Topic: Chain fell off today - what the heck went wrong?!

[jdubb1977]

Hey guys, this one really surprised me.  Stopped at a red light today after running some errands.  Took off, shifted... and rolled to a stop.  My chain had literally fallen off in the intersection, and I pushed my '75 750F a mile to my garage.  Not fun!!

The recent history: 
new RH heavy duty 530, 102 link chain (w/ clip style master link), installed about 300 miles ago
new JT sprockets, front & rear (17/48, which is stock & what I had on previously), installed about 25 miles ago

So what's my problem here, and what now?  Get a new chain?  Replace the master link w/ a rivet link?  I was lucky being so close to home, but I've never had this happen before.  Help a brother out!

[scottly]

Sounds like you may have miss-installed the master-link clip? Did you follow the "fish swims upstream" rule?

[jdubb1977]

I THINK I installed the link clip in the correct direction, but it's impossible to know how.  My previous chain had a link clip, and I never had a problem with it. 

calj737, nothing prickish there.    the chain is new (300 miles on it), and the tension was fine when I installed it.  I just checked the adjusters, and they're both equal.  Most of the time when something goes wrong, I assume it was my fault.

I should have mentioned that I found the master link (the portion w/ the pegs, but not the plate or clip) near the chain.  So the weak point was definitely the link, although I'm not sure what caused it to fail.  Not sure how long i rode w/o the clip!

[scottly]

I've never had any problems with clip-type master links, once I learned how to properly install one.

[jdubb1977]

aaaand, just to sure, the open end of the clip should be facing toward the front of the bike when on the bottom of the sprockets?  (and toward the rear when on top?)  yeah? pretty sure that's how i had it, but we'll never know!

[scottly]

Yes, that is correct, but you also have to make sure the side-plate is pushed on far enough for the clip to fully engage the grooves in both pins. The clip should be pushed straight onto the pins, not bent into place, one leg at a time.

[ekpent]

Been awhile but I have had to take a small c-clamp and filler block before to push the sideplate on the pins before I could install the clip.

[scottly]

I've had to squeeze the side-plate on with pliers before, to fully expose the grooves.

[PeWe]

The clip and master link must have fallen off, right?
Clip attached in wrong direction or the sideplate not in position so the clip could not seat as it should.
I have seen chain with clip missing, sideplate still in place when it cannot be moved without tools.
Good idea to have a spare master link, clip in the toolbox with a small plier, screwdriver.

There is no metal pins, screws sticking out that can interfere with the chain?

[dave500]

the clip is stamped out,itll have a somewhat rounded and somewhat sharp edge one side or the other,install the sharper edge toward the outside,this way the pin groove sees a better flatter surface less likely to glance over and fall off compared to the rounded side which might provide a ramp effect,the same thing is done with circlips the pressure side goes to the best flattest surface of the stamping,also don't stretch or pry the clip open to fit it,youll soften its tension,fit them this way.

[70CB750]

You know that chain tension is set with somebody sitting on the bike, right?

[PeWe]

the clip is stamped out,itll have a somewhat rounded and somewhat sharp edge one side or the other,install the sharper edge toward the outside,this way the pin groove sees a better flatter surface less likely to glance over and fall off compared to the rounded side which might provide a ramp effect,the same thing is done with circlips the pressure side goes to the best flattest surface of the stamping,also don't stretch or pry the clip open to fit it,youll soften its tension,fit them this way.

Good point about sharp side, rounded side!
I think it is too easy to attach it with rounded side outwards which will be not that good as opposite. I think I did it wrong back in the days     today riveted link:(

[lrutt]

ditto having to squeeze the ML together with some sort of vice grip or something to make SURE the clip is fully seated in the grooves. That is oh so important. A new chain does NOT got together all that easy as the orings really need to be compressed. I'd bet that was the issue. You're just lucky it unloaded at the stop instead of 70mph and taking out the cases.

[KJ790]

You haven't clarified whether then master link fell out or not. If the chain fell off of the sprockets and the masterlink was still intact, then it is not a masterlink issue. That would be caused by the chain being too loose (either not set right, stretching excessively, or chain adjuster coming loose and axle sliding forward).

