| Author | Message | ||
     Silent_matt |
My '97 S1 just started falling on its face at anything over 4200 rpm at wot. It seems to be getting worse as it used to only do it a little when it was under load and over 5k rpm. Now I can hear it misfire just free reving it. It idles fine and runs great up to that point. I've tested the stator, coil, secondary wires, and replaced the plugs. Puts out over 14v at high idle. The pickup and rotor look good(no contact and not loose). Also cleaned the carb circuits and jets. I've tried pulling the choke when it acts up but it doesn't change anything. It seems like the coil might be breaking down or the pickup or ignition box is dying. I have a new coil on the way, just hate blindly throwing parts at it. Anyone have any similar issues or advice? | ||
| Firemanjim |
What did your plugs look like? And will it rev past if you are not at WOT? (Message edited by firemanjim on November 06, 2012) | ||
| Silent_matt |
Plugs were tan on the electrode, sooty on the ring. It will go a little higher if not at WOT but seems to be getting worse like hitting a wall at high rpm. EDIT: Plugs were tan but as I rode it more and the problem got worse, they turned completely sooty(almost fouled). It will free rev at quarter throttle fine but miss at WOT. (Message edited by Silent_matt on November 06, 2012) | ||
| Pikeben08 |
Vibration related wiring short? Have you check the wiring for any wear through the insulation? | ||
| Silent_matt |
I haven't really done a thorough look, just a quick inspection and shakedown test. | ||
| Thejosh |
Coil getting weaker as the bike heats up. I would put my money on the coil based off of your troubleshooting. Coils are capacitors, which if they overheat can stop working properly. | ||
| Silent_matt |
Yeah, I think(hope) its the coil. I would think there would be some difference depending on ride time but it's always bad. | ||
| Two_seasons |
Maybe your CPS (crank position sensor) is shorting out. Check the insulation really good on the wiring. When's the last time you checked static timing? And what about just making sure your plug wires are within the ohms range. And this always sounds stupid, but are your battery terminals tight? 10mm wrench to snug them up. Also make sure your battery is load tested, may be on it's way out. | ||
| Silent_matt |
The battery terminals are tight and the battery is new. The resistance on the plug wires is in spec, and I swapped with another set just in case. I haven't checked static timing yet, but don't see it just changing abruptly and on its own. The pickup could be going out. I just took the bike out and am able to ride it up to redline at half throttle or less with no problems. | ||
| Firemanjim |
Sooty means rich condition and you said pulling enrichner makes no difference. Maybe enrichner circuit stuck on? | ||
| Silent_matt |
The choke raises the idle when pulled so I think it's working. I think the soot is caused by the lack of spark. | ||
| Sparky |
You might try aiming a hair dryer at the coil (which is a type of transformer, not a capacitor) to see if heat is a factor breaking down the insulation on its windings. With the coil good and hot take resistance readings on the primary (low voltage) terminals and secondary (spark plug) terminals and compare those when the coil is cold. edit: Maybe we've been overlooking the obvious. Have you bypassed the sidestand switch? The ignition signal goes through it and if the switch is bad the first symptom is misfiring. (Message edited by Sparky on November 07, 2012) | ||
| Thejosh |
Well then the transformer weakens when hot. (Message edited by thejosh on November 07, 2012) | ||
| Silent_matt |
That's a good idea on the coil, my buddy gave me a different coil to try while I wait for the one I ordered. I haven't checked the kickstand switch and it did start acting up after I cut the pass. peg mounts off, so maybe the angle of the stand changed something? | ||
| Silent_matt |
Well, the different coil didn't change anything. So either it's bad as well or that's not my problem. I don't think my kickstand switch does anything, it runs with it up or down in gear. I unplugged it and no difference.... | ||
| S1owner |
Jump the wires together on the switch and see if the problem is still there | ||
| Silent_matt |
Jumped 'em, no difference. | ||
| Sparky |
What else did you do when you cut the pass. pegs off? Your problems seem to stem from when you did this. The angle of the stand when up should only matter if the sidestand switch is active and functioning like stock. But you say you unplugged it and there's no difference!? That's not logical because if you unplug the sidestand switch, the ignition is cut off and it won't run. It may start because of the starter interlocks (diodes), but the engine won't run... unless someone has altered the ignition wiring. So what is the rest of the history of this bike? | ||
| Silent_matt |
I didn't change anything other than that. It ran fine for a while after I cut the mounts off, so I don't think that caused it. I bought the bike last month. I don't know what the previous owner(s) did to it. I guess I'll start going through the wiring. | ||
| Bigslug |
Matt, My M2 had similar symptoms a few years ago. After trying many different things, it turned out to be the plug wires were bad. If you have another bike to swap wires with give it a try. Mike | ||
| Cyclonecharlie |
Be sure and check your tank vent and petcock to make sure it's an electrical problem your looking for. | ||
| Silent_matt |
Just put new plug wires on with no change. Maybe it is a fuel issue, I just don't see how considering I've been through the carb twice. This is getting pretty frustrating. | ||
| Sparky |
Another possible cause might be a bad ignition switch especially if you have a bunch of keys dangling from the key switch. That extra weight of keys and engine vibrations can cause the switch to wear out prematurely resulting in intermittent ignition power. One way to isolate this issue would be to temporarily jumper the two wires together at the ignition switch that provide ignition power. | ||
| Silent_matt |
Fixed It! So first I swapped in a known good coil, no change. I grounded the voes, no change. Earlier I enlarged the main jet from the 170(.078") to .089, still no change so I filled the jet back in and drilled it to .073. Now it runs fine! Not sure if maybe it was on the rich side then the voes went out or what. I didn't put the voes back in because I don't have a vacuum pump to test it, but I have eliminated them in the past so I might just leave it off. Thanks everyone for the help, I was ready to tear the bike down early for the winter. |
