| Author |
Message |
    
S3thunder
| | Posted on Saturday, September 09, 2006 - 10:55 pm: | 
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Help, if there are any tube frame buellers out there that have had a problem with intermittent cutting out of the engine I'd like to know what solutions you found. I have an S3 that cuts out when it is cold, even with partial choke on, and I can see the tach drop about 300-400 rpm. It is worst in cold moist air like fog but any cold humid morning will do. When the day warms up the problem goes away. Getting to work is a dicey ride, but going home it's all good. On a hot day the bike is fine right out of the garage where I keep it. So far I have replaced the coil, the plug wires, checked the plugs, put dielectric grease on the main connector plug off the ignition switch and tested the VOES unit to see that it works. I have also replaced the intake and carb seals, taken the carb apart, checked float levels and blown out the jets. Perhaps I should change the carb for a spare that I have? I think this thing is electrical because of the fog as a trigger but it could be a fuel supply problem too. I am out of guesses.
I appreciate any help,
Thanks |
Sparky
| | Posted on Saturday, September 09, 2006 - 11:56 pm: |
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I don't know if this is related, but my 98 S3 will starve for gas when it rains, sometimes. The problem is in the gas tank vent valve. What happens is the vent valve tends to stick and shut when it rains. Eventually this stops the flow of gas to the carb because of a partial vacuum that develops when the tank does not vent properly, resulting in a running-out-of-gas symptom. The fix is to pop open the gas cap allowing air in and resuming normal operation. Then, it doesn't happen any more until the next time it rains. Weird, huh?
So, next time your bike misbehaves like it's been doing, try popping open the gas cap momentarily and see if it clears up. |
Jaybird
| | Posted on Sunday, September 10, 2006 - 08:50 pm: |
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I have an 05 xb12scg w 4900 mi,at 4 to 5k rpm it dies,sometimes it restarts and sometimes i have to wait a while,its under warranty but the dealer is a long way,any thoughts or ideas will sure help,thanks |
Blake
| | Posted on Monday, September 11, 2006 - 01:02 am: |
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Check spark plugs and also check the sidestand safety cutout switch. |
Sparky
| | Posted on Monday, September 11, 2006 - 11:13 am: |
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Jaybird, when it dies, does the tach immediately go to 0 rpms or does it continue to track the rpms as the engine dies?
Knowing this would help pinpoint whether the ignition is losing 12 VDC power or not. If it is, then troubleshooting can look for the cause, like, for instance, a defective side stand switch or other possible interrupters in the ignition ckt. |
Ap_sand
| | Posted on Monday, September 11, 2006 - 06:30 pm: |
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I have a 2002 M2 that I ride year round here in the Puget Sound area. On cold mornings, when encountering fog on the way to work, I get carb ice. |
Jaybird
| | Posted on Friday, September 15, 2006 - 08:50 am: |
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I have not been able to ride again,but i have looked for the sidestand switch,i cant find it,my bike and my wifes cityx will both continue to run in gear,clutch out and moving w/the sidestand down,am i missing something or going crazy?help |
Yellow_in_ky
| | Posted on Wednesday, September 20, 2006 - 10:59 pm: |
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Hey, I've got a 06 xb12ss with the race kit. It Will not pull it's self under 2k when the motor is cold. Then when it dose warm up it hesitates and acts up under 3500 to 4000 rpm. It runs great above 1/2 throttle. The factory has replaced the complete throttle body. Checked and or reset the timing, fuel pressure, and other related parts. Anyone else having these problems? HELP !!!! |
Blake
| | Posted on Thursday, September 21, 2006 - 07:30 am: |
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First, except for during take-off from a stop, don't run the engine under load under 2K rpm.
I seem to recall hearing about some faulty race ECMs not too long ago. You might look to that as the root cause. A proper TPS reset/rezero may also be something to consider.
Might also check for intake manifold seal air leak. Set a warmed-up engine at a fast idle, around 2K rpm and spray electrical contact cleaner all around each seal between cylinder heads and intake manifold and also around throttle body to intake manifold seal. If/when the engine speed changes noticeably, you have identified an intake seal air leak. Be sure to prevent the contact cleaner from entering the intake as you spray. That would produce a false diagnosis.  You can use a fine mist of water or WD-40 in place of contact cleaner. |
S3thunder
| | Posted on Saturday, October 07, 2006 - 07:56 pm: |
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I'm back on this problem after trying all the suggestions and then some. I am two hours at speed away from the nearest shop that will work on my S3 so I pretty much have to figure it out. I don't have a sidestand switch, it was disconnected before I bought the bike. I recently took off the muffler to repair a rattle inside. While I had it off, I started up the engine and found that it didn't show any cutting out on the tach. It did sound a bit off at the midrange but the tach was solid and no jumping around. When I put the muffler, a straight through Two Brothers, back on, the engine went right back to breaking up with the tach jumping around at 3500-4000 with no load (just sitting on the sidestand in the driveway). Does this sound like an air problem? carburetion? mixture? I have a second carb that I plan to put on but it isn't set up the same and the current carb and muffler were dyno-tuned together.
