjusting the tune on the EJK may seem a little wacky at first. In fact when I first read them online a couple months before I got the unit, I was a little turned off. There is also a youtube video but, in my opinion, even it does not explain what the settings do. Luckily the guys at EJK/Dobeck have put a great effort in to their web support presence and posted an excellent hands-on tuning simulator here:
Electronic Jet Kit General Tuning Advice
. This interactive demo really made the lightbulb come on over my head and it made the written instructions and the youtube video make perfect sense!
I highly recommend you go try the interactive demo out. As you go through the buttons on the right side of the screen, watch the graph(ic) on the left side of the screen and you will instantly see what you are doing to the fuel in a graphic way. I played with this for a few minutes and that allowed me to use the printed tuning instructions as a reference while on the road tuning.
Doing the butt-dyno is an iterative process but that just gives you another reason to ride the little Grommy! The process is to ride the snot out of it and pay close attention to what it does or dosn't do at certain times. I found it is best to have a set route or course that you repeat. Ride the course three times before you install the unit and pay attention to any bogs, or power "leaks" in all gears, on straightaways and curves. Then, after the install, keep the EJK factory level one tune, and ride the course three more times and feel the joy. Also pay attention - that is key. This is your God-given butt-dyno and you don't get a print out after every lap, so you have to pay attention. Note that you have to adjust the tune with the bike running so you might want to bring your spare Grom key so you can unlatch the seat while the engine is idling.
Then, following what you learned on the interactive demo and the tuning tips in the instructions, try to change a setting or two, then ride your course three more times - rinse -repeat. I found the factory tune to be rocket ship awesome up to about 50mph so my first adjustment was to the the RED (WOT) zone and to the yellow/blue (transitional) zone between acceleration and WOT. Understand that this will be different for each individual rider so my numbers wont mean much to most people but I will say that to get the WOT response that I wanted on a particular part of my course, I actually REDUCED or pulled fuel from the RED zone, meaning that I was able to lean the bike out at WOT. This will make perfect sense once you try the interactive demo.
My tuning is not complete and the great part is, it never has to be! In theory, I should be able to get used to what the tune settings are doing on my test course, then use that info to tune wherever I ride - in the mountains or in the valley. A card with the default tune numbers to keep with the bike is included. If you ever forget what your tune was and want to go back to EJK default, just refer to the card or go here:
EFI Controllers - Electronic Jet Kit - Motorcycles, ATVs, UTVs, Sportbikes, Snowmobiles, Watercraft, Dirt Bikes
I will finish this review by saying that I have no other fuel controller to compare this to, so I can't honestly say whether it is better or worse than anything else on the market for the Grom. However I can say that it dose not require welding a bungholio on your exhaust and dose not really require anything other than to ride and pay attention to what your ass is telling you. If it puckers, you've got the setting right! I perceived a noticeable increase in performance from starting off the line, to accelerating out of a curve without downshifting like I used to have to do, to getting up to top speed in about 80% of the time it took before the EJK install. It does what I hoped it would do. My butt-dyno can't give me a print out to share any peak HP numbers but the EJK makes me and my butt happy. I believe the EJK is definitely worth $250.