General Discussion Forum

Listenong to my DMXS podcast last night I heard Mitch payton let something slip during his interview.  When asked what he sees as the next biggest change in dirt bikes he said "With 3 manufacturers having fuel injection..."

We know Suzuki already has FI, and Kawasaki has released the info on their bike getting FI this year.  Both Yamaha and KTM have released info on next years bikes indicating they will not have FI.  That leaves Honda who is not slated to release any info on their new bikes until September.  

So for all the Honda riders out there, which is the vast majority of riders (based on bike sales).  You can expect to see CRF450s with fuel injection next year.  

Bill H. 2000 CR250R

Bill, has Suzuki yet to release their 08 450?  

Let's be clear about the implications of EFI with an MX bike...

I don't see any of the manufacturors implementing a 'closed loop' EFI.  That being said, the systems will have no way of re-calibrating themselves to adjust for every conceivable change.

For example, the typical Open Loop EFI relies on a pre-programmed map of TPS, ignition, and injector pulse width/duration.  Although they have a MAP sensor, the system cannot read the O2 lamda in the exhaust stream, therefore the EFO controlloer has no idea whether it's running rich or lean.  If you take one of these bikes up to altitude, or put a free-flowing pipe on it, the MAP can make minor adjustments but dialing it in will require reprogramming of the maps (whereas on carbureted models, you change the jetting).
I for one am not entirely sold on EFI for MX bikes.  Throttle response will suffer (analog vs digital), as well as potential for quirky response from off-throttle to on.  Finally, the cost factor and cost-of-replacement must be take into account.

Bill, I know you are relaying info, and were not taking a stance of Pro vs Con of EFI, but it's worth mentioning, so I did ...  
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But Skip why then are Fi Snowmachines so popular?

especially mountain versions which change altitude constantly.  

Snowmobiles use a closed-loop system.  
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So the factory teams will be able to program there bikes as needed or to suit the conditions, But joeschmo will be stuck w/ the factory program, unless joe schmo has a laptop and the ability to reprogram his own bike.  
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Nobody's gonna hurt anybody. We're gonna be like little Fonzies here. And what's Fonzie like? Come on what's Fonzie like?

You got it!  
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Well.....U can buy EFI systems with mulitple maps and aftermarket companies already have systems for different settings.

Snowmobiles run a battery most times and dirtbikes run batteryless  EFI Correct?

Someday u will be able to change ur dirtbikes batteryless efi igniton map with ur cell phone or GPS.    

I welcome your discussion on the subject Skipper.  I too am very interested in the pros and cons of EFI and the DFI (Direct Fuel Injection) for 2 stroke engines.

I have witnessed the wonders EFI has done for snowmobiles, but dirtbikes (motocrossers especially) put different demands on an engine than a snowmobile.  We are on and off the gas more often and spend much less time with the throttle wide open.  Sleds do not require the same kind of throttle response we have come to demand from dirtbikes.  

I have not had a chance to ride the new Suzuki so I cannot compare the two technologies myself yet.  The factories seem to think this is the way of the future so until we start our own factory we are along for the ride.  

I will state that change for the sake of change is not always the best policy.  Look at what has happened with the fourstroke movement.  

Bill H. 2000 CR250R

"I will state that change for the sake of change is not always the best policy.  Look at what has happened with the fourstroke movement.   "

I couldn't have said it better if I tried  
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