Sorry, übersetzen wäre zu viel.
Es geht um die stark modifizierte TZRG500 vom Randy N. in den USA, der bricht morgen zum großen Treffen in Barber auf, was er selbst über Monate auf die Beine gestelt hat und stößt seit gestern auf folgendes Problem:
Wäre Klasse, wenn einer seinen Hirnschmalz mit einbringen könnte! 
Gruß
Carsten
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..."But I didn't change anything!"
The mating call of the delusional troubleshooter.
Here I was, playing with cosmetic stuff on my bike, because as I knew, the bike was running JUST FINE last time I ran it. So, there was pretty much nothing to do mechanically.
Of course, over the winter I had tied up about 20 loose ends and half-assed bits of work.
So Sunday morning I finish welding up my mufflers to fit the new tail (sob story on that later) , put the pipes on the bike, start it and go for a roam around the neighborhood. It ran perfectly. Since I had taken 8 degrees off the disc closing, it had much better manners around city streets than it did last fall.
"check!" I think to myself. Bike is mechanically ready to go.
So, about 9 PM last night I think to myself, let's go for a serious rip, the freeway is looking kind of deserted. The bike even pulls out onto a steep uphill from the hater right-turn-on-a-hill stopsign, without protest. wahoo!!
I head for my favorite ramp, give it the berries, revs come up, it starts to hike up its skirts to GO, and BLAGHAGAHAGA POP OPO POP BLAUGHHHH
WTF??? Maybe out of gas? I didn't put very much in it. I limp down the freeway to my offramp and scurry back to home base. No, I had reserve + 1.5 gallons of gas, but maybe one fuel line is kinked? I flow test both sides, replace the suspicious looking kinked fuel line, top up the tank, and try again. same result, but worse.
This time I get home and download the datalogger. right about 8500 rpm, the left two cylinders go cold while the right two cylinders keep climbing. what the HELL??
it's not the coils- one feeds front cyls, one feeds rear cyls. left and right fuel lines.. what else is there??
Long story short:
I check all float levels, all jets, swap rear carbs from left to right. swap plug leads, switch the tach pickup between crank trigger and magneto, powervalve on and off, headlight on and off, verify all CDI parameters, put in a fresh set of brand new iridium plugs, air filters on, air filters off, clean oil out of the air filters, tear the wiring harness apart and look for some mysterious short or bad wire or wrong connection that I may have screwed up while tidying up, put in an override switch for the main air jet solenoid, check compression (all good) oh yeah the oil pump was hanging halfway open.. AHA!! cable is getting dodgy. I spend about 2 hours trying to get it smooth enough to close properly. NO difference. at 3 AM I finally gave up and went to sleep.
Today I thought- well, I DID change the disc valve timing, reduced it by a lot. maybe the jetting for the long discs is totally different that for short discs? so I start changing jetting all over the place. And the bike is getting worse, and worse. now I can barely ride it, opening the gas in the neighborhood at 5000 rpm gets me banging and barking. sonofabitch! track day slips by while I troubleshoot frantically.
maybe it's the premix? too much for putting around? I go and get 5 gallons of clean Amoco 91, and swap out the 100:1 premix. no change!
Out of frustration, I gas it a little bit and the misfiring and breaking up is crippling from the instant I open the throttle. it's worse than ever.
On all these runs, the datalogger shows the left cylinders dropping cold as the bike starts to misfire. why?? bad case sealing? it was all so happy last fall! and it ran so great a day ago!
I think, maybe it's totally loaded up. I give it a serious banging and barking flog down the ramp. come home, and look at the data...
left rear and right FRONT cylinder went cold this time.
WHAT in the HELL is going on. I did not change the front carbs, and the coil leads have been unchanged for the last 8 rides.
MAybe.. the ignition is going south for some reason. And there as it goes weak, there is only enough juice for one plug to fire? one runs, one goes dead? On each coil, I had one cylinder drop out. I think it was just an accident that both went out on the right side, sending me on a 24 hour goose chase. Well, now on the front pair, the right front cylinder dropped out. AHA. mister electrical fault, you have showed your hand.
Cool, you can see a misfiring plug very clearly on the EGT. it just takes a nosedive and goes cold.
So, after checking 100 mechaincal things (oh yeah, I have half the disc valves out- franco's discs are 10 thou thinner than my old carbon ones and I have about 30+ thou clearance- bad for starting and low rpm manners, so I'm shimming all the disc covers)
it appears to be electrical. and it's getting worse in a hurry.
