Need help with serious problem on '80 GS550L

[Blueandorangefish]

Let me preface this posting by saying that I have gone through the forum archives to try and find answers, but I haven't seen anything exactly like this. I have, however learned a few things that helped explain some stuff.

I was preparing for a ride and had a horrible time trying to get the engine to start. Eventually I did get it idling. After it had been idling for 3-4 minutes in neutral the motor made a odd noise and stopped. When I tried starting it again it would turn over once then stop. Then when I let go of the starter button I could hear the starter spin down. If I tried turning the motor over again it wouldn't at all and I would again hear the starter spin down after releasing the electric start button. Now, if I roll the bike a little with it in gear then try to start it, then it will do the turn over once and stop thing again.

I put the bike up on its stand last night to do a bit more troubleshooting. What I found was that in neutral the rear wheel will spin freely. In gear I can get the tire to spin, with some effort of course, and I will hear the motor turning. If I have it in gear and have the clutch pulled in, I can get the rear wheel to spin, but it takes some effort and I can tell the clutch is not totally disengaging. I read in the archives that the way the wet clutch is designed that it will act a bit like a torque converter, so this may or may not be an issue.

I removed the starter to see how it looked and all the teeth on the gear was fine. Also, I drained the oil and didn't see any particles then removed the cover over the clutch to see how everything looked there. Everything looked very good and I saw no metal debris anywhere.

FYI side info:
--The starter is not original. It was pulled from my '78 GS550 parts bike I was able to get it to fit in there, but it took a bit of doing as it seems that all sizes are just a bit off on the '80 model from the '78. I had to give the starter a bit of help in moving over so I could get the screw holes to line up.
--I did find the hard-starting root problem when I was pulling the carbs off. As it turns out, even though the plug wires for cylinders 1 and 4 were firmly inside the boot, the actual wires inside had basically disconnected and were just arcing across, which totally explains why my motor has been running like it has.
--The first time I had the carbs off I had a terrible time getting them back on, I ended up having to loosen the clutch cable so I could get in there and get things situated. Is there a possibility that I didn't get it tightened back to the right spot and it caused this big problem?
--The transmission has been working flawlessly. I haven't had any problems with it slipping, missing gears, or jumping out of gear.

Should I remove the oil pan to look at the bottom end of the motor to see if there is anything broken there? Or maybe remove the stator cover to see if a gear broke there? Any help you guys could give me would be a great help. I'm really not sure at this point if this is a problem in the transmission, clutch, or motor.

[SqDancerLynn1]

Remove the plugs. Pull the cover on the right side signal gen/ points for the ign, using the large nut 19mm ? Try turning the enging over by hand If it will not turn Ouch !!!! The cam chain may have jumped & bent a valve. ANother good indication would be to go and check the valve clearances

[Blueandorangefish]

Well I have traced it down to a problem somewhere around the cam chain/tensioner. Without the cam chain tensioner installed the engine will turn freely. When I tried reinstalling the tensioner I could not get it to seat fully. I put my finger in the hole to feel for an obstruction and could feel some piece of metal partially blocking the hole. If I manually turned the engine while trying to install the tensioner the obstruction would finally move enough to get it installed. When I again manually turned the engine over the obstruction hit the tensioner and would not allow the engine to turn over further.

Is this indicative of the cam chain breaking, and if so is fixing it a project better suited for an overpaid professional to take care of?

[arveejay]

Sounds like part of the tensioner is still in the whole. It should just be a round rod. Try a magnet if the rod is still in there. Have you got a pic of the part you have out?

[brveagle]

I don't think it's the cam chain tensioner, i think you've broke your cam chain. If i were you, i'd remove your valve cover, and take a look at your cams and make sure the timing is still on, and that you didn't jump a tooth.

Keep us posted.

[Blueandorangefish]

The tensioner is fine, but I'll definitely post a pic of whatever carnage I find when I get the valve cover off. Now for the newbie question of the day...how do I determine if the timing is still on once I get the cover off an am staring blankly at it :shock: ?

[brveagle]

The tensioner is fine, but I'll definitely post a pic of whatever carnage I find when I get the valve cover off. Now for the newbie question of the day...how do I determine if the timing is still on once I get the cover off an am staring blankly at it :shock: ?

Remove the valve cover, as well as the right side of the engine cover. Once this cover is removed, you can manually turn the engine over via the crankshaft. Then you can see what's wrong.

[Blueandorangefish]

Well, some good news to report. I pulled of the cam cover and the chain is sitting pretty still intact. My problem has to lie somewhere around the cam chain tensioner. I've looked for an exploded diagram of my motor to see if I can figure out what the obstruction might be, but I can't seem to find one. I've included a photo of the obstruction, which looks to me to be whatever the end of the tensioner presses on. Is it possible that whatever holds this piece in place broke off?

[arveejay]

Ya got a pic of the tensioner?

[brveagle]

Bluefish~

It's very unlikely that that peice is your problem. What the cam chain tensioner (CCT) pushes on is the cam chain guide. It runs from the top of your crank, past where you see it now, till the top of the valve cover. It's pretty much locked in place by the tension of the head pushing it down.

[hungryman]

Cam chain tensioners do not just push back when extended. They typically need to be brought back in by turning a screw or something. The one on my XR650R had a slot for a screw and when turned pulls the tensioner back in. Check your manual.

I wouldn't turn the motor over without the tensioner in place. You can skip a tooth on the cam chain pretty easy.

[jimcor]

Phewww, OK, my .02.

Get a shop manual, you're going to need it.

Your problem began when you forced an improper part, the starter, on to your engine. The starters for the '78 models, there were 2 used, a Mitsuba and a Nippon Denso, are different than the 2 brush Nippon Denso used on the 80 550L. Start by removing the 78 starter and repairing your '80 model.

Hopefully nothing was damaged in the starter clutch when you ran the engine with the wrong starter. Something was binding and removing the improper starter will let you know one way or the other if you damaged anything else.

Brveagle was right that movable thing you felt in the tensioner cavity was the cam chain guide/slipper.

Next, you MUST do this. Check the valve timing. You must check to make sure your turning the engine with the cam chain tensioner removed has not allowed the cam chain to skip teeth. That's what you need the manual for.

The manual will also explain how reset the tensioner.

Hopefully using the correct starter will get things back on track for you.

Next time remember, when something screws up the first place to look is the last thing you 'fixed'.

I mean, I know, I'm not the only guy that ever did carb repairs starting with a brake job.

[arveejay]

On the side of the tensioner is a screw with a locknut around it. Loosen the locknut, loosen the screw, turn the big knob on the side(the one with the big spring around it)push the pin in and hold it in, tighten the screw. Install tensioner on motor, loosen screw till pin moves (you'll feel or hear it), tighten screw then back it out 1/4 turn, hold screw in place and tighten locknut. I would remove pin, clean and lube with motor oil before installing if it were me.