2001 Busa Loses Power and Blows Fuel Fuse

M

MadAtThisBusa

Registered
I’ve got a 2001 Hayabusa I’ve been rebuilding for the better part of 6 months.

Took it on the road today and ran fine for about 20 minutes before it seemed like a small power loss. 6th gear tried to give it some throttle (full throttle). Sounded like it slipped or burped around 7k rpm then fuel pump died completely, blinking FI light and no start.
Found that I blew a fuel fuse, replaced it and it ran home but still felt like it was running at 80% power.

New fuel pump, fuel pump relay, clutch, gas tank, battery etc. It does have a PC5 and a straight pipe sidewinder
I’ve had what feels like a clutch slipping problem at 7k to 8k RPM, full throttle and the bike doesn’t respond well, almost like it’s in neutral after 7K.

Bled the clutch line, slave cylinder rebuild, new clutch but none of that would blow a fuse when giving it throttle.

What would cause a fuse to blow at 7k rpm and what could be causing this power loss?
 
I’m leaning towards fuel delivery problem or electrical problem in relation to the fuel system. Definitely need some input though
 
Fuses blow when too much current flows thru them, more than the fuse is rated for.
The cause of that problem is usually a dead short to ground.
But it can also be when an electric motor (fuel pump motor) is strained and drawing a lot of current to keep turning.
The cause of that can be the fuel filter is so blocked the pump motor is working extremely hard to suck the fuel thru the filter paper and maintain fuel pressure.
Or…. The pump motor itself has an internal short causing it to blow the fuse.
The fuel pressure and delivery will suffer and cause a loss of power in the upper rev range creating the symptoms you are experiencing.
 
Kiwi Rider said:
Fuses blow when too much current flows thru them, more than the fuse is rated for.
The cause of that problem is usually a dead short to ground.
But it can also be when an electric motor (fuel pump motor) is strained and drawing a lot of current to keep turning.
The cause of that can be the fuel filter is so blocked the pump motor is working extremely hard to suck the fuel thru the filter paper and maintain fuel pressure.
Or…. The pump motor itself has an internal short causing it to blow the fuse.
The fuel pressure and delivery will suffer and cause a loss of power in the upper rev range creating the symptoms you are experiencing.
Click to expand...
I got to thinking about this as well....

I recall one time I put an external in line fuel filter on one of my bikes that didn't have enough flow which starved my bike at mid-to-full throttle....

I chased that around for a bit not thinking it was that fuel filter because it was brand new.....

As a last resort I took it off and the bike acted as normal....then I got a filter that was rated for the flow....

Maybe.......
 
Fuel pump motor having an internal short or fuel filter are where my mind went until yesterday.
Took it out to give it some throttle and test if the fuse really blows at full throttle and it did. Came back and this was my process -

1) Remove 10A Fuel Fuse
2) Tried a 15A and 20A Fuse
3) Turn Key and Ignition Switch
4) Immediately blew both

So I disconnected the PC5, messed with the ground a little bit, installed another 10A fuse for fuel, and it started right up. Made it home with no blown fuse but haven’t ripped on it yet. Is it possible the PC5 is causing my Fuel Fuse to Blow? Maybe my ground is messing up?
 
MadAtThisBusa said:
Fuel pump motor having an internal short or fuel filter are where my mind went until yesterday.
Took it out to give it some throttle and test if the fuse really blows at full throttle and it did. Came back and this was my process -

1) Remove 10A Fuel Fuse
2) Tried a 15A and 20A Fuse
3) Turn Key and Ignition Switch
4) Immediately blew both

So I disconnected the PC5, messed with the ground a little bit, installed another 10A fuse for fuel, and it started right up. Made it home with no blown fuse but haven’t ripped on it yet. Is it possible the PC5 is causing my Fuel Fuse to Blow? Maybe my ground is messing up?
Click to expand...
Sometimes these aftermarket fuel programmers do weird things....

Last summer I had my Bazzaz crap out and leave me on the side of the road....I managed to get home by doing short leaps...

I chased that gremlin around and it never came to my mind that the Bazzaz went bad....it dawned on me that something was up when I plugged it into my laptop and it wouldn't read the system.....

I took it off and the bike has run perfectly ever since....
 
What was the bike's condition before you started working on it?
Had it sat for a while?
Does it have a pump in the tank, or is it the external version?
Did you clean the pump housing, or just put in a new pump?
Did you clean the injectors or replace the filters in them?
The PC can indeed go bad and cause gremlins, but a strained fuel system from restricted flow will also blow the fuse, like Kiwi said above.
 
Bike did sit for a while, I replaced the fuel pump and cleaned the housing as best I could. It’s an internal fuel pump inside the tank. I did clean the injectors but not the filters in them, had them sprayed clean.
If it is a strained fuel system I’m thinking the pump or filter. Both are new but it’s possible they arent doing a good job
 
MadAtThisBusa said:
Bike did sit for a while, I replaced the fuel pump and cleaned the housing as best I could. It’s an internal fuel pump inside the tank. I did clean the injectors but not the filters in them, had them sprayed clean.
If it is a strained fuel system I’m thinking the pump or filter. Both are new but it’s possible they arent doing a good job
Click to expand...

Have you done a fuel pressure test?
 
MadAtThisBusa said:
Fuel pump motor having an internal short or fuel filter are where my mind went until yesterday.
Took it out to give it some throttle and test if the fuse really blows at full throttle and it did. Came back and this was my process -

1) Remove 10A Fuel Fuse
2) Tried a 15A and 20A Fuse
3) Turn Key and Ignition Switch
4) Immediately blew both

So I disconnected the PC5, messed with the ground a little bit, installed another 10A fuse for fuel, and it started right up. Made it home with no blown fuse but haven’t ripped on it yet. Is it possible the PC5 is causing my Fuel Fuse to Blow? Maybe my ground is messing up?
Click to expand...
Looks likely that the PC5 is causing this issue, dunno how but maybe it is…. Let us know if disconnectin the PC5 fixes the problem.
 
Disconnected the PC5, cleaned off my grounds, and replaced the 10A fuel fuse with a 15A fuel fuse.
I don’t know what exactly it was but that combination fixed it all up.

Took it on a rip today, went 8-9k rpm in all gears, full throttle, rolled on throttle, it ran absolutely beautiful. I’m thinking all 3 of those things were probably causing a problem but if it happens again I’ll start posting again. Bike is for sale finally
 
MadAtThisBusa said:
Disconnected the PC5, cleaned off my grounds, and replaced the 10A fuel fuse with a 15A fuel fuse.
I don’t know what exactly it was but that combination fixed it all up.

Took it on a rip today, went 8-9k rpm in all gears, full throttle, rolled on throttle, it ran absolutely beautiful. I’m thinking all 3 of those things were probably causing a problem but if it happens again I’ll start posting again. Bike is for sale finally
Click to expand...
Yeah, general rule of fault diagnosis is to only make one change at a time. . If you really want to know where the fault lay.
But it’s great that the issue is sorted and she’s running like a box of fluffy ducks!
Other thing is. . Not all fuses are created equal in quality.
For instance a 15 amp fuse from china at the lowest price available may only get to 12 amps before blowing.
But a German made Bosch fuse of the highest quality will consistently carry 15 amps before it blows.
So the moral of the story is to always use high quality Fuses in every fuse location.
 
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