[bjbuchanan]

You haven't clarified whether then master link fell out or not. If the chain fell off of the sprockets and the masterlink was still intact, then it is not a masterlink issue. That would be caused by the chain being too loose (either not set right, stretching excessively, or chain adjuster coming loose and axle sliding forward).

He said he found the ML near the chain, it must have fallen off

[Schnell]

You haven't clarified whether then master link fell out or not. If the chain fell off of the sprockets and the masterlink was still intact, then it is not a masterlink issue. That would be caused by the chain being too loose (either not set right, stretching excessively, or chain adjuster coming loose and axle sliding forward).

He said he found the ML near the chain, it must have fallen off

So that's the problem. Did the master link and clip come supplied by the manufacturer with the chain, or did you buy the ML the shop separately? If bought separately, the shop may have given you the wrong size. If supplied with chain, then you installed it incorrectly. It is slipped on from the side, not pressed on from the front.

[jdubb1977]

yep, the master link came undone.  i did squeeze it on from the sides and not the front, but it's definitely possible that it wasn't fully in the grooves, or maybe facing the wrong direction.

Two questions on my next step

1. can i reuse this chain, given my note earlier about one of the connecting links being stiff since the master link fell out?
2. if i can reuse this chain, should i?  is this chain strong enough for our old 750's, or should I look at something else.  any recommendations on a non-o ring chain?  here's a link to this chain for ya http://www.bikebandit.com/aftermarket-parts/motorcycle-wheels-and-final-drive/chains-universal/rk-m530-h-heavy-duty-motorcycle-chain

[Adam_F]

Stating the obvious... but lucky thing it fell off when stopped rather than going 75 down I-5.  On another note.  I see you're from Encinitas.  I grew up down there.  Great place to ride year around!  I'm sure some of the 750 folks here can recommend some good chains for ya.

[jdubb1977]

Stating the obvious... but lucky thing it fell off when stopped rather than going 75 down I-5.  On another note.  I see you're from Encinitas.  I grew up down there.  Great place to ride year around!  I'm sure some of the 750 folks here can recommend some good chains for ya.

very true!  that would have been a pretty big bummer.  and yep, encinitas is a great place.  year round riding weather, and less than a mile from the ocean.  rough life!

[jdubb1977]

just wanted to ask again...

any recommendations for a good, non o-ring chain?  already broke the bank on a bunch of recent updating, so trying not to do much more damage!

[seanbarney41]

yep, the master link came undone.  i did squeeze it on from the sides and not the front, but it's definitely possible that it wasn't fully in the grooves, or maybe facing the wrong direction.

Two questions on my next step

1. can i reuse this chain, given my note earlier about one of the connecting links being stiff since the master link fell out?
2. if i can reuse this chain, should i?  is this chain strong enough for our old 750's, or should I look at something else.  any recommendations on a non-o ring chain?  here's a link to this chain for ya http://www.bikebandit.com/aftermarket-parts/motorcycle-wheels-and-final-drive/chains-universal/rk-m530-h-heavy-duty-motorcycle-chain

holy #$%*e!  that is a cheap chain!   so it's either a huge bargain(unlikely) or a total piece of crap (more likely)...I think acceptable quality chains start more around $80.  I prefer o-ring variety for less maintenance but I have not been picky about the brand

[bjbuchanan]

For a standard chain you are in the 50-70$ range usually. That is for non o-ring and high tensile

[faux fiddy]

I had this happen, on an old chain. I replaced the clip with a used one off a honds because the one I ordered at the shop was too thick to fit, where the used one snapped right in place.

[jdubb1977]

I was hoping for a great bargain, and think I ended up w/ piece of crap.  Gonna get a JT x-ring from Dennis Kirk and call it a day!

[lucky]

Rear wheel alignment can cause a chain to come off.
Measure from the swing arm pivot bolt to the rear axle on each side . Both sides should be the same. Ignore the stamped marks on the swing arm.

Check the swing arm bushings too.

The front sprocket or splines cam allow the front drive sprocket to wobble and cause the chain to come off also.