Fast Idle and WOT Bogged Down

[Dracken]

Hi Guys,

As the title indicates, I'm having trouble with my 2006 Busa. The bike is idling at a higher speed, around 1500-1600 RPM, than the 1250 it used to and when throttle is wide open or nearly wot (> 75%) the bike bogs down. I have only a few mods that would affect the engine: Power Commander 5, GiPro ATRE w/ Gear Display and a K&N Air Filter. Attached is a screen capture of the Power Commander Control Center w/ fuel mapping at idle, the bike had been ridden and was warm and the choke was closed when this was captured. There's no visibly extra smoke from the tailpipe and fuel economy is averaging around 40 mpg city/highway combined. Bike has about 48,000 miles on the odometer. I was thinking that there may be an issue with a fuel pressure regulator or a stuck open fuel injector, would tools to test this be available at an autoparts store for rent/loan or would only a dealer/mechanic have those tools? Any other ideas as what could be the cause? Between this and 2nd gear slipping under load (yeah, that known issue that Suzuki won't recall) I'm getting frustrated.

Thanks!

Dracken

 

[Dracken]

Oy, almost 75 views and no replies? I've tried running seafoam with no luck. Could the problem be a clogged fuel filter and the fuel regulator is trying to compensate? If the fuel regulator is going, is it part of the fuel pump assembly? I've tried looking for it in schematics (like on bikebandit) as well as a place that has oem (again, bb) with no results. I'm a diy'er and like to learn more about my bike by working on it, but a little guidance is appreciated. I did try searching (I find it hard to believe that I'm the only one that has had this problem) and skimming posts came away empty handed, seems the keywords are too short and come with to many results.

Thanks!

 

[dadofthree]

PM gixerhp

 

[Dracken]

Cool, will do, thanks. Btw, I have family in Barnwell...small world :-)

 

[GIXERHP]

Is this bike tuned on a Dyno??
What map is loaded?
What exhaust?

 

[Dracken]

Not dyno'd, stock exhaust and default tune in the PC5.

 

[Zoro]

Crap in the fuel pump screens, need to remove pump and internal filters..

 

[GIXERHP]

Disconnect the PC and see if the problem goes away

 

[dadofthree]

Cool, will do, thanks. Btw, I have family in Barnwell...small world :-)

drop their name because everyone knows everyone

 

[Dracken]

drop their name because everyone knows everyone

Hah, nice... PM sent

 

[dadofthree]

PM returned

 

[Dracken]

Disconnect the PC and see if the problem goes away

I disconnected both the PC5 and the aTRE with the same results.

Crap in the fuel pump screens, need to remove pump and internal filters..

I have a repair manual for the Gen 1 Busa, section 4-52 (page 234) seems to have some directions on how to remove the fuel pump assembly. I've not removed the tank, so hopefully it's a fairly straight forward task.

Doing more searching, I found this thread https://www.hayabusa.org/forum/busa-problems/119782-04-stumbling-@-6-000-rpm.html that had a similar issue with a similar bike having throttle issues in high rpm's as well, turned out to be the fuel pump. I hope that's not the problem and is just a simple clog. I'll try to tear into the bike this weekend.

Thanks again for the suggestions.

 

[E Zurcher]

Fuel filter, 06s have the regulator as part of the filter. You may have gotten some bad gas or it's just clogged. The filter medium is surprising ly small and very fine so it clogs easily. Usually the first sign is you can hear the pump whining while the motor is running as it strains to push fuel through the filter. Also if you give it WOT and then back off slightly, and the motor speeds up a bit is also a symptom.

Be prepared, the filter is expensive and you have to disassemble the pump from the filter to change it once you get the whole sender, fuel pump and filter out.

Do a search on fuel filters and you will find a lot of info. Oh and don't bother trying to backflush it because it will only last a couple hundred miles at most and you will be back where you were.

Once you replace it you will be surprised at the performance you regain.

Good luck.

 

[Dracken]

Fuel filter, 06s have the regulator as part of the filter. You may have gotten some bad gas or it's just clogged. The filter medium is surprising ly small and very fine so it clogs easily. Usually the first sign is you can hear the pump whining while the motor is running as it strains to push fuel through the filter. Also if you give it WOT and then back off slightly, and the motor speeds up a bit is also a symptom.

Be prepared, the filter is expensive and you have to disassemble the pump from the filter to change it once you get the whole sender, fuel pump and filter out.

Do a search on fuel filters and you will find a lot of info. Oh and don't bother trying to backflush it because it will only last a couple hundred miles at most and you will be back where you were.

Once you replace it you will be surprised at the performance you regain.

Good luck.

I was going to try to get into the bike this weekend, but we're getting about 6 inches of snow tonight and I have at least half a tank of fuel which I was planning on riding to get the fuel down... that might have to happen later in the week. I was looking at fuel filter prices, looks like just shy of $300 (which is nuts). I'll probably flush it out to confirm if it is that, and then replace if the results are positive.

Thanks for the heads up.

 

[MC MUSTANG]

Sounds like the fuel filter/pump to me. Any chance of trying out a used/reconditioned one just to see if it makes a difference? If you are going to have to take it apart anyway...

 

[Dracken]

Sounds like the fuel filter/pump to me. Any chance of trying out a used/reconditioned one just to see if it makes a difference? If you are going to have to take it apart anyway...

Since a new filter is ~$300 and a new pump even more at around $700 for the entire assembly or a fuel strainer at around $60, I figured I'd try to test them first before committing to a pricy solution that doesn't rectify the problem. I suspect looking for a reconditioned pump is precarious at best although I do see a few on eBay for cheap, so if the issue isn't resolved by back flushing the filter and screen, I'll guess try a reconditioned and hope that it works.

Thanks!

 

[E Zurcher]

Your pump is probably just fine they don't go bad very often and when they fail they usually just quit working. If you get the filter, which should be around 240 bucks through Honda East, and that's not the problem at least you'll have a spare. If you put miles on your bike, you will need to replace it eventually. There is also a mod on this forum which allows you to bypass the internal filter and use an external automotive filter. I replaced my internal with a new one and my bike was restored. My buddy replaced his on his 06 and he was amazed at the difference. IMO it should be done every 15-20k anyway. There is very little filter medium in the filter to begin with.

 

[Dracken]

Quick update. Finally got to tearing into the bike and found this... gunk all in the strainer. I removed and sprayed out the strainer with some carb cleaner and it made an improvement, but there is obviously something else wrong as the bike is still having the same issues.

I looked at this how-to for the 2001-2007 fuel pump mod (https://www.hayabusa.org/forum/maintenance-do-yourself/175027-fuel-filter-mod.html) which came in handy, and may be how I'm going to go for the future instead of replacing an overpriced fuel filter from the dealer.

 

[ProvorseD]

I had a serious problem with my Busa when I got it. It was bogging down badly just like your describing. I found my problem when I pulled out the injectors and saw that they had rust on the face of them. I looked into how to clean injectors. I decided to spray them out as best as possible from both directions using brake cleaner. I also used a soft toothbrush to scrub the face of them. I then sent the injectors to a professional to have them cleaned. When they came back with a report it showed that the injectors sprayed perfectly before and after the 'professional' cleaning.

My suggestion, pull your injectors out and spray the hell out of them with brake cleaner. Put it back together and see if that doesn't solve your bogging down issue.

I didn't experience any high idle issues so I want to suspect that the source is something else. - Best of luck to you.

 

[Dracken]

Got a new fuel filter in the mail today and installed it as soon as I could, took care of the problem, bike is pulling hard again! Thank you to all that called the fuel filter as the culprit.