Toying with EFI.......

[Goinphaster]

Crap. It took all of two seconds to figure out that the GSR TB's won't work once I got them close to the intake tract of a cylinder head I have laying around. The problem is the Mold/set of TB's are not spaced far enough apart to line up with the intake ports of each cylinder head. The reason is simple when you look at the inline 4- theey don't have to deal with gear drive for the camshafts between the cylinders as we do with the V4.

Of interest though is that the TB's fit perfectly into the rubber carb boots of the NC. This would mean that if we could find some 400 TB's that are spaced correctly, then they would mate up nicely. Wonder if VTR250 TB's would work? Need to find some pics........

[amorti]

Any reason you couldn't sleeve down the Triumph TB's? They are separate castings, you can space them however you want...

[Goinphaster]

Maybe not all is lost.....

One of the things I noticed about the GSR400 TB's is that the casting for each pair of TB's there is plenty of sturdy structural material. This brought me to the idea that maybe I could cut the castings in half creating four separate TB's, and the only things needed to make them operate would be;

1. *new butterfly valve shaft(s) (plural if i wanted to use the secondary butterfly's) for the required spacing*,

2. fuel rail for the injectors,

3. Linkages to make them open at the same time.

I looked up pics of an NC42 (CB400 with EFI) TB's and this is not possible as Honda is using a different style of TB's. They could not be possibly cut in half like the GSR's, it looks like the have some sort of plumbing in between each set TB's integrated into the castings.

*New shaft(s) would be fairly easy for any Machinist to manufacture, especially if the original were to be given as an example. From the looks of it, they would need to machine the flat spots for the valves to screw into and then Machine the ends to accept the Throttle Linkage and the other to accept the Throttle Position Sensor.

I have the Camera on the charger so I can take some pics and put theory into images for the more mechanically experienced to peruse.

Not throwing in the towel yet..........

Of other note, the GSR400 TB's taper down from the opening at the Secondary BV's to the primary BV's.

[gonzothegreat]

Have you seen this post viewtopic.php?f=24&t=11032 ?

[Goinphaster]

thanks for the link. I searched GSR400 throttle bodies but didn't look at searching for EFI projects. I just hope that I will have as much luck as him.

[gonzothegreat]

What would be really cool to have is the ignition/fuel table off a CDI

[mruehl34]

Oh Oh,

i will try it to explain with my worst school english and google translator. So nobody´s perfect.
It is not easy to fit throttle bodies to a RVF/VFR 400, it is easier to fit them on a 4 cylinder inline engine.
The problem we have, is that the bodies open (front and rear cylinder) and close in the same angele. Try it!!
the throttle setting must be the same everywhere.
Then you must separate if you want a fully sequential injection or half sequential injection. RVF don´t have a camshaft sensor.

This is the first step, you must decide what you want.
Then next step.


Michael

[Goinphaster]

this is the first step, you must decide what you want.
Then next step.

I definitely want this The journey is half the fun, right?......... Right?

[venom51]

I'd love to end up injected. I have been looking at ways to modify a stock set of carbs in a manner that we could get injectors into them while retaining the fucntionality of the slides. Primarily to keep the air velocity up as the throttle is opened. If you look back at the first couple years the R6 was injected they used this setup for what I believe to be that very reason.

If we can sort out a good path for the dealing with getting the mechanical portion right than we'll use a Microsquirt and a cam sensor to achieve sequintial injection.

I unfortunately spent the last year with the bike in a non running state so I plan to race this year and won't be taking the bike back out of service until it breaks again.

[Cammo]

I have been looking at ways to modify a stock set of carbs in a manner that we could get injectors into them while retaining the fucntionality of the slides. Primarily to keep the air velocity up as the throttle is opened. If you look back at the first couple years the R6 was injected they used this setup for what I believe to be that very reason.

The early injected motogp M1's (after the flatslides) also used this slide setup I believe!