A little pop, and now it's dead :(

[Anonymous]

I went to start my '79 GS550L today, it cranked over but didn't quite catch, then I tried again, it turned over, POPPED once, then died. It wasn't an exhaust pop, more like something that popped off from somewhere in or around the motor. Not too loud, either. The starter now makes its healthy crank sound once, but the engine won't go at all. Nothing. What the ...????

Frozen engine? Plenty of new oil in it, and it was running fine the other day. Ignition problem? Timing chain snapped or something? Where should I start looking?

I saw no smoke, smelled no fluids, and saw nothing that came off. The noise seemed to have come from the braking side of the bike. Please help!

[Mark Harrop]

pop

I'd pull the plugs and try it again. Sounds like you may have gotton some gas drainage into one of the cylinders. I was a little confused about your post. Which side is the "braking "side? Does the starter continue to run when you hold the button in? Was the bike on the kickstand or center stand?
Tape two drinking straws together and drop it in a spark plug hole. If the straw goes up and down while you crank the motor, the starter is working properly, and the problem lies elsewhere.
If the cam chain is broken, you may have a big problem. I'm not sure if you pistons will contact the valves if the motor is spun with the cams stationary. I would not proceed untill this is clarified.
Can anyone else help out?

[Anonymous]

Thanks for the reply .... the braking side is where all the brakes are: if you're on the bike, it's your right-hand side. I've heard the term before, I thought it may clarify things, lol.

The bike was on the kickstand when it happened. It's possible I may have gotten gas into the cylinders as I was trying to prime the carbs, however I didn't have the gas flowing for more than several seconds. If that is what happened, I can just drain the oil and put some new stuff in, and I'm set, right? The motor never turned over at all after the pop, I just hear the starter cranking.

I'll try removing the plugs tomorrow and see what I can see. I'll try to figure out the pistons and valves situation somehow. Maybe I can find something in the repair manual?

[earlfor]

Re: A little pop, and now it's dead

The first thing I would do is with the bike on the centerstand, look in the oil level sight glass. If your petcock is leaking, the oil level will be above the window and you will be unable to see your oil level. If the crankcase is over full with a combination of oil and seeping gas, you can have hydrolock and the starter will not turn the engine over. If this is the case, its your good fortune the engine did not start. :-)

If the oil level is between the high and low marks on the sight glass, then I would next remove the points cover (right side of engine at crankshaft) and remove the spark plugs. Then with spark plugs removed, take a 19 mm wrench and very gently and slowly rotate the engine CLOCKWISE with the wrench. (do not use the starter for this) Do not back up the engine...meaning do not turn it counterclockwise. If you can turn it through a couple of revolutions easily with a wrench and hear or feel nothing, let us know and we'll go from there.

Earl

I went to start my '79 GS550L today, it cranked over but didn't quite catch, then I tried again, it turned over, POPPED once, then died. It wasn't an exhaust pop, more like something that popped off from somewhere in or around the motor. Not too loud, either. The starter now makes its healthy crank sound once, but the engine won't go at all. Nothing. What the ...????

Frozen engine? Plenty of new oil in it, and it was running fine the other day. Ignition problem? Timing chain snapped or something? Where should I start looking?

I saw no smoke, smelled no fluids, and saw nothing that came off. The noise seemed to have come from the braking side of the bike. Please help!

[Anonymous]

Thanks, Earl, I'll try tomorrow and report back. I know that the motor could get hydrolocked due to gas, so I only tried turning it over a coupla times, then gave up.

I was thinking, since I added a fuel cutoff switch ahead of the petcock, could someone have been screwing with it? It's a little switch, red, very prominently sticking out from the bottom of the tank. And I did smell gas the other day when approaching the bike, but couldn't find anything wet or otherwise remiss. I wonder ...

[earlfor]

This is insane that the censor ####'s out the word susp icion.

Earl


If you smelled gas and it locked up when you tried to start it, my immediate suspicion is hydrolock.

Earl

And I did smell gas the other day when approaching the bike, but couldn't find anything wet or otherwise remiss. I wonder ...