Any help out there is appreciated.
already replaced: plugs, plug wires, coil.
I also disconnected the tach to see if it mattered and no it didn't. I don't have a spare ignition module so I can't check that.
I did look at all wiring connections and saw no problems.
Any ideas??????
Thanks |
Sparky
| | Posted on Sunday, October 08, 2006 - 01:41 pm: |
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There's lots of things to check. The ignition circuit goes through the neutral switch, side stand switch which you bypassed, the clutch switch, the handlebar on/off switch and ignition key switch.
One test in the manual is to bypass all these with a test wire from the battery + terminal to the white/black wire on the coil. Note: you must disconnect this wire to stop the engine.
You might hook up a timing light and aim it at the timing hole in the crankcase with a clear plastic plug of course. The idea here is to see if the timing mark is jumping around or if it is repeatedly solid.
If it is jumping around, that could be an indication that the pickup sensor is flakey, the timing cup is defective or there is a poor connection in one of the 3 wires out of the cam sensor to the ignition module.
The manual says to test the cam sensor for intermittent operation by spraying a refrigerant on the sensor to see if the engine kills. If not then apply heat with a blow dryer to see if the engine kills. Also repeat these tests on the ignition module.
Also verify that the ground strap between the swingarm mount block and the frame is in good condition.
Happy hunting!
Sparky |
Bad_karma
| | Posted on Wednesday, October 11, 2006 - 02:57 am: |
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s3thunder
I have a two brothers on my 99 s3 and had problem with lose of power in the mid range. What I found was the springs that retained the can to the elbow would allow the muffler to slide back about .5 inches. Two brothers provided me with better springs. That cleared this problem.
Joe |
S3thunder
| | Posted on Sunday, October 15, 2006 - 04:04 pm: |
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Sparky,
You seem to be on the right track with my problem so perhaps you can let me know if you have ever heard of an ignition module being sensitive to cold.
I took my carb off again last week and thoroughly cleaned it with compressed air cause I thought the engine was starving at midrange. It cuts out above 2500 to 5000 but mostly and most violently in the 3000 to 4000 range. After replacing the VOES and putting it all back together I went out for a ride and it all worked just great! Trouble is that was on a warm day, about 80
and then I put the bike up for the week. Today, it was real cold and when I went out for a ride, it was cutting out again. I went back to the garage and let it sit while I heated up the ignition module with a hair dryer. Now, the heat of the engine could have heated other things too, but when I jumped on and went back out, it ran fine for the next hour. I will try heating the module up from start next time to see it this is the trick. I guess this means my module is bad, what do you think?
Thanks to everyone who has put some thought on this. Seems I just have to find another module 32680-96Y if anyone out there has one. |
Sparky
| | Posted on Sunday, October 15, 2006 - 10:29 pm: |
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"perhaps you can let me know if you have ever heard of an ignition module being sensitive to cold"
Well, not exactly ignition modules, but in the aerospace industry, all (mostly all) electronic components undergo thermal (hot and cold), vibration and myriad other tests before they are accepted by the customer. Whereas I have no statistics on failure rates of such components, failures do happen because of thermo-dynamic effects on electronic circuits. All it takes for a module to fail any performance test is something as simple as a random loose solder joint that broke because a circuit board expanded or shrank.
Back to your module, before you swap it out, try some refrigerant spray, available at electronics stores or Radio Shack, on it. Have you disconnected the module and checked its connector pins/sockets?
Another swag for the carb would be to 1) verify the slide moves freely up and down with your finger and, if that's OK, 2) take the carb top off and inspect the carb's diaphragm for pinholes. |
S3thunder
| | Posted on Monday, November 20, 2006 - 02:50 pm: |
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Follow up to this problem of engine missing and cutting out when cold. The usual missing when cold is still a mystery of sorts. After checking the easy stuff, we had to get down to checking the wiring for shorts. It turned out that the pigtail off the ignition timing pick-up was rubbing against the engine case and had chafed through the shield and the insulation layers. On acceleration the wire was forced into more contact, and shorted the ignition. As for the cold, it is likely the higher moisture aided in the shorting out of the wire more easily and more often.
A new pick-up unit from HD solved the problem. Thanks to everyone who helped with suggestions on this one. Anyone experiencing unusual cutting out especially in the 2500-4000 rpm range might want to check out the same pigtail for wear. It can be accessed by taking off the cover over the primary drive sprocket. |
Blake
| | Posted on Tuesday, November 21, 2006 - 02:21 am: |
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Thank you so much for the follow-up! One more data point for the KV! Outstanding! |
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Engine cutting out at midrange rpm