Engine Cuts Out & Runs Rough

J

JonnyQuest264

Registered
Hey all,
Working on a police buddy’s Gen 2 (2009) with 10k miles. It would cut out and run very poorly at low rpm & barely start, also higher rpm’s would cut out and not maintain rpm.

I went ahead and replaced the fuel pump & filter, replaced the plugs, and made sure the air filter was clean.
It does have a power commander, K&N air filter, and Two Bros slip-ons.
After patching everything back up, started it up and ran like a gem! Though all was right with the world.
Later took it out for a good run and after 10 minutes it started running like garbage, rpm’s cutting out, and felt like it would barely make it home.

Can anyone point me in the right direction?

If all else fails it’s off to the dealership service department to get bent over.

Thanks!
 
Hayabusa Wannabe said:
Welcome to the forum @JonnyQuest264.

Is the tank clean? Did you perform any cleaning such as the tank or injector screens the first time?

Fuel controllers can fail from the heat as they are not built to the automotive spec like the ECU. Try disabling the Power Commander.

The fuel pump - OEM or aftermarket? Some aftermarket ones do not meet the fuel delivery spec.
Click to expand...
Thanks!
Tank is very clean looking on the inside, took a bore scope to it.
Not sure where the injector screens are located?

I wondered if the fuel controller piggyback (power commander) is failing, thought about disconnecting it but a little bit of a chore.
 
JonnyQuest264 said:
Hey all,
Working on a police buddy’s Gen 2 (2009) with 10k miles. It would cut out and run very poorly at low rpm & barely start, also higher rpm’s would cut out and not maintain rpm.

I went ahead and replaced the fuel pump & filter, replaced the plugs, and made sure the air filter was clean.
It does have a power commander, K&N air filter, and Two Bros slip-ons.
After patching everything back up, started it up and ran like a gem! Though all was right with the world.
Later took it out for a good run and after 10 minutes it started running like garbage, rpm’s cutting out, and felt like it would barely make it home.

Can anyone point me in the right direction?

If all else fails it’s off to the dealership service department to get bent over.

Thanks!
Click to expand...
Hi bro,

Welcome to the busa family.

There is a mesh filter in the regulator, you can test if that strainer problem by removing the pump and regulator and seperated the regulator from the regulator housing.

Use a carb cleaner and sponge (to ensure the pressure go 1 way) and do a back purge, let the carb cleaner come out from the regulator or pump

After a half can of carb cleaner. Re assemble back. And the bike can perform normally for the next 20miles. The regulator strainer is the problem.

If confirm the regulator is the problem. Do not throw away ur old pump. Buy a China Fuel Pump and dismantle. Keep only the filter. If purchase seperately the filter is like $300+ use the China filter is like $70. Do it quick before the tariff kick in!
 
JonnyQuest264 said:
Hey all,
Working on a police buddy’s Gen 2 (2009) with 10k miles. It would cut out and run very poorly at low rpm & barely start, also higher rpm’s would cut out and not maintain rpm.

I went ahead and replaced the fuel pump & filter, replaced the plugs, and made sure the air filter was clean.
It does have a power commander, K&N air filter, and Two Bros slip-ons.
After patching everything back up, started it up and ran like a gem! Though all was right with the world.
Later took it out for a good run and after 10 minutes it started running like garbage, rpm’s cutting out, and felt like it would barely make it home.

Can anyone point me in the right direction?

If all else fails it’s off to the dealership service department to get bent over.

Thanks!
Click to expand...
I echo the words @Hayabusa Wannabe said and take the power commander off to try that first.......

I had an issue with my bike a couple summers ago and the first thing that came to mind was to remove my Bazzaz system......the bike ran perfectly without it.....

Go after the lowest hanging fruit first and work your way out from there.....
 
Dafeimao85 said:
Hi bro,

Welcome to the busa family.

There is a mesh filter in the regulator, you can test if that strainer problem by removing the pump and regulator and seperated the regulator from the regulator housing.

Use a carb cleaner and sponge (to ensure the pressure go 1 way) and do a back purge, let the carb cleaner come out from the regulator or pump

After a half can of carb cleaner. Re assemble back. And the bike can perform normally for the next 20miles. The regulator strainer is the problem.

If confirm the regulator is the problem. Do not throw away ur old pump. Buy a China Fuel Pump and dismantle. Keep only the filter. If purchase seperately the filter is like $300+ use the China filter is like $70. Do it quick before the tariff kick in!
Click to expand...
Are you talking about this part? If so how do I get to the mesh?
Thanks!

IMG_2503.webp
 
JonnyQuest264 said:
Are you talking about this part? If so how do I get to the mesh?
Thanks!

View attachment 1695909
Click to expand...
Yes the whole white thing + the black cap. There is a mesh strainer inside...

The whole mesh is welded. They design it in a way that you need to replace the whole item.

How to dismantle Gen 2 Fuel Pump

Then like I mention, remb to first remove the pump and regulator before back purge. Don't let the dirt choke up the pump and regulator.

Then get the carb cleaner and use the red stick given and poke thru the sponge and use the sponge to act as a seal and using carb cleaner pressure to back purge the filter out. Do not do the forward purge! Cause more dirt to stuck at the mesh!

1000122755.webp


The discharge connect to the pump holder. Back purge via this hole...

Please please please wear a safety spec, for the glove can just use a plastic bag to act as a glove. The carb cleaner is very corrosive.
 
Do remb to check ur relay for ur fuel pump

The good news is that the fan relay and the fuel pump relay is the same piece of relay.

Just plug out fan relay at the fuse box area on the left and replace the fuel pump relay on the left near rider seat.
 
Dafeimao85 said:
Do remb to check ur relay for ur fuel pump

The good news is that the fan relay and the fuel pump relay is the same piece of relay.

Just plug out fan relay at the fuse box area on the left and replace the fuel pump relay on the left near rider seat.
Click to expand...
The fuel pump works, I can hear it. If it were the relay wouldn’t the bike just not run all, killing power to the fuel pump?
 
JonnyQuest264 said:
The fuel pump works, I can hear it. If it were the relay wouldn’t the bike just not run all, killing power to the fuel pump?
Click to expand...
Happen to my busa.

You must understand that the relay is a electrical equipment using 12v (battery) to regulate the ~70v generated your stator to your fuel pump.

My relay has bad contact. When at higher rpm it just cut off and cut on. Eventually I just switch with fan relay and all works alright until my fuel pump strainer choke...

In anycase the best test is the fuel flow test. I did my fuel flow test with a bad discharge strainer and manage to get 230ml/10sec

Check out the link where I posted "Gen 2.5 Fuel Pump change out"
 
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