[Anonymous]

It would be weird if it turns out to be that, though at least it's a simple enough fix. But when the petcock was stuck on PRI, and everythig was flooidng out, I changed the oil just to avoid this problem. However, the oil was clean as can be ... And now that I found a way to shut the fuel off - with the cutoff switch - it starts seeping gas into the motor 'cause someone tampered with it? It's not like the fuel flow increased due to the switch being there. Strange, but that's what it's starting to sound like.

I wish I could have given it more time this afternoon, it would likely be fixed by now.

[Anonymous]

I think I found the problem .. there IS gas in the crankcase. I pulled the first spark plug out, and a little gas FIZZLED out of it like soda out of a shaken pop can. That one and the next plug, of course, stank of gas and were wet. The next two were OK. When I opened the filler plug, it reeked of gas. And I have less gas in my tank than I did the last time, though the bike hasn't gone anywhere.

So it looks like some joker turned on my jerry-rigged petcock at some point, and gas went into the crankcase. A change of oil shold do the trick, I guess, but I am still worried about the POP I heard. After the oil is changed, I'm going to turn the motor over by hand as described by Earl. If it's ok, then I'll try starting her up.

Unfortunately, the only person that can get me to an auto parts store for some fresh oil (I only have a quart at home) is my dad, and he's having one of his "tragic" days. Ho-hum. I guess it's gonna have to sit there for a few days, till I get the oil and then the time to get it all done. This sucks, but ahhh well ....

[earlfor]

That "pop" you heard was most likely a piston stopping abruptly when asked to compress a liquid.

Earl

[quote="Gabriel"]
but I am still worried about the POP I heard. After the oil is changed, I'm going to turn the motor over by hand as described by Earl. If it's ok, then I'll try starting her up.

[Anonymous]

Thanks for cofirming that, that's what I am hoping it is too. But just to be safe ...

I regret to say, and I really do regret it, that I'm gonna have to put the bike up for sale as soon as I make sure she's still running. I've made daily drivers out of cars older than this motorcycle, but I've always been able to find parts for them. Not so with this one ... Everything is a big hunt when it comes to even the most (seemingly) common parts. If I had a car or another bike, and a garage to stick her in, I wouldn't even think about it as I could restore the bike at leisure. It's too bad, 'cause as far as older metric cruisers go, the GS is tops IMHO. I was hoping it could at least be my starter bike - I still haven't even been able to ride it yet! - but I'm gonna put money away for something much newer.

Thanks again for the help, I'll post back here as soon as I confirm all is well. And I'm not gonna sell the bike right away - it'll be a few weeks - so hopefully I'll get a few rides in before it's gone! Now if I could find a ground-up, completely restored GS550L somewhere locally for $1500, well then ...

[Anonymous]

For future folks doing a search on this topic, and for everyone who helped, here are the results: Turned the motor by hand (open-end on the crank bolt) a few times, very slowly, after removing all plugs. Everything sounded OK. Checked the first plug hole, which happened to be at TDC, and I could SEE the gas in the cylinder.
Drained oil. Just before it all finished draining, turned the motor over about one and a quarter turns, VERY slowly, just to finish getting all that gas out of there. Anyone who took an unknowing sniff of the drain pan would have sworn I ws draining the gas tank.
Removed oil filter. It's new, and HELL to find, so I wanted to save it if possible. Smelled faintly of gas, let it drip dry, then gave it a very thorough bath in fresh oil.
Put everything back together. Had to leave for a while, came back, tried turning on the engine. Fired up beautifully. Awwwwwwww YEAH

I let it warm up, gave it some gas. No probs, other than that the idle is still a little iffy (shuts off sometimes). Sure sounds smooooooth, though.

Thanks again for all the help!

[earlfor]

Glad to hear all turned out OK. :-) :-)

Earl

[Anonymous]

I don't know about in Florida, but an Autozone or two carry the oil filters here. They also come with the filter cover o-ring.

[Anonymous]

Thanks, Earl, you had a big hand in helping me on this one.

78gs, the filter is available at Napa, and is not a special order - but I still had to spend well over an hour trying to get my grubby little hands on the one in there now. Could be due to the lack of knowledgeable salespeople here in Miami. At least I have a part number to go by for next time.