This is on the 5 valve yamaha motor in my MZ. However since the smartest dudes+dudettes on the planet reside here (and I am not being sarcastic ... the rest of the mototcycle forums are pretty bike wanna be's comared to the gstwinners) I thought I'll post here.
Motor cranks nice and good, and does not start.
The motor has spark. Even looked bluish in the sun.
Motor has gas - in fact I sprayed starter fluid and even managed to start a fire @ the intake manifold. No damage done, but it did burn a few sec, till I snuffed it out.
Motor has compression.
Motor has valves adjusted nice and good.
It turns over nice and good, and does not fire. Not even mis-fire.
Now to back up a bit.
April 2012 I had a friend ride it and it stalled on him and he trucked it back. I got it started a few times and it was a hard one to start. Took 100 tries it looked like. Then I pulled the ignitor box apart and tested one and only transistor it has in it as bad. I replaced it with a suitable equivalent. That made it easier to start, and it was started quite a few times with that, and I got it out on a 30 mile ride in october 2012. However on the exit ramp it stalled and it has not even coughed or misfired since.
I replaced the ignition trigger earlier last week. Nothing - same as before. I can see the spark, it however isn't igniting the mix.
It has a iridium spark plug which I would change next ... probably today. But anyone else have any ideas.
Cool.
buddha.
load it in fordzilla and take it to the bike cave. course thats a long drive Eh? lol. is hte pickups/trigger adjustable by chance, have you put a voltmeter on the coil to see if you get voltage when youre supposed to and not before/later?
OK......I will throw my hot in the ring :thumb:
You are describing what could be a weak or loss of spark spark under compression.........in turn this means the HT lead breaking down or the coil/module has crapped out.
Its seeing enough voltage to spark outside the cylinder where its at 1 atmosphere (14.7psi) but not enough when its in the pot and at 150psi +.
A spark needs about 75v to jump a thou` but that figure rises when the air surrounding it is under pressure and becomes more dense.
You need something that will verify the voltage at the plug.
Yama - I got voltage with the old trigger too, the new one I do believe I would be getting voltage. I will check to be sure.
Sledge - it would misfire in that case wont it. Nothing, nada.
OK so bad coil, test the trigger to be sure, and can it be a bad spark plug - I dunno how old this plug is, but 2011 spring I got it, and I've not put a new plug in it.
Its got same as GS, but the one in the bike is iridium.
Cool.
Buddha.
Quote from: The Buddha on September 16, 2013, 10:46:50 AM
Sledge - it would misfire in that case wont it. Nothing, nada.
Not necessarily, it might not be be giving any spark at all when under pressure :dunno_black:
Did you ever touch on Paschens law at scool/coll/uni?
Voltage required to bridge a gap........ depends on gap distance and gas pressure; V=f(D*P).
Quote from: The Buddha on September 16, 2013, 10:46:50 AM
Yama - I got voltage with the old trigger too, the new one I do believe I would be getting voltage. I will check to be sure.
Sledge - it would misfire in that case wont it. Nothing, nada.
OK so bad coil, test the trigger to be sure, and can it be a bad spark plug - I dunno how old this plug is, but 2011 spring I got it, and I've not put a new plug in it.
Its got same as GS, but the one in the bike is iridium.
Cool.
Buddha.
im sure you had answered this already. heres an idea if youve access to them, hell in charlotte, id say you do. but an old chevrolet ignition coil. ive used them on my gs before. spark should be white not blue or yellow if memory serves. almost willing to bet the broken pig that coils if not dead, are dying. or were in process of doing so when it died on you and other person.
Quote from: sledge on September 16, 2013, 10:58:17 AM
Quote from: The Buddha on September 16, 2013, 10:46:50 AM
Sledge - it would misfire in that case wont it. Nothing, nada.
Not necessarily, it might not be be giving any spark at all when under pressure :dunno_black:
Did you ever touch on Paschens law at scool/coll/uni?
Voltage required to bridge a gap........ depends on gap distance and gas pressure; V=f(D*P).
I dont quite remember it with the name paschens law - dont recall that ...
However pressure makes its resistance higher, but other atomized fluids can make it lower.
I'm more thinking I am getting spark when its in the intake cycle ... cos I lit up the manifold pretty good. I'd suspect either the TCI or the spark plug itself. I doubt there is spark in air but not in mixture. I dont think I am waling that fine line.
Cool.
Buddha.
could spark, err the pickup be backwards err 180 deg off?
Quote from: yamahonkawazuki on September 16, 2013, 11:25:09 AM
Quote from: The Buddha on September 16, 2013, 10:46:50 AM
Yama - I got voltage with the old trigger too, the new one I do believe I would be getting voltage. I will check to be sure.
Sledge - it would misfire in that case wont it. Nothing, nada.
OK so bad coil, test the trigger to be sure, and can it be a bad spark plug - I dunno how old this plug is, but 2011 spring I got it, and I've not put a new plug in it.
Its got same as GS, but the one in the bike is iridium.
Cool.
Buddha.
im sure you had answered this already. heres an idea if youve access to them, hell in charlotte, id say you do. but an old chevrolet ignition coil. ive used them on my gs before. spark should be white not blue or yellow if memory serves. almost willing to bet the broken pig that coils if not dead, are dying. or were in process of doing so when it died on you and other person.
Oh coil - I have some GS crap I can toss @ it. GM ignitor - people have swapped those in.
Cool.
Buddha.
Quote from: yamahonkawazuki on September 16, 2013, 12:14:34 PM
could spark, err the pickup be backwards err 180 deg off?
It cant be 180 out cos the thing only has 1 spot to bolt in - its 1 cyl, the rotor carries timing mark, that also cant be off, its indexed with woodruff key. However the 2 prongs coming off it can be inverted - but I am sure in my case - I have tried it both directions and same result.
New plug gonna fix it, I never liked that iridium crap.
Cool.
Buddha.
Oh hoh hoh hoh ... the spark out of that iridium sparkie be it old as it is, will still knock the daylights out of the new ngk dpr8ea9.
I have it in the bike ... I suspect the bloody ignition box is bad now.
Cool.
Buddha.
Are the valves adjusted in time with the crank? I remember when i rebuilt my GS, i had the cams one tooth retarded and it would not run unless i had full choke and WOT.
if not, I vote new plug, then new coil, then new ignitor.
It probably isnt the pick up coil, but thats worth doing a test on just in case.
Quote from: Funderb on September 16, 2013, 05:30:38 PM
Are the valves adjusted in time with the crank? I remember when i rebuilt my GS, i had the cams one tooth retarded and it would not run unless i had full choke and WOT.
if not, I vote new plug, then new coil, then new ignitor.
It probably isnt the pick up coil, but thats worth doing a test on just in case.
I will check timing again, but this bike only has 1 cam shaft, the intake and exhaust cant change with respect to each other.
In fact If I had a issue in the woodruff key on the rotor/crank I may have timing off.
The iridium plug has mondo spark, way better than the new ngk I got.
Pickup coil - I swapped it for somehting that may be in correct ... But have the original, may have to just go back to that. It may be working fine.
Cool.
Buddha.