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88 Alternator removal (busted drive chain)

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  #1  
Old 08-25-2018, 11:03 PM
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Question 88 Alternator removal (busted drive chain)

So I remove the 3 alternator cover bolts and lightly taping the 11 o clock area and the 2 o clock on the cover, it came loose and I could move it a little left/right due to the wire harness. Then I figure to remove the 3 mounting bolts so to be able to move the alternator a little more left/right so to tap the 10 o clock are and the 3 o clock area on the cover.
Then it happened the alternator started to slide out the engine case, so I pulled on it and out it came shaft nut, bearing, damper, drive sprocket, and clutch all in one piece :O, is this normal? . So I took it to the bench vise and pulled the cover and drilled a small hole on the center of the cover for lubing to make thing easier next time. I wrapped the busted drive chain on the sprocket and clamped it down on the bench vise, that sucker was tight, seems like it had more than 36 ft lb on it. Anyway clutch works good and the damper looks great, no damage on the sprocket, so far so good .
I am thinking that the original alternator shaft nut installation torque procedure may be stressing the alternator starter chain by holding the crank and then turning the nut to the spec 36 ft lb , any coments ?
Time comes for me to install the alternator back in and torque the shaft nut, I am going to torque the nut trough the alternator by
turning the nut under the outer alternator bearing, good idea or bad?




 
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Old 08-27-2018, 02:14 PM
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Originally Posted by jaimenv View Post
I am thinking that the original alternator shaft nut installation torque procedure may be stressing the alternator starter chain by holding the crank and then turning the nut to the spec 36 ft lb , any coments ?
Time comes for me to install the alternator back in and torque the shaft nut, I am going to torque the nut trough the alternator by
turning the nut under the outer alternator bearing, good idea or bad?
There's a ratcheting chain tensioner bolted to the inside of the upper crankcase half, so I don't think you'd be able to damage the chain - at least if you were tightening it that far, you'd probably already have shattered the crankcase itself. I didn't have any trouble with it, except that I had to guess the torque since there wasn't enough room to get a torque wrench on the alternator shaft nut

Do you have the crankcase apart yet? I'd be curious to see some pics of the damage. Any idea what caused the chain to break?
 

Last edited by tentacleslap; 08-27-2018 at 02:51 PM.
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Old 08-27-2018, 11:16 PM
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Arrow Fun with torque wrenches and chains

Originally Posted by tentacleslap View Post
There's a ratcheting chain tensioner bolted to the inside of the upper crankcase half, so I don't think you'd be able to damage the chain - at least if you were tightening it that far, you'd probably already have shattered the crankcase itself. I didn't have any trouble with it, except that I had to guess the torque since there wasn't enough room to get a torque wrench on the alternator shaft nut

Do you have the crankcase apart yet? I'd be curious to see some pics of the damage. Any idea what caused the chain to break?
Hey thanks for replying to my post.
Correct me if I am wrong but it looks like the tension on the chain while tightening the alternator drive shaft nut will be at the bottom part of the chain not the top.
Then looking at the way the chain is made it has flat link stock instead of round, unlike regular chain. it looks delicate to me.
You would need a torque wrench similar to this one to do the job and yes you will need a 6 point 14mm wrench end extension.

More info at this link https://www.workshopaddict.com/tools...urable-torque/
It's going to be a while before I crack her open due to me having back and left hip problems(thank god for turmeric/curcumin) it will not be good for me to wrestle around a 100+ lb engine. I am going to build a overhead hoist frame, so to lift the bike off the engine and lift the engine to a bench.
I am also curious to see if any other damage occurred.
The guy that sold me the bike said he heard like a pinging sound once he turn the engine off it would not start again (starter turn engine won't).
He said he park it in 2016 or there abouts before the big storm (maria), so supposedly it sat for 2 years + before I got it, due to a divorce.
The alternator on this bikes is quite large, figure that trying to pop wheelies and burn outs will accelerate chain wear to the point it fails.
I would like to hear if any one out there had the alternator drive chain fail even when they baby or granny ride the bike.

