I'm new to this forum and not quite a GS owner. I'm really in need of GS help though as enthusiasm and good will have long depleted.
My father bought and owned a 1984 (I know this may not be the correct year but that's its registered date) UK GS550e - black with orange/red stripes in 1999. He become too old for it so I tapped up my father in law who loves his late seventies bikes. I explained how well looked after and how reliable it was. He bought it in 2010.
Since then he has ridden the bike once, it went 10miles and then stopped. It would not restart. He has not ridden it since (over a mile). We have lavished numerous hours and money at it.
The symptoms are, the bike starts - only with choke on - first click. Runs only on three cylinders. The 4th cylinder exhaust is 27degs C with an IR gun and can easily be held with your hand. If you run the bike for around ten minutes at about 2000rpm it runs on three quite reliably. Then, without warning stops - like someone has hit the kill switch! The engine will not re-start. Doesn't fire on any cylinders. If left for about two hours it then re-starts and runs exactly as before BUT the cylinder not working is not the same one as last time!
All four cylinders have taken their turn in being the dead cylinder. It is not isolated to any in particular and none are more commonly the dead cylinder than any other. When the engine dies, the neutral light is still bright. The battery has good charge. There is fuel in all of the float bowls. There are sparks from 3 spark plugs. The dead cylinder, naturally , has a wet plug - the others look fairly normal. The vac at idle is disappointing, but I strongly suspect that is because the idle stop is jacked to allow the engine to idle at 1000rpm with one dead cylinder
My memory is a little hazy over the 7years we've been at this so if at any point I contradict myself I apologise. The compression is 125PSI on all four cylinders, the valves clearances are all correct to book, engine is run with a new aux fuel tank.
What we've replaced: short engine, rebuilt cylinder head, two sets of carbs, intake rubbers, air filter, HT leads, spark plug caps, spark plugs, two sets of ignition coils, three batteries, crank position sensors (ign pick-ups), charging stator, regulator/rectifier.
When we first tested the bike cylinder 1 was 75PSI and didn't get better with oil down the plug. So first step was HG change and head rebuild. Did that and no improvement to the 75PSI. So we swapped the short engine over. The batteries kept going flat so we swapped the stator and fitted a new R/R.
I live 150 miles from the bike/in-laws. So I'm semi-reliant on his feedback and info. He is very hacked off now. And I feel very stupid as I recommended the bike to start with. The only things that I think are relevant and never been changed are: cylinder head, wiring loom and the igniter. Any suggestions?
Cheers,
Glen.
PS. sorry for the long essay
Comment