Its dyno time baby! Now with added results

[Whosthedaddy]

The following is a graph of the ZX7R as it should be, well a US one and a few ponies shy of the figures that Parkers and MCN state it should have, but a power curve none the less.

https://images.sportrider.com/bikes/dyno-2000-kaw-zx-7r.gif

I never really noticed it until somone mentioned it after riding my bike, theres quite a few flat spots at low to mid range with the occasional bogging down before going bananas again.

Secondly, I swear it should accelerate harder than it does at the moment.

I don't like to really give it some in 1st as not too keen on the idea of the front lifting unexpectantly, but coming out of a slip road or from a standing start the bike seems to run out of steam (11-12,000 revs) in 1st at 50 odd with 2nd gear peaking at 80mph. I could get the ZXR to hit 100mph on the clocks in 2nd and I assume that the 7 should be pulling equal speeds if not a little better.

Both of the above should by my knowldge be down to fueling and carburation. Could the above also be key pieces of evidence that would suggest why the bike still doesn't like starting when the engine temperature is medium to hot, say midway up the temp gauge but starts fine when cold?

I've found a local workshop that does race preparation for bikes and has a dyno, for the price of a few quid I want a go to see how the 7's running and what could be done to improve it.

My question, what could be done (hypothetically at this stage) to improve the running of the bike.

If I remember correctly I believe the bike may have been re jetted previously, is there a limit to the amount of tinkering that can be realistically done?

Do the flat spots affect both power and torque or just the ability for the bike to rev in a smooth manner?

Should I start taking guess' to what the bhp is.

[SoND]

What sort of miles is on it?

Clean, balance and set up carbs if they need done.

Clean/replace air and fuel filters.

Compression good?

Set valve clearances.

Are the valves seating properly without leaks? Could clean them and the head up or get them cut when you're in there.

Got a race can on it? If not it could help.

Is the exhaust leaking at all?
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Go back to bed - You have no rights - "Streetfighters ~ Mainstream motorcycling's crackwhore sister."

[Whosthedaddy]

22-23,000miles with the last 8k being in my uneventful ownership.

It has a full system and K&N filter. The fuel filter was changed this time last year in the service, but because it was an aftermarket air filter, they left alone.

I have no idea of the state of play with valves or if they have even been done in its lifetime. Having already owned a ZXR that ended in disaster with a valve / piston / head interface and resulting in an immediate engine failure, not too keen on this one going the same way.

The engine sounds 'Kawasaki' like but no iffy noises, rattles or tapping like the previous bike.

[SoND]

With those miles if you haven't paid for the valves I doubt they've been touched.

Maybe the dyno could solve all your problems, maybe not. Good luck.

My guess is 100hp
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Go back to bed - You have no rights - "Streetfighters ~ Mainstream motorcycling's crackwhore sister."

[Whosthedaddy]

I'd hope for a ton, but not too sure it will.

[Whosthedaddy]

Like an excited boy waiting for Christmas to arrive, today finally came. The 7R was off to the dyno!

I had a little tightness in the stomach as would the bike behave in the workshop as it still has a displeasure to starting when hot*, but in no time the bike was up, strapped down and ready to go.

I would have loved to have filmed it but I think it would have come over a little nerdy as I peered through the inspection window.

A few warm up revs and through the box to get things started and already I start beaming like a Cheshire cat at the noise of it. Up and down the box, to the red line before free-wheeling it back down to start once more all the time being accompanied by spitting flames from the exhausts.

The results were as clear as day on the screen and made me smile even more when I see the bhp result.

https://w3.bikepics.com/pics/2008%5C10%5C21%5Cbikepics-1456548-800.jpg

Stock according to the manuals, 123bhp, mine after 10 years and 23,000miles, 115bhp at the rear wheel. All I wanted was a 100, and it has!

Top speed appears to have taken a hammering? The power is still there but the speed isn't? Would have been interesting to see the torque and split times for 0-62mph, 1/4 mile and the likes but that can be for next time.

It was quite clear that my suspicions about a flat spot at 4,000 revs was justified. With the front wheel tethered firm the bike shook as it compressed the suspension hard as it jittered to make progress. Once the spot was passed, it just took off like a rocket.

Fuelling suggests that its a little rich at the top end, not by much but a little more than they would set the carbs to if they were to be tuned, and obviously lean when bogging down.

Treatment, not a lot unless I want a full carb assessment as may need the jetting sorted depending on what's been done in the past.

I even had the chain lubed and the gear linkage tinkered with to allow for smoother transition up and down the box.

* True to form the bike just turned and turned like a lemon only starting with a bump on the rolling road? He suspected it was maybe an inlet problem staying open ever so slightly?

