MY 907 SPUTTERS AND STOPS AFTER 15 OR 20 MINUTES!

[slopaso]

HELP!

I have a beautiful customized 907 with 26,000 miles that has a gremlin. it starts up and will run the first 15 or 20 minutes as if off the showroom floor. but then its starts sputtering and hesitating as if running out of gas (it isn't ) and then leaves me stranded.

HELP!

We have changed the fuel filter several times, that's not it.

We saw some rust on the tank inner lining so we drained and coated with rubber liquid liner, that's no tit.

We re-drained the tank and poured the cleaner through the hard pipe section of the fuel line and gobs of the goop did come out (it had gotten past the plug), but that's not it eather.

HELP!

We feel like we have followed all fuel delivery possiblities and doesn't seem to be the problem. At a party, someone told me his friend had a similar problem on a Honda and it turned out to be electrical. He mentioned something about an ICBM box but by the time i got my mechanic/roomate over, i couldn't find the guy again.

HELP!

Can anyone offer any suggestions. I love this bike and had a 750 PASO for 11 years before trading up to the 907. I don't want to give up on it but i am at a standstill........

[persempre907]

I had a similar issue on my old 906 and turned out the pick up on the flywheel was broken.
Good luck .
Ciao

[jcslocum]

When it quits runnubg, does the fuel pump still run?

Do you have spark when it quits?? Grab an extra spark plug and once it quits, pull one plug wire and plug it onto the extra plug. Ground the plug against the engine and give it a crank. You should see a nice blue spark jump the gap. It easiest to do this in the shade or at night so you can really see the spark.

[ducinthebay]

Two strong possibilities;
1. Coils are dying. After they heat up, they start to short internally. they will check out fine when cool. Check the spark when it dies, as was suggested. If you still have stock coils, you may need new ones, as coils are a replaceable item.

2. the vent tube is blocked. After 15-20 minutes of riding you create enough vacuum to overcome the fuel pump. Easy way to check is is ride with the fuel cap a bit loose to avoid creating a vacuum in your tank.

Cheers,

[slopaso]

Thanks to all for suggestions. Here is an update. We thought we had a loose fuel line inside the tank and re-attached it. I got stranded again but this time I have a little more info

The bike ran for about 1 hour and then started hesitating. About once every couple minutes. Finally it started dying on me. AS I rev'ed it to keep it going, the people behind me said they saw BLACK SMOKE COMING FROM THE RIGHT PIPE (RICH) AND THE LEFT PIPE WAS POPPING (LEAN)

THis was probably happening the last times but since I was behind my friends, no one saw it. Does that information give any help in figuring out what is wrong? As usual, after I trailer the bike home and it sits for a couple days, it starts up again as if nothing is wrong. Just enough to give a false sense of security and lure me out on to the roads just to strand me again.

Soemthing else that might matter. THe temp guage doesn't work, but the bike doesn not overheat. I was told by a dealer that there are two or three temp sensors in the bike and that one or two of them don't work ( I don't remember it waws years ago- this bike has sat in garage more than it has run in the last three years).

ANy ideas?

[ducapaso]

The smoke comes out of the mufflers or from where?
Don't you have the 2in2 cross pipe?

[paso750]

I was told by a dealer that there are two or three temp sensors in the bike and that one or two of them don't work

why don`t you change them ? It sounds as if the problem occurs when the engine gets warm.

G.

[englishstiv]

Check the wires and connections under and to the the fuel tank and also the connection bloke onto the the main loom. I had a similiar issue that was down to loose and corroded connections here.

[Laddie907]

first up...

Temperature sensors.
the bike has a water temp and an air temp sensor that send signals to the ECU.
the air temp sensor is on the air box.
the temp guage on the dash is run from a separate water sensor located on the tube behind the radiator.

I wrote a post on testing the sensors a while back; they can be tested with hot water and a multimeter.
The sensors do fail - but the failure mode should not cause the problems you describe.

[Laddie907]

secondly

I have experienced the "bad" misfire and black smoke...
It had run perfectly for an hour before; another member here (Jaffa) saw the smoke...the bike was misfiring badly and played up ...but it was intermittant.
The bike played up for about 15 minutes... then ran perfectly for an hour after same day...go figure!!!

