Fuel Injection, what are your thoughts?

[flyboy1294]

Just curious on what everyone's real world experiences are with fuel injection in an off-road application. Specifically used with engine upgrades.

Personally, I have only ridden stock utility quads with FI, so I could scarcely notice a difference from the carburetored quads. I resent the added complexity of injectors and programmers, but at the same time, if it helps meet the EPA's ever-so-strict guidelines I am all for it. I have already heard that the 400ex and LTR450 were going to be discontinued in the next several years because of poor emissions ratings. :(

So, with that said, what do you guys think?

[blholtz]

You already can't get a Ltr. The problem there, the way I understand it was due to the ease of acessing the race map installed is the computer. Why Suzuki couldn't call it for "closed course use only" Like they do dirt bikes is beyond me.

But as to FI I like mine. There is a definite learning curve to dealing with it but I like it. And the Power Commander FI controllers are really easy to deal with IMO.

[Stiles86]

ive had good and bad results with fi.... had a couple of races where electrical isues screwed me ive gone back to carb for simpicity..

[hondaracer_34]

Like stated above, its a definite learning curve. Its fun to learn what FI can do and how far you can go with it. I have had good and bad results with FI. I sent the wire harness off my kfx450r to BCS performance and had them gut it to make it a race ready harness. I haven't had any problems with my electrical since then.

[hontrx265r]

I don't think efi is an advantage at all times, but it is convenient, when you do drastically change locations. I'm more interested in using the timing adj, along with fuel control to really fine tune a setup. However this is something I don't trust many shops with and I don't have a dyno in my garage... I don't have anything against carbs I think a well tuned fcr works fine. But it is nice to not get dirty and just plug the ol laptop in.
Curious what exactly are you "gutting" in your harness? unless your getting rid of electric start, battery, etc... I don't see advantages to just removing the light circuts, and changing the start and kill?

[hondaracer_34]

Some relays, the tip over switch is being bypassed, added a dirt bike kill switch, put in a pingle killswitch, removed lights, and other wires, I forget the rest.

[fastrnrik]

I have a little experience with FI vs carbs....

Bought an 08 Kawi 450 brand new in late 07 to build a TT bike. Took it straight from the dealer to to a "well known" builder who builds (or did build...) national level MX motors. He had built some fast Hondas and at the time was having good luck with making the Suzuki FI motors make good #'s. Then we played the waiting game. He finally got around to working on it & dyno'ing it. It ran ok, then not good, then ok, then blew up on dyno. At this point he wanted me to ditch the Kawi FI and put an FCR carb on it. I almost did it too. I was sick of the FI crap causing problems and wanted the simplicity of the carb. I went out and bought the carb & everything.
Around this time one of my friends who owned a local ATV & street bike shop, and has years of experience racing and tuning motoGP motorcycles, told me to bring it to his shop and he would get the motor AND FI right. I've raced quads with this guy for years so he knows how a quad is supposed to make power. So, I picked up my Kawi (in boxes no less...) and took it to the street bike guy.
The street bike guys don't see the big deal about FI, especially the very simple systems like the quads have now. Motorcycles have had FI for years, so to these guys its just no big deal.
To make a long story short, he did an amazing job. They dyno'd it and mapped it until it is literally perfect. It is so smooth and pulls so hard through the entire RPM range. I could not be happier.
My advice to anyone building a FI motor is to spend the money and have it tuned and mapped by someone who knows what they're doing. Sure a "generic" map that you download off the internet may be "OK", but to get the most out of your FI system, have it done right. You won't regret the money spent.
As far as gutting the harness and all that... I wanted to install kill switch- pulled the hood and looked at the wiring and decided right there to order the Baldwin kit which is a plug&play type deal. Too much risk to be splicing wires for me (I'm an electrical idiot) The Pro's may need every ounce of weight shaved and benefit from a gutted harness, but for the average Johnny A class racer I don't see any advantage to gutting the harness, and the average trail rider should never even have to touch his harness. Just waterproof and secure your connections and leave it alone.
Just my $.02

[hondaracer_34]

I was thinking of going to a carb, but I want to give this FI a chance.

I did the wire gutting just because I didnt want anymore problems from crap I didnt need. I had installed the Pro Design kill switch to my kawi, which involved me cutting/splicing into the coil and saudering. After a few months, I started having problems because of it. So my harness went to BCS.

I think I know enough about FI, but im still learning. Its interesting, and you guys are right, its all about the "right guy." When I get mine dynoed, its going to MXP.

[fastrnrik]

Thats why I spent the $140 on the Baldwin kill switch kit. To help alleviate any of those types of problems, because like I said- I'm an electrical idiot LOL. My bike was built to be a national TT bike. We considered cutting the harness down when we were lightening the bike up, but decided against it. The risk of frying something or screwing something up wasn't worth it to us at the time, and we cut plenty of weight in other places. At the time the Kawi was still real new to everyone and I wasn't aware of being able to send the harness off to anyone to have it cleaned up & cut down. Now there's several places I've seen to send it- BCS, Baldwin, I'm sure MXP does it, etc. If I was still racing myself I'd probably have it done, but my bikes just sit in the corner now. My son races mini quads and they take up ALL my free time! LOL

Good Luck with it. If you're racing a Kawi I would seriously make your subframe adjustable so it can be lowered. That was the one thing that helped the handling the most. Night & day difference. It's cheap & easy to do too.