Serious chain problem

[sam206]

Hey everybody,

This afternoon I went on a nice ride to get my chain warmed up before cleaning and waxing. Got home, put bike ('81 GS 750 EX) on center stand, cleaned up and applied wax, which I let set for about 5 minutes. I put the bike in gear to check the chain and sprocket, and out of nowhere I get a loud clunking noise, a LOT of play in the chain (mainly side to side), so much so that I immediately killed it for fear of the thing rattling apart. I checked my tension and it was a little loose so I tightened it, thinking that might fix the problem. It didn't. From the sounds of it, the problem is in the gear box, but hopefully not in the transmission. I haven't taken the cover off yet to take a look (I had to go to work and leave my project unfinished!). I'm a total newb, so if this is an obvious problem, my apologies. Any ideas? Thanks.
-Sam Hushagen

[hampshirehog]

Sounds like your gearbox sprocket has come loose. Pull the cover and have a look.

[sam206]

I'll open her up first thing tomorrow. Any ideas for causes? I did just get new tires...

[koolaid_kid]

There is a nut which holds the front sprocket on the splined shaft. There is a lock washer that prevents the nut from loosening. If the lock washer was not locked down (or missing), the nut could have loosened. It's a long shot IMHO, but possible.
I would sooner suspect the spacers that go between each tensioner bolt and the axle, since that entire assembly would have been removed and reinstalled by the tire installers.

[sam206]

Much to my chagrin, when I took the cover off I found nothing obviously loose or out of place, nor any significant wear on the front socket. Fired the bike up to watch everything work, and there was none of the loud noises or side-to-side play in the chain that I was getting yesterday. The bike was definitely hot when the problem occurred yesterday, but I'm not seeing any of the problems now that its cold. Any suggestions? I don't trust that this won't happen again when the bike is warmed up. I had been riding in stop-and-go traffic in warm weather yesterday, with lots of shifting. Could the problem be transmission related? The bike does tend to jump into first gear from neutral. Maybe a clutch adjustment? I'm definitely at a loss! Thanks!
-Sam

[Mysuzyq]

Is the chain itself in good condition? If it has a few knackered links, tension will not be consistent, regardless of attempts to adjust......at some points in it's rotation it will seem loose, but bind and tighten up as it goes around. Check tension at various points of the chain's length by turning the wheel, to rule this out. If it does have tight spots, it may be time for a new chain.
Tony.

[rapidray]

Sam, when you have the bike running on the sidestand it will make all kinds of noises that you aren't used to hearing & will freak you out! Don't sweat it, it's all good if all your parts are tight. Ray.

[paco13]

Just to be clear, were you running it on the centerstand, wheel elevated, to watch it go round?

[ryonker]

Hey everybody,

This afternoon I went on a nice ride to get my chain warmed up before cleaning and waxing. Got home, put bike ('81 GS 750 EX) on center stand, cleaned up and applied wax, which I let set for about 5 minutes. I put the bike in gear to check the chain and sprocket, and out of nowhere I get a loud clunking noise, a LOT of play in the chain (mainly side to side), so much so that I immediately killed it for fear of the thing rattling apart. I checked my tension and it was a little loose so I tightened it, thinking that might fix the problem. It didn't. From the sounds of it, the problem is in the gear box, but hopefully not in the transmission. I haven't taken the cover off yet to take a look (I had to go to work and leave my project unfinished!). I'm a total newb, so if this is an obvious problem, my apologies. Any ideas? Thanks.
-Sam Hushagen

I am no expert, but I am pretty sure the only things that would affect the chain movement are;

1. Checking that front sprocket, which you did. One of my bikes did have a loose front sprocket.

2. A bad chain

3. Possible a loose rear sprocket. These loosen up sometimes.

4. Your rear tire is somewhat out of alignment.

Look for any unusual wear on the sprocket teeth.

If all the above are ok, you are good to go.

Rick

[sam206]

to paco, yes, bike on the centerstand, wheel elevated to watch it rotate. Is there any chance that this may be transmission related?

[BassCliff]

Hi,

When was the last time you changed your oil? What kind of oil are you using? Are you carbs leaking gas into the oil and diluting it? Just wondering.


Thank you for your indulgence,

BassCliff

[paco13]

With the wheel off the ground your chain will have more play/slop, combine this with no load/resistance and you will hear and feel all the lash,slop,play combined from chain, sprockets, splines, cush hub,and trans gears. If your idle isn't smooth or low it will make it worse. The chain might of been slapping the swinger near the pivot, or the inside of cover from the extra play and the angle of the swingarm. I think you are ok. Make sure you didn't over tighten the chain now. Adjust with weight on bike, preferably with swing-arm parallel to ground.
To tight will make noises too.

[madjack57754]

Sounds like transmission/ clutch snatch noise. A normal thing when the wheel is not loaded and the bike is in gear and running in gear to lube the chain. Out of sync carbs tend to make the noise worse.

[Rick65Cat]

The bike does tend to jump into first gear from neutral. Maybe a clutch adjustment? I'm definitely at a loss! Thanks!
-Sam

WHOA!! Jumps into 1st...all by itself?!?! Or do you mean with a light touch of the shifter lever?
A motorcycle tranny should NEVER decide by itself to drop into gear if it feels like it.
Picture yourself sitting at a red light after having put it in neutral so you can sit up and maybe stretch your back or adjust your gloves and it pops into gear without you being ready...best you can hope is it just stalls. Or maybe you just lurch into the car ahead of you and fall over.
Worst scene? You are the 1st vehicle at the intersection and you lurch out into cross traffic...a death sentence.
This needs attention right away if it does it by itself!!

[sam206]

Rick, no, it doesn't jump into gear by itself, but when I put it into first i get a pretty healthy clunk. Thanks for all the tips guys. I'll keep an eye on things and let you know.