Frame Cracked Under Seat

[autopilot]

Two causes in my opinion.

 

I'm sorry, but I'm thinking design deficiency is partly to blame. There is a huge moment arm (lever) created with a pivot point essentially at the weld, by all the mass (what ever it happens to be [bike parts, passenger,etc.]) from that point rearward. Looking at Cougar's pics, the location and weld looks to be incredibly awkward even for robotics. They don't look well thought out either. (looks almost like butt-welds, which would NOT be a choice for that location, IMHO. Pieces could also have been mal-positioned for welds, creating a stress-riser at the weld sight. [kinda like leaning into a punch- a knock out waiting to happen]) Shoot, it could've been a bad piece of tubing!

 

Secondly,

Repeated loading within the guidlines under nominal road/riding conditions would likely never show up, even with the welding and stressors present, as I'm sure Yamaha's testing confirmed. However, my opinion is that this damage is not necessarily due to repeated overloading over time. Were that the case there would have been indicators on any bike of similar design--ie, all of them. Yes, I feel substantial overloading was involved. But, I also feel that this was a catastrophic "shock" type of impulse force to the frame section; as in the previous rider/passenger got momentarily airborne with the bike and the landing shock load was just too much for it.

 

These sorts of things usually would have something in the range of 200+% safety factor for strength designed in, so if one assumed design & weld were ok, then the frame took a hell of a shock load to do that.

 

ALL things considered, while the design at that spot leaves something to be desired in my opinion, empirical evidence tells us that these bikes are overloaded regularly and sometimes substantially, without incident. Therefore, the only logical conclusion is that this is a one-off happening for reasons we probably won't ever know with any certainty! Who fixes it is anybody's guess.

 

OK, my brain's empty now so, I'm going to excuse myself!!!

[Gary N.]

When I tie my bike down in the trailer, I use the braces under the back of the rear fender and cris-cross the straps to keep the rear tire from hopping around. Does anyone think that by maybe pulling too tight at this point it could put enough stress on the frame to cause this crack? Or possibly using another point as a tie down spot and over tightening could have caused it? Just thinking out loud. Sometimes this gets me in trouble though.

[autopilot]

Gary, I don't think two people together could apply enough force even with leverage to cause that kind of damage with tiedowns.

 

 

One slight modification to my dissertation as regard stress over time even with normal loads. I happened to recall my '79 Corvette. I bought it used, thought I had checked it thoroughly enough. NOT! It had been in a substantial wreck that required the lower control arm attachment to be re-done. Somebody botched the job and the mal-position of the pivot points on the lower control arm was enough to cause the mount to literally tear itself out of the front lower crossmenmber, bringing part of the crossmember with it. I was having some work done and my mechanic called me, I went and looked and it was literally within 1/8th of an inch of tearing out of the cross-member completely. So, if the pieces were mal-positioned, it could happen over time due to over-stress at the weld.

 

 

DMooch, If you're getting flex while riding and you obviously have something approaching 1/2 inch space sitting still...then without this end fixed in place, you are applying that moment arm (leverage) somewhere else, to some other component that shouldn't be seeing stress like that. Somebody told me one time.... "You don't push a bad position". (probably when I was in a fight, getting my butt handed to me on a plate)

 

OK, I'm done again.

[Gary N.]

Gary, I don't think two people together could apply enough force even with leverage to cause that kind of damage with tiedowns

 

I don't think it could be the problem either but what's happening when the rear of the bike is tied down like that and the trailer hits a bump? The suspension on the bike is working and pulling tighter on the straps and being pulled at the back of the bike it could exert a force like a lever on that part of the frame under the seat. Again, just thinking out loud. I've pulled my bike a lot of miles tied down that way and don't think it was a problem. Pretty sure my cracks were caused from the accident.

[DMooch]

Thanks of course for everyone's input, whether someone else thinks it's valid or not. My main reason for posting was (1) to see if anyone else had ever heard or seen this kind of break in this region and (2) help others keep an eye out for a POSSIBLE failure on their own bikes.

 

As far as I know, the bike was 100% original with no impact accident damage at any time, other than having evidence of a fall over to the left side by the previous owner (scratches on fairing, left mirror, clutch lever) but no major frame problems. Any inspection I did before purchase was detailed, knowing especially to look in this area for battery acid corrosion, and I had the opportunity to do so because they installed the new battery while I was checking it over.

