Direct Port Injection?

With all the EFI they OEM's are starting to implement in their possible 2007 bikes, I wonder why they are not poking around with Direct Port injection. This can be done I assume? It seems like that would make a bigger difference than the EFI setup they are experimenting with now.

Whats next in the dirbike world with these 4-strokes? Hydraulic valves and direct port injection?

What are your ideas and predictions for the next evolution? I wish they would redesign the 2-stroke with direct port injection (no reed valve), they could design them like the Evinrude Engine (It lubes the bottomend like a 4-stroke, has direct port injection (doesn't need ports anymore), yet it is a 2-stroke. It burns cleaner than the 4 stroke engine, while making more power and torque per cc at the same time. I bet that will show up sometime in the near future.

Your thoughts?

Now this is what this forum needs. more interesting posts. :thumbsup: I just found out the other day that the manufacturers were not doing direct port injection. why not? I wish they would just build em like they know how. These things should run like little 450 streetbikes.

Solenoid actuated valves would be nice...

Direct injection is a great technology. The way I understand it is the fuel pressures are so incredibly high that there is a cost in price / weight with all the associated needs: Pumps, heavier lines, etc...

A friend had a fuel pump go bad on a direct injection Diesel motor in a VW. The new pump costs $1100!


Thats true i didn't think about cost. And your right, they need such high pressure. They say if you were to test an injetor ad say you had your finger in front of would inject fuel into your skin due to the high pressure!!

But man...these bikes would rip. I can't even imagine the throttle response :thumbsup:

Solenoid actuated valves would be nice...
It would save weight it seems to me, plus you could tune it with a CD and not need to worry about valve spec.

You would only need that for the exhaust side since direct port would take care of the intake.

What I would give to know advanced math/engine design basics.

Even if they could clean up the two stroke, it would still fall to the fourstrokes because of the traction the fourstroke gets.

When you look at them side by side, a 250 two stroke isnt all that far off HP wise against the 450 but it feels and rides like it because the fourstroke engine allows the tire to bite the ground better.

Yes that is the the classic issue I guess. Torque vs. Weight/Handling.

I miss having all sorts of different bikes at the track. I wish they would bump the displacement to 200cc for the 125, and 285cc for the 250. Their current 144 rule is a joke.

On the dyno the 200cc pinger has near the same Torque curve as the 250f , and the 285cc has near the same amount of Torque as the 450, but it can be tuned for a nice horsepower advantage also. 300cc 2-strokes would be my ultimate dream.

I like having a veriety to choose from. I just wish the rules were different, but what can you do.

I think dirt bikes get too beat up for a system like that. Things would break too often.

They might someday...but for now a throttle body EFI system can be added to an existing engine design, easy & cheap compared to designing an all new head with port injection along with all the other things that go with it. What do you guys think...maybe in 10 years it will be common??

Factory hydro clutches would be nice.

My honda-montesa trials bike is a 250 four stroke with hydro clutch, EFI, and weighs 160 lbs.

as georgestr said reliability, so i guess they would have to build and test the systems like they are and fix all faults before releasing them to the public

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