£35 well spent, many thanks to www.mistralperformance.co.uk

[Wafer_Thin_Ham]

Good results.
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[Whosthedaddy]

[Keir]

did they check the air/fuel ratio and torque curve?
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Current : '08 Yamaha FZ1s
Previous: '99 Honda CBR 600FX, 03 ZX636 B1H, 99 Fazer 600 (red), 02 GSX-R 600 K2, 00 SV650s (red), 2008 ZX10R, 97 Bandit 1200N, 04 ZX6RR K1H, 04 GSX-R 1000, 98 Fazer 600 (gold), 05 Madness 110 Pit bike, 04 CR125R, 00 SV650s (black), 06 KTM 625 SMC, 99 SRAD 600 track bike, 03 SV650, 98 Bandit 1200N, Bandit 600SY, 03 GSX-R 600 K3, 01 GSX-R 600, 01 Fazer 600 (black), VFR 400 NC30 x3, 78 Honda Dream, 00 Speedfight 50

[Whosthedaddy]

[Kickstart]

[Keir]

personally id be happy, regardless of the power figue, knowing that the fuelling is fine and not about to lunch the engine with the exhaust and filter etc maybe leaning it it up a bit.

Power looks good, think manufacturers quote crank power usually dont they? so 123bhp may be at the crank so in turn 115 at the wheel may be very good and hardly any lost at all.... if you get my drift!

on a side note, are you still round these parts? thought you was selling up?
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Current : '08 Yamaha FZ1s
Previous: '99 Honda CBR 600FX, 03 ZX636 B1H, 99 Fazer 600 (red), 02 GSX-R 600 K2, 00 SV650s (red), 2008 ZX10R, 97 Bandit 1200N, 04 ZX6RR K1H, 04 GSX-R 1000, 98 Fazer 600 (gold), 05 Madness 110 Pit bike, 04 CR125R, 00 SV650s (black), 06 KTM 625 SMC, 99 SRAD 600 track bike, 03 SV650, 98 Bandit 1200N, Bandit 600SY, 03 GSX-R 600 K3, 01 GSX-R 600, 01 Fazer 600 (black), VFR 400 NC30 x3, 78 Honda Dream, 00 Speedfight 50

[Keir]

[Whosthedaddy]

I am well chuffed at how straight and true the power is laid down and as I said, not too shabby for a 10 year old bike.

Its another thing to ad to the eventual eBay ad as well.

[Whosthedaddy]

[Kickstart]

Hi

Assuming the dyno run was done in 4th gear and stock sprockets, here is the power and torque graphs:-

https://www.bikegraph.co.uk/TorqueGraph.php?Id=70&x_max=800&y_max=500

(based on me reading the power values from your graph).

And the thrust through the gears:-

https://www.bikegraph.co.uk/TorqueThrustGraphMulti.php?x_max=800&y_max=500&Id1=70&FrontSprocket1=16&RearSprocket1=43&drag=yes&cd=3.6

If you go here you can play with the effects on the rear wheel thrust from changing the gearing.

https://www.bikegraph.co.uk/TorqueGraphs.php

Shimmed valves are not normally that cheap to do. But depends on the bike design. Some Kawasakis have rocker arms that can be pushed to one side to get at the shims.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Keir]

[Wafer_Thin_Ham]

[Coxyzxr]

An adjustable ignition advancer or perhaps just the +4 across the board (if you don't tinker much) should fill in a couple of the dips a little better and should help quite a bit with the top end richness.
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**WAS FITTED "WRONG WAY ROUND" !** CANT ACCOUNT FOR THE STUPID !

[Whosthedaddy]

Keith, you the man, cheers!

Big_Ham, I am very surprised that the IL4 750 is putting out the same power give or take a few as the twin that was the Mile. Funny that flat spots occur at a similar rev range.

Riding both, I'd imagine a different story though.

[Pete.]

Mistral are renowned for their engine-building expertise. Did you get a peek in the engine-bay, usually have half a dozen 'busa engines in there being worked-on
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[Whosthedaddy]

Bits everywhere!

Had a Busa tucked up in the corner, kept looking at it and wanting to ask more about it but felt a little shy. He said that he is working on engine powered cars mainly, 1600cc Busa engined cars.

[Pete.]

Yeah he does a lot of cars, from engines to full-builds. Nice guy too
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[Wafer_Thin_Ham]

[Kickstart]

Hi

Limited data on this site, but might be interesting:-

https://www.deeknow.com/dyno/index.php?bike1=RSVR_2004&bike2=ZX7R_1996&action=Dyno+It

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing