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Bad Day "Broken Crank"
http://www.kawi2strokes.com/forum/viewtopic.php?f=14&t=4131		 Page 1 of 2
Author:  500trip [ Mon Aug 13, 2012 2:37 pm ]
Post subject:  Bad Day "Broken Crank"
Found a serious problem with my 75' H1 yesterday, and hoping someones heard of this. I found that after it quit running a week ago because of no spark, my ignition pick-ups had broken apart. Further tear down, I've found that the end of the crankshaft had broken off at the crankcase seal, still attached to the stator/armature I guess it's called. Anyone heard of this happening? Also, about 2 months ago I had paid a shop to work on the bike, which that same side seal had been replaced because they said it was sucking air/not sealing. Is it possible that pulling off the armature or removing the seal, (which was mangled after removing) that maybe hitting the end of the crank, or something of that nature to cause a hair line crack or something. Just seams to coincidental being in that area, and for this to break off like this...........or is this caused by age /wear and tear! Thanks for any help in this issue. Talk about ruinning your day!
Terry
Author:  Ja-Moo [ Mon Aug 13, 2012 3:07 pm ]
Post subject:  Re: Bad Day "Broken Crank"
There has been some breakage through the years, but it was probably done by the shop, getting the rotor off, and maybe not a great casting.
Author:  Jim [ Mon Aug 13, 2012 3:09 pm ]
Post subject:  Re: Bad Day "Broken Crank"
There may be a chance that the end of the crankshaft cracked and let the shaft wobble a little, causing the seal to leak.
Author:  rotortech [ Mon Aug 13, 2012 3:28 pm ]
Post subject:  Re: Bad Day "Broken Crank"
Jim wrote:
There may be a chance that the end of the crankshaft cracked and let the shaft wobble a little, causing the seal to leak.

This is my opinion as well. The leaking seal was due to cracked crank not running true in the seal. It was probably a matter of time. Please post a good close up of the fracture surface. That surface will sometimes tell the story of how it broke.
Author:  BarryB [ Mon Aug 13, 2012 5:24 pm ]
Post subject:  Re: Bad Day "Broken Crank"
Sorry for your troubles, but this is why 95% us us work on our own bikes - at least these old monsters and other 2-stroke monsters.

You don't have to be a master mechanic either, not a lot of specialized tools and such. And these things are so easy to work on - even a cave man could do it :mrgreen:

So it looks like a rebuild for you - no problem. Tear it down, find out what's broken, post some pictures, solicit some advice, read up on the manuals and such at MRAXL resource board and rebuild it. You'll never have to worry about what "the other guy" did - ever!

This is your first post - I hope we see more of them.

bb
Author:  scrambler73 [ Mon Aug 13, 2012 5:45 pm ]
Post subject:  Re: Bad Day "Broken Crank"
BarryB wrote:
Sorry for your troubles, but this is why 95% us us work on our own bikes -bb



Amen.

Every, and I mean EVERY time I've paid someone to work on my motorcycle, car, etc, they forget something, lose something, scratch something, dent something, dont do something I paid them for, and on and on and on.

NOBODY cares about your machine more than YOU.

Like Barry says, these things are simple to work on, but there are some "gotchas" that aren't mentioned in the factory service manual. That's one of the reasons why forums like this exist.. Helping other like-minded people keep these dinsaurs alive. :thumbup:
Author:  500trip [ Mon Aug 13, 2012 9:01 pm ]
Post subject:  Re: Bad Day "Broken Crank"
thanks, I'll take some pic's in the next couple of days. I need to figure out how to attach photo's to my site. By the way.........the shop that did some work for me, or should I say: screwed me out of some money and shotty work, was Johnny's Vintage cycles in Wadsworth, Oh. Not a good experience with them. Charged me a lot of money, said it was fixed, gave it back to me not fixed......found on my own that the idleing up was caused by the new (cheap) intake & base gaskets sucking air among other things they were asked to look over and didn't repair. Yeah....I usually don't give in to shops, unless I'm about on "tilt", because I can't figure it out.....which this had me there for a couple months (dumbfounded), but they forced me to tackle it again till I found the problems. What sucks is, I finally got it running good for a few weeks till this.

Terry
Author:  Looney Cylinders [ Mon Aug 13, 2012 9:54 pm ]
Post subject:  Re: Bad Day "Broken Crank"
Have you ever missed a shift/slipped out of gear and had the revs go to the moon? This will either break or bend a crank to fail later. Have a look and see if the crank is rusty in the area of the fracture. Rust pits will cause stress risers/cracks. Sometimes you can see the crack progression of the failure over time with "beach marks" appearing in the fracture surface. That little taper stub is rather small isn't it!.....

J
Author:  BarryB [ Mon Aug 13, 2012 9:59 pm ]
Post subject:  Re: Bad Day "Broken Crank"
I gotta feeling they did not have the right rotor removal tool, banged on it and used the wrong puller - damaged it that way. $20 on-line tool coulda saved it... Lesson learned - now you have an awesome forum for support on how to do it yourself :thumbup:
Author:  Looney Cylinders [ Mon Aug 13, 2012 10:08 pm ]
Post subject:  Re: Bad Day "Broken Crank"
If hammers and chisels were used there will be marks on the case and the rotor. I expect everything would get smashed to pieces before getting the rotor off without some sort of proper tool. Those darn rotor things are usually next to welded on :o

A main bearing may have let go causing an out of true/vibration failure as well.

J
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