 
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Old 08-28-2018, 01:03 AM
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Yeah the long block weighs closer to 200 pounds if I recall. Even with the heads and cylinders off it was uncomfortable to move around

I would think that being attached to the sprockets means the chain would bear a smaller amount of torque (ie the opposite of leverage, as it would act like an increasing gear which would reduce force at the larger radius) but if you're worried, recall that the factory would have done it the same way

As I say, I'm interested why it failed. When I had mine apart I remember thinking that the alternator chain was way beefier than any of the other driven chains. I figured it would be the last to go. It's made up of layers of hardened steel plates, the same as the timing chain, and pretty typical for the application afaik. Compare that to the oil pump chain which looks like it should be used for bicycles

I don't know of a lot of people who end up snapping them. Even if the engine's been abused, we'd probably expect to see failures elsewhere. Probably worth searching the forum to see if anyone else has had a similar problem
 
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Old 08-28-2018, 11:19 AM
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Unhappy Busted chain pictures

As I say, I'm interested why it failed. When I had mine apart I remember thinking that the alternator chain was way beefier than any of the other driven chains. I figured it would be the last to go. It's made up of layers of hardened steel plates, the same as the timing chain, and pretty typical for the application afaik. Compare that to the oil pump chain which looks like it should be used for bicycles

Yea I agree the chain in the alternator drive is beefier, so there must be a reason for this guess there are some dynamic loads going on that the honda engineers deem the need for the larger chain. At any rate in the spirit of trying to figure out what happened here are some pictures of the busted alternator drive chain.


 

Last edited by jaimenv; 08-28-2018 at 11:23 AM. Reason: try to add another picture
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Old 08-28-2018, 12:08 PM
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Whoa, that's a cool failure. I mean obviously it sucks to be dealing with, but wow

It looks like a sudden localized failure. I see damage to a couple other links, but I'm guessing that happened after the first failure caused the chain to lose alignment. Looks like the links snapped right off. Did the riveted pin shear, or are we dealing with a possibility of improper installation? Maybe a manufacturing defect?

Hopefully the rest of the block's okay. I bet there's some twisted metal in the sump but would think the strainer would have blocked the large chunks this thing would have thrown off
 
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Old 08-28-2018, 03:01 PM
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Arrow Another busted chain picture

There is no riveted link on the chain, if it had it maybe that's where the failure occurred. It looks like the chain was factory built to length.
If you look closely at the busted links you can see that the link pins are made up of what looks like a hollow piece with a flat center pin that extends to the chain links. why they did not use round link pins is beyond me.

when I get the new chain I will check it for a riveted link pin.
Before I bought the bike I did a little research and new that this could be the reason for the bike not starting, didn't wanted it to be, but it turns out it is.
Also there is no fun on a quick fix .
Another thing is the tensioner is there and it springs back when pressed and released trough the alternator mounting hole.
 
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Old 11-05-2018, 10:00 PM
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Thumbs up Splitting crankcases, the new pramary chain is in


Here are the damaged parts, The ratchet locking thingie failed on the primary chain tensioner. Wonder if it was defective or something caused it to break the serrations to the point it will not hold adjustment.
Note the groove in the tensioner and the slider looks like it ran like that before the chain binded and broke, maybe the same force that messed up the tensioner busted the chain at the mark (arrow).
 

Last edited by jaimenv; 11-05-2018 at 10:06 PM. Reason: more inflamation
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Old 11-05-2018, 10:14 PM
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Engine looks awesome inside hope after all this I get to at least ride the bike around the block . Sorry for the blurry picture guess I need a shot to steady the camera.
 
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Old 11-08-2018, 05:15 AM
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Interesting post this one.
Ive not delved into the bowels of the cbs I once had, but done most other things.
Have a close look at the broken links, and do they look as though they have been stretched, as I m wondering if maybe a foreign object found its way between the sprockets and the starter chain. Have you taken off the sump to see if anything is floating about.
Alternatively it could just be a one off failure, and put down to bad luck. Those chains though are a strong construction and I recon would take quite a hammering before they break. You only need one hardened pin to break out of the countless ones in that chain to snap.
keep us posted.
 
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