Hayabusa loses power above 6500 rpm

torrey.smith

torrey.smith

)'(
EDIT: Problem solved by replacing Fuel Filter and Fuel Strainer.

Hey guys/gals, I'd appreciate some advice for this problem:

2002 Hayabusa, around 6500 rpm the power diminishes significantly.

It will rev beyond that point, but it seems to really bog down.

This is a new symptom that I noticed after returning from SBK at Miller Motorsports (1730+ miles).

I have not replaced or cleaned the air or oil filters in the 10K miles that I have owned the bike (Bike has 38K miles total). My buddies have said that needs to be done in intervals of around 10K miles.

Thoughts?
 
Last edited:
Burning1

Burning1

I'm scareoused!
First thing that comes to mind is an ignition advance issue... But the ignition systems on these machines are pretty damn reliable.

If I were you, I'd start by reading the ECU error codes. This can be accomplished by jumping a pin on a connector near the ECU. With a Google search you can find the procedure for your bike.

Since you've never changed the air and oil filters, I'm going to take a shot in the dark and guess you've never done the valves as well; so it's possible they've never been adjusted.
 
396

396

Well-known member
Sounds like you need to start with the basic maintenance and then go from there. PM me if you want. I work on Busa's.
 
hitman5532

hitman5532

The Anti-Squid
It is losing power, or is the clutch slipping and the engine is no longer driving the rear wheel while still winding up?
 
Marlowe

Marlowe

Beer Whisperer
I'd start with the air filter. Then figure out what other deferred maintenance you've been blowing off that needs to be done.
 
torrey.smith

torrey.smith

)'(
Thanks, Guys. This is a good start for me on some stuff that needs to be done.

I'm not sure exactly what triggered it, but the 1730 mile trip was immediately before the problem.

Clutch is a possibility, but it doesn't remind me of how that felt on a previous bike.
 
Enchanter

Enchanter

Ghost in The Machine
Staff member
Check the simple things first. Air filter, fuel filter, loose or pinched hoses, ram-air ducts, emission control (canister), fuel tank vent, etc. If it was the clutch, the engine speed would rise without a corresponding rise in road speed. It's not the oil, and it's not the valves.

Ride in the rain recently? Has the bike been apart recently? (rhetorical questions)
 
B

Bronto

Well-known member
Something else to try. Run some fuel injector cleaner gas treatment.
If you want to get into it. Pull the fuel rail off the injectors. Clean the little micro filters on each injector. They collect lint like material. Don't have to remove the injectors, access to the micro filters are at the fuel rail connection. Condition the O-rings with a Teflon oil, like Tri-Flow.
Have to see the factory manual has a troubleshoot for lose of power at high rpm. Cause a Busa should be the inverse, it becomes insanely powerful at those RPMs.
 
B

Bronto

Well-known member
Oh yeah, something else. Mistake made at the gas station, using the green hose and not the black one :laughing

Surprisingly the bike runs, billows allot of smoke. But has not high end power.
 
rapidrobbie

rapidrobbie

Ride Fast Take Chances
check fuel pressure and make sure secondary butterflies are opening,one other thing to ckeck is water in the fuel
 
B

Bronto

Well-known member
Troubleshooting chart for lose of power at high speed.
All the sensors can effect it. Use dealer mode diagnostic to narrow it down.
A vacuum leak from one of the throttle body hoses or devices hooked to them.
The flapper valve inside the airbox isn't operating. A vacuum hose leak or defective flapper solenoid.
Sparkplugs gap too close or defective coil.
Valve tappet clearance too close.
Fuel injectors clogged or fuel pump pressure low.
Throttle body boots allowing air to enter.
Clogged air filter.
Generally fuel delivery that is low effects high rpm performance.
If your using aftermarket fuel injector module like a power commander. Check its mapping. The ECU can be defective, it'll be picked up deal mode diagnostics.
Sensors from crankshaft sensor to throttle body position sensor. All the fuel related sensors from air pressure sensor to oxygen map sensor re suspect.
Most serious is piston rings worn that are leaking through to the crankcase. Weak valve springs or bad valve seating.
The mileage 38k the engine is still a teenager. A valve tappet clearance job if not done already is due.
 
Cycle61

Cycle61

What the shit is this...
Bronto said:
Oh yeah, something else. Mistake made at the gas station, using the green hose and not the black one :laughing

Surprisingly the bike runs, billows allot of smoke. But has not high end power.
Click to expand...

:wow:wow:wow
 
B

Bronto

Well-known member
Not naming names. On a group ride, someone filled up with diesel :laughing
Later down the road, hmm the bike doesn't seem to be running right :D
Field repair, drained out the tank. We even have picture of the fill up. :laughing
 
NorCalBusa

NorCalBusa

Member #294
Enchanter said:
Check the simple things first. Air filter, fuel filter, loose or pinched hoses, ram-air ducts, emission control (canister), fuel tank vent, etc.
Click to expand...

FTW!

Does the bike have any mods? Power Commander? TRE? Both notorious for fubaring an otherwise perfectly running machine.
 
torrey.smith

torrey.smith

)'(
The fuel strainer was cut and the fuel filter was severely clogged. I replaced them and will be reinstalling everything tomorrow.

The resistance of the new fuel filter is amazingly low compared to what I had!

The bike was overdue for this part, go figure.

I will report what the effect is soon.
 
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