I pulled off the main plug to the ECU and hit it with WD40; this worked - but I'd recommend using the correct electrical grease to maintain clean contacts.

You might also check flow at the regulator...these have been known to seize; but unlikely if the bike runs well otherwise....

[Laddie907]

and finally...

the ciggie butt trick...there is a post at this forum related to this...

Some 907's develop a hesitation at cruise after they heat up.
The bike ran like a charm up to operating temp - then went haywire...intermittantly, but consistant enough to be a problem.

Obviously not all bikes have this problem - but many are quite extensively modified in the air box department, too.
My bike is alsost "stock" with the exception of pipes..and a suited FIM chip. (It still misfired)
misfire has been observed on a diagnosis computor; the firing timing intermittantly went all over the place...it was never pinned down to a particular faulty component BUT a cigarette butt in the MAP sensor air line made it go away.

Some other members here have said it worked for them...it can't hurt to try...

[Laddie907]

and one more thing...the filters...

I've been conned with the filter change thing a few times...
the filters are very rarely the cause of a fuel problem; if the fuel flows it's NOT the filter.
The fuel still flows and maintains 3 bar pressure even if the filter is full of crap choked solid.

sure, change them if you're concerned that you'll block the injectors - but that's never happened to me...
any junk in the fuel line after the injector is usually the fuel line decomposing.

[higgy]

I got a bone to pick here, laddieboy filters routinely are still the issue in any fuel system.While they are certainly not the only issue, they are by far the most common issue and the cheapest and easiest component of any fuel system to replace and they are often neglected by even the most savvy techs. Pressure is no way to tell the status of your filter you must measure the flow,once again you must measure the flow and make sure it is clear of water or any other contaminant. Just a word to the wise,take nothing for granted. Filters are responsible for 90% of all fuel system failures period!!!! Only a fool would replace any fuel system component without also replacing the filter, it is simply chaep inisurance and always a good idea. Rant off

[du907]

Check the main plug into the ECU under the seat, right side to make sure it is not loose. It happened to me, I found it after about 3 days of trouble shooting. The plug has a hook on one side and the ECU has a metal clip that holds on to a tab on the the other side of the plug. I use a zip tie to make sure it never unplugs again.

So we have to try and look at things that change after it warms up. Temp. sensors as mentioned would be a good start. Use a Ohm meter to check them. Something expands as it warms up and messes up the fuel injection and or timing. I would check the air gap at the pick ups that read the fly wheel. Does wet or moisture make any difference? Does your coolant hose swell and rub against the the throttle bodies on the left side? I would check the coils as already mentioned too. On the left side, just under the tank toward the rear of the tank and strapped to the frame, there are two amp spring electrical connectors that can deteriorate and if disconnected will stop the engine (I think one is white plastic). Remove the left side cover and check the main fuse block on the left side for a weak filament (not the little fuse block under the seat with multiple blade fuses). The only other thing I can think of is something that goes ground when the bike warms up. Wait a minute! I remember one track day after the winter my battery was weak. The bike would push start cold and spit and sputter but would run until it warmed up. It turn out to be the battery. Anyway, after replacing the battery with one I got at the local Western Auto; the battery didn't come fully charged; I went out on the track and the bike spit and sputtered and black smoke and backfiring until the battery charged up after lap after lap. My point being that your battery may be good, but you still don't have enough volts or amps to run the fuel injection and all the other electronics after it warms up. Next time you run it and it acts up, check the voltage and see if it is up enough. If not, it could be in the alternator, regulator, the wires associated with these, and check the connectors at the steering head just down line from the regulator and see if they are hot to the touch. If so, first clean them of rust, if the wires don't cool down, replace the connectors with something the same size. Just trying to give you some suggestions and places to look.

Good luck and keep us informed.
du907

[davo]

Hi Slopaso, my Duck did the exact same thing when my regulator died. If you ride the bike when the battery isn`t being re-charged or the voltage falls bellow the recommended level, mis-firing will occur.

It`s just a thought, maybe check the battery voltage when the bike starts to play up. It should be around 13.5 to 14v with a healthy charging system.

Good luck!