General Discussion Anything SuperHawk Related

Presenting.... ye broken crank

Old 05-30-2015, 08:34 AM
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Presenting.... ye broken crank

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Old 05-30-2015, 08:36 AM
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Holy smokes batman!!!!
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Old 05-30-2015, 10:17 AM
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I'm no metallurgical scientist officer guy, but, well, there's your problem!

Wow, really cool looking. Sorry it happened to you Micky.

Just look at how that came apart. Did half snap cleanly and the other half rip apart?
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Old 05-30-2015, 10:26 AM
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I just noticed the small hairline fracture on the counterweight side of the journal.... wonder if that's where it began?
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Old 05-30-2015, 10:48 AM
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Originally Posted by CruxGNZ View Post
Just look at how that came apart. Did half snap cleanly and the other half rip apart?
couldn't tell you, I wasn't in the engine when it happened, lol
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Old 05-30-2015, 12:08 PM
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A metal fatigue analyst might enlighten us to what could've happened. Do we, ah, possibly have one of those guys on this forum? Might be a long shot.
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Old 05-30-2015, 12:32 PM
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It will buff out sweet as.....
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Old 05-30-2015, 01:16 PM
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Is it worth contacting Honda to see if they would be willing to analyze it.
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Old 05-30-2015, 01:41 PM
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Looks like, according to the beach marks, it held together better than half way through.
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Old 05-30-2015, 02:55 PM
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Originally Posted by CrankenFine View Post
Is it worth contacting Honda to see if they would be willing to analyze it.
That would be nice, but I think I can hear laughter all the way from Japan.
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Old 05-30-2015, 08:24 PM
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JBWeld gentlemen, it works every time.
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Old 05-30-2015, 08:39 PM
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Maybe show it to Roger Ditchfield. He may have some contacts who can help.

James
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Old 05-30-2015, 08:53 PM
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Originally Posted by Wolverine View Post
JBWeld gentlemen, it works every time.
pretty well what I was thinking. Reckon I will keep the new crank as a spare......
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Old 05-30-2015, 08:58 PM
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So....did I miss it or what was the lead up story to this awful disaster? You were minding your own business, and then......
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Old 05-31-2015, 08:11 AM
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Originally Posted by smokinjoe73 View Post
So....did I miss it or what was the lead up story to this awful disaster? You were minding your own business, and then......
...Micky told a joke about Nantucket, and his crank cracked up
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Old 05-31-2015, 08:47 AM
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Originally Posted by CruxGNZ View Post
...Micky told a joke about Nantucket, and his crank cracked up
I should have listened to Mum.... she had warned me against Nantucket jokes......
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Old 05-31-2015, 09:07 AM
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It's because he used the wrong oil.... And his tire pressures were WAY off....

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Old 05-31-2015, 09:14 AM
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I've been trying to tell everyone the rotella is, well you get it now I suppose!
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Old 05-31-2015, 10:19 AM
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methinks I'll never really get to the bottom of what happened (though some things are coming to the fore, like improper bearing selection during the previous rebuild), but I can guarantee you it's not the oil's fault (quite the opposite in fact)......
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Old 05-31-2015, 01:00 PM
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Describe in detail events leading up to the above photos and consequential damage to the engine...

Inquiring engineers want to know...

Watching the RA SS race now though.
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Old 05-31-2015, 01:08 PM
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Not much to say. Bike was running fine, I pulled over on the side of the road to make a some small adjustment to my Flo-Commander. I killed the engine and when I restarted it, it was making a terrible racket from the bottom-end. End of story.
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Old 05-31-2015, 04:46 PM
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Originally Posted by mikstr View Post
Not much to say. Bike was running fine, I pulled over on the side of the road to make a some small adjustment to my Flo-Commander. I killed the engine and when I restarted it, it was making a terrible racket from the bottom-end. End of story.
The second part of my question was "consequential damage to the engine?"

What was maximum and average rpm engine was typically run up to?

