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How much bhp could be extracted by a CBR 919
MadMaxx - 5/11/16 at 02:59 PM

As per subject, how many bhp could be obtained by a standard CBR 919 with proper exaust, customer made airbox and dynojetted? 140? 150? More? :-)

On Pistonheads there is an adv for a Megablade rolled at 161 bhp at flywheel. Is it, in your experience, a reasonable and realistic target?

Has somebody experience with rotrex charger applied at CBR 919 without changing the internals and retaining the carbs? Or is it necessary to swap to injection?


mark chandler - 5/11/16 at 06:18 PM

161bhp sounds wildly optimistic... I expect the rolling road was out.

Mine is turbo'd, I have only fitted a lock up clutch apart from that it is as it left the factory mechanically so not reduced compression ratio and it puts out 200bhp on optimax @ 7psi, I have cobbled together fuel injection and have a decent sized intercooler.

Even with HD springs the clutch starts slipping at 175bhp.

The bearings went in my turbo earlier this year so I am replacing with a holshot, this will get mapped in January February so I am hoping to get a little more, it is on the limit of the gearbox.

Problem with a supercharger is getting the drive.


Doctor Derek Doctors - 5/11/16 at 09:30 PM

I spluttered a bit when I read 161bhp. Mine was a full AB Performance engine (Dynjet kit, ram-airbox tuned exhaust etc) and I was told 125-135bhp is what they are good for.

The 919 was always more of a workhorse than a power lump. Great engine but not one for big bhp numbers.

Didn't welderman have a Turbo'd 919 in an LA Gold?


rm0rgan - 6/11/16 at 10:15 AM

quote:
Originally posted by Doctor Derek Doctors
I spluttered a bit when I read 161bhp. Mine was a full AB Performance engine (Dynjet kit, ram-airbox tuned exhaust etc) and I was told 125-135bhp is what they are good for.

The 919 was always more of a workhorse than a power lump. Great engine but not one for big bhp numbers.

Didn't welderman have a Turbo'd 919 in an LA Gold?



Spot on - the quoted BHP for a 919 is 123.0 hp (92 kW) @ 10,500 rpm and that is exactly what my AB engine produced.

They are well suited for sevens and fury's and even with that power. As Colin Chapman used to say 'add lightness'.

https://en.wikipedia.org/wiki/Honda_CBR900RR#CBR900RR_.28919cc.29_SC33

[Edited on 6/11/16 by rm0rgan]


Matt21 - 7/11/16 at 08:49 AM

Without a turbo/charger you'll struggle to get much more power.

I had a Rotrex c15 charger ready to go on mine, but then decided it was easier and cheaper just to switch to a bigger newer engine (which hasnt happened yet)

I had a cunning idea to take the charger drive from the end of the crank shaft where to timing case is, so I machined it out so that it would take an oil seal and a shaft through it that bolted to the crank. Then i found out the crank is slightly offset to the center of the case so it was a no go in the end.

But the turbo option is perfectly viable as others have done (I have one perfect for the job if you're interested)
I priced up doing both turbo and charger and it was around £1200 if you do the fitting yourself. I couldnt get any answers on what to do with the carbs in terms of setting up so was going to see how it ran when it was done.
You can keep the carbs if you get a new aribox that pressurises them, though its not the ideal way, it is possible.