So after my initlial disappointing result here: http://www.ducati851and888.net/showt...ppointing+dyno I made some changes, throwing the Pipercross sock-type filter, that encompassed both TB velocity stacks, in the bin and corrected the valve timing to 104/108 as per Brad Black's brilliant working. (the ol' girl is basically a 96mm 851 with 748R heads/cams, so a 926cc 748R if you will)

I've also added some adjustable length velocity stacks, with a much better flare than the piss poor OEM 851 jobbies. I set the height at the minimum I could without removing any material but they were still approx 20mm longer than stock.

But everything I read seemed to agree that longer was pretty much better....unless you could afford to pull +!3krpm...which I can't. And after seeing this photo, and knowing that John Britten never did anything without a reason, loooooonger=better:

And here we have mine, albeit still pretty stumpy compared to the monster's on John Britten's engine:

And with a free flowing filter at the neck of the intake behind the steering head I ended up with this:

Note, I'm running a Corse intake, 1 piece Corse airbox and Corse tank, so plenty of room under there.

Compared to what I had previously it all looked fairly promising, so another dyno appointment was booked...queue the excitement....aaaaand the result is still pretty ordinary. (see attachment).

The upside is that the torque curve is much more "normal", peaking around the 8.5krpm mark, rather than the strangled 7krpm of the previous setup.

The power/torque curve follows something like Brad's experience with a 748R :
http://www.bikeboy.org/748r.html

With a mini-peak about 9krpm for a 748R (a tad lower with mine thanks to the longer stacks?) flattening off, then starting to ramp up again.....only it absolutely dies in the arse at approx 10krpm. No leaning off, no power tailing off, just hits a wall with a bad miss.

So basically a 748R makes good power thanks to extra revs, and I just need to throw a few more revs at it...only it won't let me. It's built for it, with H-beam Ti Pankl rods, Pistal piston's, balanced rotating assembly, lightweight flywheel yada yada. And it's a race bike, not doing 10's of 1000's of km's/year.

But nothing the cluey guy doing the tuning could do to fix it, so Im thinking the "916+full exhaust" eprom is the culprit? A 916 makes peak power at just 9krpm, the eprom won't be written for +10krpm? Or am I missing something?

So the question is: how do you make a single injector/TB bike rev past 10krpm? I have some other eproms, but they are 916SP that has 2 injectors/TB, where I have just the Strada single injector/TB setup with the fuel pressure reg wound up a tad.

I'm hoping for a simple solution but fear some dual injector TB's and an unobtainium wiring harness to suit are in my future....gawd, so close and yet so far!

PS: apologies for the attached dyno graph, I couldn't figure out how to load a pdf on Imgur, not to mention the dual AF ratio's compromise the actual dyno trace.

851 intake.pdf

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