Do you commonly rev up and then cut the throttle on the over-run with engine braking?

How much heavier are / were your oversize pistons than OEM?
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Old 05-31-2015, 05:10 PM
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as I did not take the engine apart, I have to rely on those that did, and their take is that everything else is fine (again,m it happened at low speed/idle, which is likely what prevented further damage of course).

as for my use, I ride on the street (no track) and work hard at keeping my driver's license, so I mostly ride in the mid-range. 99.9% of my riding occurs in the 3k-7K rpm range. The engine has very seldom been revved above that while riding (though it has been on the dyno quit a few times). I do decelerate with throttle, but again, nothing abusive. I take very good care of the bike and warm it up properly before riding it. I don't do burn-outs and that kind of nonsense as my goal is, and will always be, to make it last and ride it in a respectful manner (considering the money I have invested in it, I want it to last). Oil changes have always been regular (@ 2.5K miles typically) with good quality oil (used Motul 5100 a lot, along with Rotella). Break-in after both rebuilds was long and methodical, with frequent oil changes to carry out the shavings and other crap.

as for the weight of the pistons and rods, the (forged) pistons (despite being 0.5mm oversize) were lighter than the OEM bits, same goes for the rods. Also, the crank was balanced for the new parts, so I dare say the balance factor is closer to optimal than the way it rolled off the assembly line.

In short, I fail to see how anything I did can be responsible for this happening. While I am not an engineer, I work in the powersports industry and spend a fair amount of time around, and discussing with, engineers. This does not make me infallible by any means, but it has given me a good understanding of sound operation and maintenance practices. Take it from there......

Last edited by mikstr; 05-31-2015 at 05:13 PM.
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Old 07-27-2015, 06:11 PM
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I hope Mikstr won't get mad about this, since I didn't ask him his consent. Anyway, part of the healing process is to talk about it.

Mike broke his crank due to the fact it wasn't very well done the last time. Perhaps not directly because of lack of knowledge, but, perhaps they didn't understand what kind of vehicle they were dealing with.
Anyway, more harm than good was done to it, rendering it much worst then if nothing had been done to it and left stock.
The crank comes already balanced from Honda at a pretty good level. You could install it without touching it, and you're good. Below is a pic of the broken crank, and all of the holes that have been made to it in order to balance it with the special rods/pistons Mike has in his engine. They basically mist the target. With all those holes, it is perfectly balanced for.....3000rpm's

Just cruising on the highway with stock gearing, you're at 4500rpm's at 120km(70mi). Imagine how much stress was on it when revved up to 7-8000rpm's !!!

So, this is what not to do if ever you find yourself replacing your crank.

Presenting.... ye broken crank-100_0593.jpg
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Old 07-27-2015, 06:48 PM
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no anger here bro... demz da facts........
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Old 07-27-2015, 11:10 PM
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Originally Posted by Jack Flash View Post
Mike broke his crank due to the fact it wasn't very well done the last time. Perhaps not directly because of lack of knowledge, but, perhaps they didn't understand what kind of vehicle they were dealing with.
Anyway, more harm than good was done to it, rendering it much worst then if nothing had been done to it and left stock.
The crank comes already balanced from Honda at a pretty good level. You could install it without touching it, and you're good. Below is a pic of the broken crank, and all of the holes that have been made to it in order to balance it with the special rods/pistons Mike has in his engine. They basically mist the target. With all those holes, it is perfectly balanced for.....3000rpm's

Just cruising on the highway with stock gearing, you're at 4500rpm's at 120km(70mi). Imagine how much stress was on it when revved up to 7-8000rpm's !!!

So, this is what not to do if ever you find yourself replacing your crank.


I wrote it before on UK forum, I came to the same conclusion when installing my lighter pistons. Theoretically new balancing should be done, practically there is nobody around doing it properly (dynamic balancing for whole group, to proper specification), so it is much safer to left it as it is from factory.
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