Strange Dyno Result - 2010 Honda Hornet 600

[Zen Dog]

Dear depraved inhabitants of BCF. I put my bike on the dyno, and the results are.... odd.

Some context -

Bike is a 2010 Honda CB600F Hornet ABS - https://www.motorcyclenews.com/bike-reviews/honda/cb600f-hornet/2007/ I bought it a couple of months ago. It's in generally very nice condition. It's done 16k miles and just had the valve clearances done. It has a Healtech gear indicator, and a quickshifter (which is ignition only). I don't like the quickshifter so it's been disabled/bypassed and wasn't powered when the dyno run was done. The previous owner fitted a set of aftermarket headers and silencer, replacing the original system. But he didn't get it remapped. This last point is the reason I put it on the dyno, as I was worried it might be running too lean with the reduced backpressure of the new pipe.

So, the dyno graphs. There are 3 runs on the printout.
1 Slow Throttle Roll On
1 Wide Open Throttle (WOT) without load
1 Wide Open Throttle (WOT) with load.

The dyno tester is a specialist in classic bikes, modern FI bikes aren't really his forte. But he didn't seem worried about most of it, particularly the air/fuel ratio which he said was "acceptable". Also the big spike in the WOT load run is because he was getting a dirty signal from the ignition (this is also the reason there is no measured torque), so that can be ignored.

What he did seem very confused about is the power just flatlining at 70hp. This bike is listed as being 100hp (at the crank). That should be around 85hp at the wheel/dyno. He said it looks as though the bike is going to make exactly that, and then it just stops making any more. He asked me if it was electronically limited, or an import, or if I'd heard of any speed limiters applied to this model. As far as I know, none of those things are true, and the bike is completely standard apart from the mods I've mentioned.

I did find this thread on reddit, and the symptoms aren't the same, but I wonder if I could be seeing early signs of this issue - https://www.reddit.com/r/MotorcycleMechanics/comments/1nk8ddx/honda_hornet_600_2012_bike_wont_rev_past_7k_under/

So, what could be the cause? And how can I fix it?
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Current - '94 VFR750FR (Dead), '00 VFR800FI, '10 600 Hornet - Previous - '11 CBF125, '10 Street Triple R, '92 MZ ETZ301, '05 TTR250, NSR125R, KMX125, "Honda" Win
My bike trip around S.E. Asia 2010/2011

[stinkwheel]

The bikes own gear sensor and clutch switch both working as they should? Effectively does the bike know it's in top gear with the clutch out?

They'll sometimes pancake the power curves if the bike thinks it's in got the clutch pulled or is in neutral/a lower gear to stop you rev-bombing it to death or flipping it.

Both systems may have been messed with if you have an aftermarket gear indicator and a quick shifter.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Zen Dog]

[A100man]

[stinkwheel]

[Zen Dog]