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Strange engine/fuel behavior
#1
Hi all,

I have a puzzle for you today. A couple days ago my 2007 yzf600r started acting like it was out of gas on the turnpike, even though my low fuel light wasn't on. I was able to restart it and ride for a while, until it happened again. I couldn't restart it this time, but I found out that cycling the key (off and on) allowed me to start it again. I got it to the next exit this way, having to restart it more and more frequently.

I managed to get it back to home where I could work on it through quite an adventure, and found some more symptoms. It seemingly will idle perfectly and for as long as I ask it to, but as soon as I rev it above 5k or 6k it will rev up, then die and stop running. Then it will only restart after a key cycle. It seemed like a clear fuel issue, and I thought I couldn't feel my fuel pump running, so I bought a new one (external style) and installed it with little trouble. This did not fix the issue. It still dies after revving above some certain number. Spark plugs are relatively new, it's getting air, and fuel will run all the way to the carbuerators. Until recently the bike was running perfectly fine and not bogging in any sort of way, so I'm doubting (hoping) that the carbs couldn't possibly get gummed up or clogged that quickly. I made a 3 hour trip like two days before this issue presented itself, and over 1k miles in the past month - there's no way carb issues would manifest that quickly.

If y'all have had similar experiences please let me know and advise how I can possibly fix it. I attached a video that I took that should hopefully show the issues in question, as well as a picture of the fuel pump relay, which appears to be fine (I can feel and hear the fuel pump clicking).

Thank you!!



Attached Files Image(s)
   
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#2
my initial thought was fuel pump too. id be tempted to run a hose from the pump to a gas can and cycle it so i could see the fuel flow to be certain the replacement is moving fuel.

it probably is but id want to be certain. the idle fine die above 5/6k is classic pump not working signs. do you have an inline fuel filter? clogged up? replace that?

i dont have the hard answer but i would want to see the fuel flow myself before going further.
I have a full engines worth of bolts and hardware. if you are missing somthing specialty hit me up I will share.
Goodbye Ashwin, stay safe on the otherside.
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A monkey can memorize facts, but ask one to rebuild a set of forks.....
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I have carb parts.  viewtopic.php?f=23&t=67234
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#3
I think fuel filter. Clean or replace.
I believe it will run without the punp if the fuel level in the tank is high enough.
Also,check for any possible line kinks when you lower the tank into position.
Member: 100,000+ Mile Club (2003 YZF600RR)
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#4
Thanks for the replies folks, after much waiting for parts and troubleshooting I'm about at the same place. This video explains and shows what's happening. This is happening after installing a brand new fuel pump, brand new fuel filter, making sure there are zero kinks in my lines between the tank and the carbs, and seeing that the fuel pump is pushing fuel out of itself. Any suggestions?
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#5
cycle the key and then it can start? (sorry i missed that part in the beginning, but saw in your video) so we got electrical problems. CDI, Coils come to mind but thats just an educated guess
I have a full engines worth of bolts and hardware. if you are missing somthing specialty hit me up I will share.
Goodbye Ashwin, stay safe on the otherside.
YOSHIMURA Club  member #1 President
My technical mentors; Bpro, 893cv.
A monkey can memorize facts, but ask one to rebuild a set of forks.....
-Bpro
"I know what I'm doing is right, I just did it wrong."

2nd Gear Rebuild Vids Here: http://www.youtube.com/user/vashtsdayto ... sults_main

Fork Rebuild: https://youtu.be/7sgxwyaRDO8

I have carb parts.  viewtopic.php?f=23&t=67234
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#6
(06-23-2024, 09:14 PM)vashtsdaytona Wrote: cycle the key and then it can start?  (sorry i missed that part in the beginning, but saw in your video) so we got electrical problems.  CDI, Coils come to mind but thats just an educated guess

That's a good point. I did notice my ignition (where ya put the key in) is a little looser recently, it'll like jiggle around in its mount. Maybe a loose wire in there? The other thing I was thinking is maybe one of my coil packs went bad so I'm running one or two cylinders down. That might explain the seemingly stable idle but death once it gets any meaningful RPM. Also noticed that the bike might sound different, hard to tell. Any ideas on where to start troubleshooting? I'm familiar with a multimeter.
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#7
I'm with Vash. 
You've ruled out fuel and ignition.  I don't think it is a coil heating up, because there are two of them; it wouldn't just die.
Cycling the key is like restarting a computer, so I'm going to assume that that is what you are doing; you are resetting the "brain".
I would normally say to check the ground cable at the engine case, but the thing is cranking over like a champ.  No problem with battery power.
I have never seen nor heard of this particular problem on a YZF, but my guess is the "brain".  A quick eBay search turned up a bunch of them.  From around $75 on up.  One $100 listing said "Guaranteed".

This is from Revzilla.  I looked up the 2007 model, but I'm pretty sure all years are the same from '97 - 2007
IGNITOR UNIT ASSY
4TV-82305-50-00

   
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#8
I think eliminating the main switch as a culprit would be a good start.  Extra current for the coils at high revs might be the cause if the switch contacts aren't up to par.  Then a reset restores the connection til you ask for higher current again.
You haven't mentioned the headlight or other electrical dying along with the ignition, so that seems to narrow it down to the 2 blue wires in the image.
You can either:
a) make it die, then measure resistance from 3 to 4 before you touch the switch
b) jumper connections 3 to 4 of switch, and see if problem is 'fixed'.

   
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#9
Hmmm...

[Image: 2pzj16-1024x614.jpg]
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#10
(06-24-2024, 02:09 PM)tuning-forks Wrote: I think eliminating the main switch as a culprit would be a good start. 
Welp, I did some testing and came up with some interesting results to say the least. To begin with, I checked the main switch how my Haynes manual suggested and got an open loop on all four pins of the connector.
     
