pics of crack in frame (Full Version)

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pics of crack in frame

  

thrasher572 -> pics of crack in frame (1/8/2008 11:07:07 AM)

Here is the picture of the crack in the frame. I have found identical cracks in three examples of 87 and 88 hurricanes.

[image]local://upfiles/23095/597C118765274C25A54CFAEED8DCE0FA.jpg[/image]

  
rrasco -> RE: pics of crack in frame (1/8/2008 11:43:48 AM)

interesting, i may have to go outside and check my frame, you guys got me all worried.

thrasher572 -> RE: pics of crack in frame (1/8/2008 11:49:15 AM)

Don't worry it can be repaired. I stripped one bike down to the frame so it could be ground out and welded properly... it is a lot of work but can be done.

rrasco -> RE: pics of crack in frame (1/8/2008 11:55:20 AM)

Haha, what on an F1 doesn't turn out to be a lot of work.  So the bike you bought new was the only one you have seen that was not cracking?  I wonder if the other ones were ever stunted?

michigan_313 -> RE: pics of crack in frame (1/8/2008 12:14:28 PM)

i take it the crack is that vertical fuzzy brown line on the frame?

it looks as though the frame is under some kind of stress causing the frame to be wedged apart. engine vibration is dampened by the frame and suspension. and would not be so destructive as to put a crack in a frame. doesn't even look like a torsional stress caused crack. i have over 90k on my bike and nothing like that has shown up. creepy...


thrasher572 -> RE: pics of crack in frame (1/8/2008 12:16:46 PM)

One of them came to my attention when a newbie rider was trying to trade it off at a local bike shop. It was in overall rough condition so the bike shop gave it a good inspection and found the crack. They informed the owner it was worthless to them due to frame damage. The next move was to call me and ask if I was looking for a parts bike... I was the only one they could think of that still rides a hurricane around here. I bought it for $300.00. I attributed the condition of the frame to poor life that bike had.
The second bike came to my attention when one of my friends who was learning how to ride bought an 88. I have been maintaining it for him and noticed the crack during routine maintenance when we had the plastic off.
The third copy with the crack I found in a consignment shop... I offered to buy it pending an inspection of the frame... it turned out to be cracked too. The plastic was in such good shape that I couldn't pass up the bike and bought it anyway. This bike was babied.
I posted my theory on the reason they are cracking in the other thread...

rrasco -> RE: pics of crack in frame (1/8/2008 12:20:23 PM)

Yeah, I read the other thread.  Just seems to be like that might be a place that could potential inherit a lot of stress when coming down off of a wheelie.  That would be my hypothesis.

thrasher572 -> RE: pics of crack in frame (1/8/2008 12:23:27 PM)

That is why I put the question out there. My original bike has been ridden hard but not abused... no crack.

michigan_313 -> RE: pics of crack in frame (1/8/2008 12:53:27 PM)

wheelie or trying to wheelie would be a good theory. upon the frontend coming down, the forks will compress taking a heavier than normal compression load. the remaining load will be transmitted to the frame, but since the steering head area is heavily reinforced, the next place stress can travel is down the frame spars. so the next weakest part of the frame is the engine plates where it goes from vertical to semi-horizontal. this is a very simplistic explanation but leaves other questions unanswered.


thrasher572 -> RE: pics of crack in frame (1/8/2008 1:18:51 PM)

Whatever is causing the cracks may never be entirely explained... However, it is still a good idea to inspect this area of your bikes frame to see if it is present on your own bike. I have seen it too many times to call it coincidental... this may be my favorite bikes fatal flaw... or an opportunity to pick up cheap parts bikes from people who are unwilling to go through the amount of work it takes to correct it.  In any case, no reputable dealer will knowingly sell you a bike with a cracked frame. The consignment shop where I purchased my last copy pulled it from the showroom immediately when the crack was discovered. There is just too much liability.
My advise is simply to inspect your own bike. The crack will be obvious.  

racerrick -> RE: pics of crack in frame (1/8/2008 7:19:48 PM)

check the vins of the 3 bikes to see if they were build close together. mine with 19,000 miles is clean

ob1w0n -> RE: pics of crack in frame (1/9/2008 1:52:09 AM)

Just checked mine, it's probably about 1/4 of the length of the one thrasher572 posted, but it's cracking at a slight angle (to the left).  Is this something that absolutely needs to be fixed if I'm doing gentle riding?  Maybe somebody with more experience with materials can tell us how likely the frame snapping would be based on a crack like that?

thrasher572 -> RE: pics of crack in frame (1/9/2008 8:18:55 AM)

The engine is solidly mounted in the frame. This engine develops a high frequency vibration that puts your hands to sleep around 5500rpm. That vibration is transmitted through the frame. Ride it below 5000 rpm it is smooth, ride it above 6000rpm it smooths out. 5500 rpm with stock gearing in top gear is approx 60mph. If you or the previous owner have put up with the buzz on the highway at the speed limit (or close) for an extended period that high frequency vibration has to more than put your hands to sleep... Metal will eventually fatigue and I think that is what we are seeing. Early in my riding career I didn't like the buzzy feel at the 5500rpm range so I did a few things to avoid running the enginge at that speed. Drop a tooth at the countershaft (front) and the result is 500rpm higher at 60mph. The other thing was to cruise in 5th rather than 6th gear. Or become a habitual speeder. My frame is intact and it has been under my use and care since new.  I have 3 hurricanes an 87 i bought new , and two I aquired in the last couple of years plus I maintain a fourth one for a friend. The one I bought new is good... The other three have cracks... one repaired. My friend has continued to ride his copy as is. I will end up with that bike when he is done with it and then the repair will be made... until then I am still monitoring it to see if it gets worse.

Gearloose -> RE: pics of crack in frame (1/15/2008 12:28:18 AM)

I've got one frame that is cracked in exactly the same position, and it seems definitely to be a fatigue crack.  I don't know the frame's history.

I have a theory that the crack might be related to (or contributed to by) the engine mounting through bolts not being fully tight.  When I changed the engine in my other frame (which had no cracks!) I noticed that the 2 through bolts weren't very tight.  Also, one aluminum spacer on the LHS (could have been the top one but I'm not sure) was worn, indicating that it had been loose enough to have been rubbing between the engine and the frame. I checked the spacers from the cracked frame, and one spacer was even more worn.  If one or both through bolts weren't tight enough, the frame could flex more, or vibrate more (see Thrasher572's comments on vibration), which might add to the stresses on the mount.  So I'd suggest checking the torque on all the engine mounting bolts (36 ft-lb or 50 N.m), especially the through bolts.

thrasher572 -> RE: pics of crack in frame (1/15/2008 2:50:05 PM)

The bike in the picture has not been disassembled for repair yet... I will check the tension on those bolts to see if they are loose on that one... Thanks for the feedback.

  

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