It occurs to me that I never had my new stator epoxy-coated- maybe I have some wires that have started to short through? and I did have the stator off over the winter. maybe something is shorting under vibration as revs increase. Anyhow- I'm dealing with something where I have no spare and no way to fix it if needed.
have you ever had a setup with a twin-lead coil, where one cylinder dies and one runs?
I used to run total loss system on my RD350. when the battery got low, one cyl would fail and leave me droning on the other cylinder for a few miles before it went dead totally. I have a feeling this is the same kind of thing.. something going weak in the spark, but it's enough for one of the paired cylinders to run. not both.
Well, I have 48 hours till departure. never thought I'd be troubleshooting basics at THIS point.
HEY, I did put on a new battery this summer, too. the old one was shot. but-- another variable. it's charging nicely and has nothing to do with the ignition, but there's another variable. damn, lotta variables.
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So I am thinking, WHAT has changed specifically with regards to the ignition, since my last ride (last winter!)
Well, I did remove and reinstall the magneto- maybe I put it back on the wrong keyway?? (it has two keyways) unfortunately I already removed it and I did not note which keyway it was on
I removed the B8ES plugs that I ran all last fall and installed Es-ZU plugs (which I then swapped for new iridium plugs, hard to think there's a problem with new iridium plugs)
I do not run resistor caps but I do run inductive suppression wires. I had all the wires off while fooling with plugs, and they ARE close to lots of other stuff. maybe a spark is jumping to earth somewhere?? Russ suggests running it in the dark and looking for discharge
The CDI was never removed but I did plug it into the programmer- chance something got changed- altho I checked all settings vs my log book and all are OK
here's what the logger shows. I'm keeping it simple and showing the front pair of cylinders. normally, the EGT from both cylinders rise and fall pretty much in synch.
sunday night- hits 9600 rpm and misfire sets in . blue line is acceleration in G. See where accel peaks and starts to come drop- that is where misfire started and acceleration dropped off. light tan line is left front cylinder. dark brown line is right front cylinder. and once it misfired - it stayed cold for quite a while, cruising down the freeway at light load it eventually warmed back up and matched the right front again.
(hier Datarecording mit 9600rpm betrachten)
now, here's a run today. the RIGHT front cylinder drops out, but now it's happening at 5000 rpm. Right front goes cold and left front keeps working.
both plugs are powered by the same coil. I did not swap the front carbs. so, the misfire jumped from left to right side today. On the rear, misfire has stayed with the left side. installing brand new plugs made no difference, in fact it is steadily getting worse no matter what I change or swap!!
(hier Datarecording mit u.a. 5100rpm betrachten)
too tired to work or think anymore and starting to get a little bit of despair!
RN
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Thanks again. I made a little diagram to help me think and realized some other potential trouble spots.
I changed my throttle lately to a quick-turn housing from an RS250. Well. so I had to add a separate kill switch (new) am using a spare CDI map switch, it's meant for a bike should be rugged enough. but, it's new so unknown. perhaps some issue with that wire or switch?? kill lead only has to touch ground to kill the motor.
I dug up the stock coils and will swap them on today after fixing the danged disc seal I broke- seems unlikely that both are going bad, BUT, their primary windings ARE connected to each other. of course I will have to cut up my beautiful high tension leads and take off the end caps.. oh well. crap, more mounts to create.
DO STOCK COILS NEED TO BE GROUNDED? just making sure. do they?
there is a common power lead feeding both coils from the CDI. any shorting or grounding on that wire would hit both cylinders simultaneously. will check or re-wire it
connectors from CDI- will check again but all are so new (less than 2 y.o.) and squeaky clean
I have tapped into the crank reluctor to drive the tachometer. maybe that lead is dodgy or bad. I will check that and swap in a new reluctor as well.
Last year, I went to start the bike and it was dead. The CDI had failed while sitting, parked. so I swapped on a new CDI. I have one spare left- will swap CDI as well, after previous steps. What the heck is up with that.
I have to button up my motor guts (carbs and discs off) and start packing the trailer at some point, at least I know what I will do today!!
misfire starts on both coils at the same instant so it just HAS to be something in that circuit, wish I had been this logical before but that both-left-side thing sent me down a wrong path
thanks again for the tips, guys
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