I also found that it's definitely an electrical issue, most likely current supply, by looking at the headlight. I've been testing during the day and it initially broke before dusk, so I haven't noticed so far. It looks like my low beam will turn on just fine but a high beam (presumably drawing more current) flickers on and off rapidly. Hopefully that shows in the video.

As to the source of the problem, I don't think it's the main switch itself. It is still kind of loose in its housing, but it's a closed system so I wasn't able to test for continuity. On the other hand, I was able to use the wiring diagram to trace the wires on the other side back to their sources. Here's the interesting part. I found zero continuity between the red wire and the battery, where it should lead to, and the same for the relay of the blue and yellow wire. This is with the key in any position, although it's unplugged so I don't think it really matters - but I can't have it plugged in and testing the pins, obviously.  Here's a picture of my result for the blue and yellow wire from the main switch connector to the relay, and some proof that my multimeter is working properly.
       
Now, what puzzles me is: how is the bike getting anything through the main switch if there's a completely open loop on all pins of that connector?    
Just for sanity's sake, I did check and my battery's giving a healthy 12.4v between the posts; but between the power pin for the main switch and either battery terminal I get no resistance, indicating a break somewhere. I'll put some photos of where you can see the wire bundle between the relay/battery and the pins, highlighted on or under. Please tell me if anything at all looks like a broken circuit or anything that's off at all.
           
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#11
Referring back to what Tuning Forks posted, it shows testing at the connector that comes from the main switch.
First of all, be sure that the switch is in the ON position.
Then check for continuity between red and brown/blue (1 and 2 in the diagram) at that connector only.
Next, check for continuity between blue/black and blue/yellow (3 and 4 in the diagram.)

Don't check between the two connectors like it appears you are doing in your photo.
Member: 100,000+ Mile Club (2003 YZF600RR)
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#12
(06-27-2024, 02:28 PM)Reserector Wrote: Referring back to what Tuning Forks posted, it shows testing at the connector that comes from the main switch.
First of all, be sure that the switch is in the ON position.
Then check for continuity between red and brown/blue (1 and 2 in the diagram) at that connector only.
Next, check for continuity between blue/black and blue/yellow (3 and 4 in the diagram.)

Don't check between the two connectors like it appears you are doing in your photo.

Shit, my fault, I misinterpreted. I think this may be the culprit though. All prongs look clean, and there's a healthy connection between red and brown, but blue and blue striped are intermittently connected and not. Note that I tested both ends, the video is the bike end and the pictures are the ignition end. While the bike end is intermittently connected, the ignition side for blues had a brief spurt of resistance and then went down and stayed at open loop. Not sure why this would cause the symptoms it has but I don't think it's right. Would anyone be able to test a known functioning main switch and see if the same happens? Video attached. (OL is open loop = no connectivity, 0.00 means connected. Sorry about the Geiger counter audio, autofocus ruined from riding w/ phone).
Also note that after I tested, the bike got way harder to start. As in, it barely did at all when I plugged the switch back in. Hopefully all is well. ?

Bike end:


Main switch end:
       
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#13
The switch is the only thing that test is good for. If one of your connections is hit and miss, the switch may be the problem.

If you can make two jumper wires to take the place of the switch by jumping the connections on the bike end connector, you should be able to start and rev the bike no problem. That would prove it is the switch going bad.
Member: 100,000+ Mile Club (2003 YZF600RR)
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#14
(06-28-2024, 07:04 AM)Reserector Wrote: The switch is the only thing that test is good for.  If one of your connections is hit and miss, the switch may be the problem. 

If you can make two jumper wires to take the place of the switch by jumping the connections on the bike end connector, you should be able to start and rev the bike no problem.  That would prove it is the switch going bad.

Looks like it's not the switch then. I was able to make two jumpers and all electricals came on no prob, but the bike just wouldn't start. I was able to bump-start it, but it was even reluctant to do that - took one or two turns of the engine to go on its own power. It was definitely a bit sluggish, I'm not sure what a misfire/running on 3 sounds and feels like but it definitely could have been. That's what makes me think it could be a coil or something.
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#15
But I thought it was running well up to a certain RPM...
Maybe recheck any connectors that you have disturbed during the investigation so far.
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#16
The 2 blues at the key switch side connector must stay at zero ohms when switch turned on.
If not, you have likely found your issue.
As Reserector stated, you can add a jumper between the 2 blues. This might be able to be done by jamming in a jumper wire 'back-side' of the connector so you can reconnect the 2 sides so the rest of the switch works. By back side I mean where the wires come out of the bike side connector. Usually you can jam wires in there to make a connection. Needs to fit snug.
If the jumper cures the problem, you can add a hidden security 'kill' switch if you don't want to replace the main switch.
This would require snipping the blues at the bike end connector, and running them to a hidden toggle switch.

Never mind, I missed the updates.
But it's possible you now have more than one issue to deal with, so I'll leave that switch info there.
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#17
What did you figure out? Is it fixed?
Member: 100,000+ Mile Club (2003 YZF600RR)
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#18
(07-10-2024, 12:20 PM)Reserector Wrote: What did you figure out?  Is it fixed?

It is not. I charged the battery and replaced the regulator/rectifier, which showed all signs of being the issue, but unfortunately no dice. A new ignition is coming in the next couple days, so I'll replace that and see if it works. I believe a bad R/R may have overvolted other components, maybe causing myriad electrical issues.
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#19
Mine went bad and produced high(er) voltage, but never cooked anything. Well, maybe the battery.
Tight, clean connections are paramount to success when it comes to the reg/rect. If they are loose or dirty they will burn up. Silicone dielectric grease is a good thing to slather on them as well.
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