 

As for any noticeable trunk bounce I mentioned, it was only if I was on an especially bumpy road, but I also mentioned I ride into NYC sometimes (not known for the smoothest roads). Again, no trailer, and it's never been trailered by me (I ride it bike events, not trailer events!).

 

I've seen pictures of plenty of couples easily tipping the scales more than my wife and myself riding two-up, with I'm sure plenty of matching luggage and travel gear. How many here can HONESTLY say they don't go over the 400 lb. limit Yamaha says the bike can carry? Remember: that's people AND luggage AND gear. If there's a 20 lb. limit per trunk and saddlebag, that means you and your mate better not tip more than 300 together, and add in your clothes and helmets, to push that limit!

 

The bike hasn't been ridden since the beginning of December, so it has sat for a few months. Gravity will work over time, and once both sides broke completely, that's when the sagging began. There's two other support points on each side for the rear sub-frame, and I've checked those too (all tight). The gap you see may have been expanded due to me moving the rear end around checking for that possible looseness elsewhere, and taking the pics afterward. When initially discovered, the gap was about 1/8" on either side, and I was barely able to get the cable tie in the area back through and in place as shown in one of the pics I attached.

 

I agree it is a poor design in this area. That broken-off piece should be a tube that slides into an opening on the main frame, not a butt weld, to make a stronger joint, so I am on the same page here with autopilot. A welded area has no flexibility in it and will always remain rigid (except in this instance), as such any shock to the area whether from road surface, bouncing passengers and luggage, to other impacts will stress that location. The bolted on parts have a minimal amount of movement allowed in them because the 3 pieces (part a, part b, fastener) involved are all still physically separated even though attached at a common point. Which is why I think the saddlebag stays and the other mounting points for the fender and sub-frame are still doing their job since any transmitted force was absorbed by them where as the weld didn't fare so well.

 

If I HAD NOT LOOKED CLOSER at this, looking at the bike assembled, NONE OF YOU would have ever thought there was a break in this part of the chassis. It still fits together THAT GOOD overall. Besides, at least two of you have actually inspected your bikes just to be sure...

 

On the more hopeful side: I have made contact with a few persons in the area of welding skills (I can do just about anything mechanical, but have no weld-ability), and they will be looking at the bike Sunday or Tuesday, depending on availability. Opinions will be offered and received on the task at hand. By phone, all feel it's fixable, but of course a personal inspection will make the true determination. If it's a go, I'll be stripping the rest of the parts off the back and sides of the bike (fender, sub-frame, side covers, wires, hoses, battery & case, etc. etc. etc.) and the fuel tank (no fires!) so that a full-circle weld can be done. I'll also run the bike dry after I pull the tank to empty the fuel line and pump as much as possible.

 

Seriously, too: I was intent on selling the bike this year and moving to something lighter, as previous knee and hernia surgery keep me off this fine bike more than on it. Any takers?

[Brake Pad]

First: I'm not that fat. 225 lbs. No passengers on bike in some time. 35k miles on the bike's odometer. Garage kept, but not temperature controlled, on Long Island, NY. Now...

 

While re-installing a freshly charged battery into my 99 RSV, I noted that both sides of the frame are cracked completely through in the piece that the rear tab of the driver's seat would go into. This piece also has two bolts that go into the rear fender, essentially providing almost all the support for anything over the rear tire (rear seat, trunk, saddlebags, etc.). (See attached scan from parts diagram; I can hopefully take and attach an actual image of this part on the bike another time.) I also noticed the beginning of a 'kink' in the right side of the rear fender, apparently due to the stress of the saddlebag support pieces having to carry all the weight from above.

 

Has ANYONE here had this happen to them? Or heard of other's in a similar situation? I'm kinda bummed about the riding season starting real soon and the possibility of no bike for an extended period of time until this is fixed. Plus, I just sent off the insurance premium and registration fees.

 

Welding recommendations (type, process, who can do it)? Difficulties involved (other than getting the fender and related parts off)?

