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TECHNICAL => HELP! => Topic started by: TECH on June 17, 2017, 07:41:05 PM

Title: Stumbling, Bumbling, Bogging 2004 'Busa
Post by: TECH on June 17, 2017, 07:41:05 PM
Hi folks!  Long time no post!  I've been out of the riding scene for years, and browsing my old posts brings back a lot of memories.   :tu:

Anyway, there is a 2004 'Busa in my shop that was traded in, and a co-worker wants to buy it.  First we had to put fuel in it, as it was out of gas and wouldn't start.  I took it for a spin and it bogs really bad, sputters, jerks, and it never really put out any power even if it seemed to smooth out at higher rpm.  At a stop in neutral, you can open the throttle at any opening and it'll sputter and bog, no throttle response.  Open wot and it'll bog and eventually snap to higher rpm.

The bike is stock with 20k miles except for a k&n filter as far as I can tell, even has the stock airbox flapper.  I pulled the plugs and they look decent, but very white, which makes me believe it's getting little fuel.  All 4 exhaust pipes are heating up.  No FI light is on.  I have not tried to pull codes.  What I did find that seems to help, is unplug the vacuum line from the MAP sensor.  'Course it doesn't want to idle then, but it'll throttle up and rev, and make my d*ck hard (...memories...) with that line off.  That should make it run richer in that state, and it runs much better.  I installed a different MAP from my old parts, and it didn't help.
 
Any suggestions on what to try next?  I have limited time to punk around with it, unless I want to stay late at work.  I'm suspecting a weak fuel pump, something clogged in the fuel system or a wonky sensor.  I'll probably check the TPS (throttle sensor), and end up checking the fuel system.   

Thanks!
Title: Re: Stumbling, Bumbling, Bogging 2004 'Busa
Post by: RansomT on June 17, 2017, 10:20:02 PM
Check Fuel Pressure .... bet it's a bad fuel pump. 
Title: Re: Stumbling, Bumbling, Bogging 2004 'Busa
Post by: STUNNAH on June 18, 2017, 03:43:58 AM
Before I chased too many gremlins I would put a set of plugs in...
Title: Re: Stumbling, Bumbling, Bogging 2004 'Busa
Post by: sportbikeryder on June 18, 2017, 09:26:33 AM
Prob not a bad idea to pull the injectors and send them to Scott Horner to be cleaned. I'd also pull the pump from the taking also look it over, especially the sock /screen on the inlet. While it is also dart you can try to spray some cleaner in the filter (large black housing).
Title: Re: Stumbling, Bumbling, Bogging 2004 'Busa
Post by: HOS on June 18, 2017, 01:34:30 PM
Check the fuel lines under the tank., make sure no kinks in them.
Common problem.
Title: Re: Stumbling, Bumbling, Bogging 2004 'Busa
Post by: TECH on July 02, 2017, 12:56:11 PM
I checked the fuel pressure, but only the pressure when the pump is primed when the key is turned on, not running.  ~23 psi.  I understand the pressure should be about ~42 psi, but is that only while running, or should it prime that high also?

I ended up buying the bike, as my co-worker got cold feet/wife veto...  $2400 and change out the door.   :tu:
Title: Re: Stumbling, Bumbling, Bogging 2004 'Busa
Post by: RansomT on July 02, 2017, 02:07:38 PM
Unless the battery is crazy weak, it should prime to 42 psi.

Speaking of batteries, crazy things also happens if the battery is very weak.  I've seen all kinds of anomalous things happen when folks jump a Suzuki to start it with a nearly dead battery.
Title: Re: Stumbling, Bumbling, Bogging 2004 'Busa
Post by: TT on July 13, 2017, 07:37:09 AM
Prob not a bad idea to pull the injectors and send them to Scott Horner to be cleaned. I'd also pull the pump from the taking also look it over, especially the sock /screen on the inlet. While it is also dart you can try to spray some cleaner in the filter (large black housing).
yep what ^^ he said,  u said the plugs were white (lean )  and u said u had to put gas in it    i wonder how long it sat empty with just fuel sitting in the injectors plugging them up
Title: Re: Stumbling, Bumbling, Bogging 2004 'Busa
Post by: TECH on April 21, 2020, 11:48:57 AM
Guess I'll post what I found after all this time.  The fuel pump took a  :toilet: :poop:  Not wanting to spend $600 bucks on a new factory pump, I dug up some info on the web about a car pump (edit: $100) that was an equivalent replacement which only needed to be cracked from it's plastic housing, and I modded the wiring to work.  Runs perfect.  The bike has sat in my garage for a couple years and I only rode it a few times.  Needs a battery now and I plan to sell it.  I have plans to build a big garage shop on my property and I have too many things sitting unused.