Power loss after 3/4 throttle

[HoodJesus]

Hi all,
I've got a 2003 hayabusa stock. I've noticed after the last year of owning it that it has a loss of power after 3/4 throttle. The acceleration of the bike slows greatly and almost struggles to gain speed in every gear after reaching around 3/4 throttle. It regains all power and accel when returning below the 3/4 mark but consistently loses power after going above.
I have yet to tear into the bike but am looking for ideas on where to start or if anyone else has run into this issue.
Any and all advice welcome! Thanks in advance!

[Bumblebee]

Welcome........

How many miles are on the bike?

This sounds like a fueling issue.....maybe your fuel filter or injector filters are plugged or partially plugged?

Might sound stupid but check your air filter and spark plugs too as they all work hand in hand.....

[Kiwi Rider]

Hi there, welcome along to our 'technical help line' for newbies!
Certainly sounds most likely a fuel pump/fuel delivery restriction issue.
Quite a common problem from an older machine like yours, especially if they sit for a while in a hibernation state.

Check these items . . .
1) Check fuel pressure from pump
2) Check fuel delivery rate from pump
3) Check injector spray pattern
4) Check and or replace spark plugs (eliminate any possible issues there)
5) Check and or replace air filter (eliminate any restrictions there)

Refer to the service manual for all fuel pump specs, it's all in there, if you do not have a manual someone here will give you a link to an online free manual.

How about introducing yourself and pics of your bike in the new members section of the forum.
Hope ya get it worked out . .

[HoodJesus]

Welcome........

How many miles are on the bike?

This sounds like a fueling issue.....maybe your fuel filter or injector filters are plugged or partially plugged?

Might sound stupid but check your air filter and spark plugs too as they all work hand in hand.....

The bike just hit 23k miles. And yes I will do all of this just need to get the bike apart first. I didn't think of the air filter that's a good idea!

[HoodJesus]

Hi there, welcome along to our 'technical help line' for newbies!
Certainly sounds most likely a fuel pump/fuel delivery restriction issue.
Quite a common problem from an older machine like yours, especially if they sit for a while in a hibernation state.

Check these items . . .
1) Check fuel pressure from pump
2) Check fuel delivery rate from pump
3) Check injector spray pattern
4) Check and or replace spark plugs (eliminate any possible issues there)
5) Check and or replace air filter (eliminate any restrictions there)

Refer to the service manual for all fuel pump specs, it's all in there, if you do not have a manual someone here will give you a link to an online free manual.

How about introducing yourself and pics of your bike in the new members section of the forum.
Hope ya get it worked out . .

Thank you so much for the guidance! First time working on more than an oil change or tires on a bike.
Made a post in newbies check her out!
And that's amazing I didn't realize service manual had all those specs figured I'd have to look online.