 

 

look at this:

Wikipedia encyclopdia

I looked up Electrical Arcing, look up the work cathode

It says a battery can produce a electrical arc-read up on it.

I looked at your pictures, and the only thing I can think of that would snap the frame apart is electricial current

just maybe the battery at some point ARCed

[autopilot]

Gary,

I agree with you about the suspension , but only to a point. You've got both the trailer and bike suspensions (bike to a lesser degree due to tie-down) taking up the jounce & rebound, so I still don't believe that could cause or contribute to it. I stick with my original assessment. A poor design for sure, but I believe a singular problem limited to this bike.

 

 

DMooch,

I think you're being too polite. I've seen couples without counting bag & trunk contents doing better than.........Let's just say I know guys that are 275-300 by themselves!

We owe you a big thank ya, sir, for being the discoverer of this potential problem. If it is present in other ventures, I for one vote that the fix carry the name of it's discoverer. "The DMooch Weld"!! Has a ring of sorts!!

 

 

Brakepad,

Sorry, man, I can't get there from here. (A) There's no evidence of arcing. (B) The metal in the pics is physically torn apart in tension. © In my experience, I can see no feasible way, electrical arcing could be the cause or even a contributor.

[SaltyDawg]

It's possible that a previous owner who was rather large had the shock failure and didn't fix it . The continued bottoming out of the bike along with the heavy rider could put stress on those points. The reason I feel this is possible is that I am heavy and when my shock blew the bike bottomed out so hard a couple of times that it broke fillings out of my teeth.

 

Not saying that is what happened, but it is one thought.

[autopilot]

Forgot all about the shock problem. That could absolutely be the culprit. I think it would take several good licks or a couple really substantial hits under a heavy load. You would get the exact kind of force application necessary to do the type of damage present. The question is: What combination of weight and shock loading (force not shock absorber) would do it!

 

This would be a neat problem to solve in the lab. Ahhhh! This has been invigorating. I haven't devoted this much brain time to solving real problems in years. Short of actual experimentation, I think we've done all we can here. As long as some of this stuff helps DMooch get resolution to his situation, then it's OK!!!!

 

Color me gone!!

[tazmocycle]

i have done a lot of welding of many differant materials, and it looks like this is a stress break. this is seen a lot in cast welding, where the parts being welded is preheated, welded and then slow colded. if the parts are welded without being preheated, the stress caused by the weld will pull the welded materal just below the weld joint. this weld could have been made too hot causing it to be brittle and after cooling down caused it to break.. i would take it to yamaha dealer and let them look at it, that way it will be noted by them and if others are found to be breaking at this point it you may get a refund for your repair costs. i think it would be a good idea for as many members check this out closely to seeif this is just a fluke! any good welding shop should beableto fix ths break and maybe add a t-shaped brace to add strength to it.

[BuddyRich]

Don't know a lot about welding. But it does look like that's a stress point from the rear seat and trunk. The rear fender frame mounts (#12) to the upper section of that and then bolts to the lower part of the frame. That would act like a pivot for a lot of weight on the rear seat and trunk. We may all want to check that area from time to time just in case its a bad design. If its a bad weld then maybe its an isolated problem with just that bike.

 

http://parts.yamaha-motor.com/partimage.gifx?d=96906,4,0

[Freebird]

This is a great thread and is sure something that everybody needs to check on their own bikes. Most of my riding, at least on longer trips, is two up and pulling a trailer that is usually loaded heavier than it should be. I just went out and inspected my '99 and it looks fine. I can see no cracked paint or any other signs of stress. If I see any other reports of this happening though, I will be looking at a way to reinforce that area.

[Cougar]

Don, I think this would be a good thread to add

to know problems or to keep it a sticky some how?

 

Just so folks can keep an EYE on this... just a thought.

I am like you always two up riding and trailering..

Jeff

[Steve S]

DMooch

 

I found a breakdown of the frame in a parts manual. The rear fender support bracket is bolted with 2 bolts below the break and one bolt ABOVE the break. If there was a stong downward force applied to the rear fender supports, that could cause the seperation shown in the pictures. The way this frame is made, that seems to be the only way that bracket could have enough force excerted on it to pull it apart.

