My 1977 KZ750 Chain BROKE today while I was riding

JWKZ750 wrote: I have a question. Im trying to determine if this is human error that caused the chain to fail. My mechanic put new tires on the bike last week. A day later this happened. How can i be clear on what caused chain failure....him or the chain?

I'm with Ed on this: cheap chains are going to be their own ending. Perhaps the stress of the wheel removal and subsequent re-tightening of the chain put it over the top? I'd put my money on that.

JWKZ750 wrote: I have a question. Im trying to determine if this is human error that caused the chain to fail. My mechanic put new tires on the bike last week. A day later this happened. How can i be clear on what caused chain failure....him or the chain?

It is possible that the chain was not properly adjusted, and if the proper amount of slack was allowed it would put undue stress on it. However, the chain shouldn't break. It's also possible that the master link was not attached properly or was facing the wrong way and that could cause it to fail. However, there is no way you will ever know if there was human error or not.

If you plan to keep the bike you really need to use the Kawasaki Service Manual and learn how to properly adjust the chain and perform other normal maintenance tasks. That is the only way you can be sure maintenance and repairs are done properly. Ed

This is exactly what a friend told me, and this is exactly what I intend to do, take care of my own bike.

If it did indeed have a half link, that wasn't the proper chain for that bike. Some guys will "cheap out" and buy a industrial chain. Rather than looking to attach blame, I'd buy the best I can get and RIDE THE PISS OUT OF IT.:woohoo:
There are three bearings. The set I bought (all balls) didn't list the third one. They came as a kit and all three were in it. Be sure it has the seal as well.
Steve

I looked at all balls and since it only showed two in the listing, I went to Bike Bandit and they charged me $20 per bearing on 3 bearings. I didnt know ALL BALLS had three in the packet. Im annoyed now loil

You may be able to save the seal; by driving the old bearing out from the inside.
steve

JWK, I've been riding and wrenching on my own motorcycles since 1968. I learn something new all the time. Read all you can and listen to those who have been there done that. It doesn't take long to figure out who knows what they are talking about.

I figured out a LONG time ago that all drive chains are not created equal.....and pretty much you pay for what you get.

I've made the mistake and set up my gearing incorrectly and had to go with an odd number link count and have had to use the half links. I've had two fail. Correctly adjusted, aligned and lubed.......BOTH of them were caught before the chain came apart because I kept a close eye on them. To be honest......I still have the bike and it still has a half link in the chain. The manufacture of the chain I use now rates the strength for the half link at half the rating of the chain itself. This one has lasted a couple of years and a few thousand miles. BUT, I'll get around to regearing it someday back to the even numbers and do away with the half link.

I do believe the main cause of my two failures is that the links were generic links. I finally found a chain company that matched a half link to one of their chains and that's what I'm using now. But it took awhile to find it.

The reason your chain had a half link???? Who knows??? mismatched sprockets???? or.......an attempt to get more miles out of a worn out chain ( yep, ive seen it done) ....somebody takes a link out thinking that will fix the out of adjustment condition......only to find out the chain is now to short......hmmmmmm "maybe if I add one of these". You'll probably never know.

Some of the best advise is to learn how to do your own work.......but not everyone likes working on these things.

Take care, Gordon in NC

By the way, with respect to replacing the wheel bearings in that hub... that snap ring can be a mother bugger to get out without the right snap ring pliers.

Im having my mechanic deal with the job. I dont have the time, but after this im going to jump headfirst into repairing this bike myself.

I don’t know if your mechanic is a motorcycle guru or if he is totally unfamiliar with bikes, but I see that you haven’t got the time to do the work yourself. However – you must certainly have the time to at least check the amount of slack in the drive chain when your mechanic is finished since this will take no more than 3 minutes.

For instructions on performing this extremely simple task look at page 17 at:

www.kzrider.com/modules/ServiceManuals/K...l%20KZ750%20Twin.pdf

If you are too busy to at least check the chain slack I would highly recommend not riding the bike until you can find time to do so. If you find the chain slack is not set properly I would urge you to find another mechanic or let the bike sit until you have time to perform your own maintenance. Keep in mind that when problems happen while you are riding a bike you can get very seriously injured. Ed

In my opinion if the guy saw the half link and said nothing, he's not the one I would have work on my bike.
Steve

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