 

If someone before you tied the bike down using the fender supports, or across the back seat, or WAY overloaded the trunk and passenger seat, several hunderd pounds overloaded, it could have caused the metal to crack. Then it just seperated under normal use.

 

After looking at the design of the frame and the pictures of the break, I cannot help but believe that the bike was severely stressed when this happened. That doesn't mean that it was abused, It was just stressed beyond it's ability to withstand the punishment. Properly welded back and properly loaded this will continue to be a wonderful ride for you.

 

Just my 2 cents worth.

 

RIDE SAFE

[Guest Saddletramp]

Would it be possible that when the bike itself was tied down to a trailer that the trailer could have flexed enough to have pulled the bike apart. I am thinking that if the bike was pulled tight to the carrying vehicle and the carrying vehicle was flexed or even damaged to where it was moving and stretching could this pull the bike apart?

[DMooch]

To all: WELDING IS COMPLETED.:cool10:

 

Other items mentioned:

I replaced the shock with the updated model in 2005, and I run it with about 25 psi on a regular basis. (I prefer a stiffer ride.)

 

I never trailered the bike, so it's never been tied down across the back end in any way by me. Prior owner, kinda doubt it, since he traded it for a Wing in '04, and I know of no Wing rider that trailers anything except behind their bikes. (General observation.)

 

Battery arcing? No evidence of it at all (melting, scorching, etc.), so that's not possible.

 

As for mounting points, there's a few more than I realized. The two in this broken piece, the one srstewart mentioned (which I knew), plus the little bracket that acts like a wire loom and is the bolt location for the rear saddle also goes into support #12. While this last one doesn't do much, it is still there. And then there's the fender side supports which aren't shown in the frame diagram.

 

However, this morning I loosened up every part in the area, removed the battery tray and all other non-metal items. A friend-of-a-friend has a MIG welder, and he came over this morning, assessed it as do-able, and did it. A few test welds for strength yielded good results, so full-circle welds on both tubes were done. Nice thick bead all around, much more than Yamaha originally supplied. I will paint over it once cooled, and then reassamble the entire works as time allows during the week.

 

Oh, and a good whack with a hammer after the welds were done verified a good bond. No movement at all.

 

BEST PART: $0.00 = FREE repair

 

And while "The DMooch Weld" is nice, I can't take the credit for that work. The damage or break maybe, but not necessarily the actual fix.

[Cougar]

I am so happy for you that this all came back together...

Very Cool!

 

 

Jeff

[Guest Saddletramp]

Good to know that the frame has been repaired. I guess it will remain a mystery as to what truly caused the break. Good luck and keep an eye on the area of repair.

[Guest tx2sturgis]

I just got in on this thread...I cant believe that you guys all missed the actual cause of that break....Blue Lights! I saw the pic of the broken bike with the blue lights...and everytime I see blue lights in my rearview, it has caused a HUGE amount of stress!

 

[tomfromhull]

Hey SaltyDawg, I think you're on to something.

[Steve S]

DMooch.

Glad to hear that you got the bike fixed. Personally I dont believe you will have any more problems with it. It had to have been a situation where everything just worked together just right to make that happen. I hope you have many miles of fun out of her.

[DMooch]

To all: Repair Pictures Attached

 

I took a couple of shots of the repaired area. Much more welded material in the joint now, as you can see in the unpainted shots. After a few swipes with some generic black touch up paint, you can barely tell any work was done.

 

Soon enough (Tuesday afternoon, I'm hoping) I'll start re-assembly. Shouldn't wind up with any spare parts afterward, wondering "Now where did I pull this off? Where was it supposed to go back?"

[Brake Pad]

just thinking.....

are your holes going to line up now?

[Freebird]

You will probably never have another problem with it. Glad it turned out to be a quick fix for you. I sure would like to know what caused it but we may never know.

[DMooch]

Brake Pad: Holes will line up fine. Doesn't look like they will, but the piece is in the exact same position and place. It appears way off because the rear fender and sub-frame assembly was loosened to allow for proper welding, so it is still misaligned at this time.

 

Freebird: It may very well remain a mystery... But as I said before, some owners have already checked with negative findings, and I'm sure there's plenty of folks on here that will make this a regular (if at least seasonal) check over that gets done on their bikes before any lengthy ride.