Broken Frame 2010 YZ450F

[KJ790]

You never know, it is actually a huge problem in certain industries, it's one of the reasons my job exists. I never really thought about it when it came to bikes, but it is always a possibility I suppose.

[grayracer513]

Unfortunately, it would be too destructive a form of analysis in most cases, but it would be instructive to look at some cross cut sections of those welds. I'm leaning toward inadequate penetration and/or embrittled (shielding, etc.) or insufficient fillers.

[FZ1426]

Dang! This made me go out and pull my airbox to look!

It occurs to me the first question Yamaha Motor Corporation would ask if questioned as to liability in these cases is: Did you modify the frame or engine in any way? and, Did you torque the engine mounts to the the frame per the torque specs in the manual?

The other thing I question (in addition to how many hard landings are involved) is engine to frame torquing procedure. There is an optimum engine to frame sequential torquing procedure involved that allows for proper tension and (un)loading of the frame. Basically the upper spars need to flex. The '11 Yamaha manual lists a sequence although it is not clearly explained other than it is expected you'll perform each step in the order that they're printed. The headstay should be the last thing that gets torqued.

I could see a situation where if the engine was hanging (or supported) in the frame and the headstays were tightened first, then the swingarm and lower mounts, it could stress the spars, especially if there was other damage (or modification) to the frame.

I always tighten the the other engine mounts first, then the headstays to the frame, then the headstays to the head.

Edited November 28, 2012 by FZ1426

[gbalias]

im still curious about the blackened areas.

[dirtjumpordie]

I would just use se aluminum flat-rod and hose-clap it to the frame like a splint.. Works for me on my 1997 cr250 in open A supercross and AA harescrambles that I win twice a week

Edited November 27, 2012 by dirtjumpordie

[rider-99]

im still curious about the blackened areas.

I looked back at some pictures before I disassembled the bike and the black marks are from the coating on the wiring. Also, I normally wash it with purple power. I am also guilty of not checking the torque of the motor mounts. They were all tight with the exception of one. It wasnt about to fall out or anything, just wasnt tight like the others.

Edited December 4, 2012 by rider-99

[dirtjumpordie]

I would re-inforce the area around the weld when you fix it. I can't imagine that the stressed-out aluminum around the crack is very strong either. Should have got a 2 stroke by the way

(I just like to throw that in there)

[MarkDan]

So has anyone called yamaha yet to see what they say about the cracks. I just tore down my bike and found one small crack, then quit looking cause I didn't want to be anymore depressed.

[Benloos349]

Have you guys always kept up on motor mounts, subframe, and swingarm bolts being tightened to spec? My kx frame broke because motor mounts got loose and the structural integrity of the entire frame was gone.

[KJ790]

I looked back at some pictures before I disassembled the bike and the black marks are from the coating on the wiring. Also, I normally wash it with purple power. I am also guilty of not checking the torque of the motor mounts. They were all tight with the exception of one. It wasnt about to fall out or anything, just wasnt tight like the others.

The two things that stand out at me are the loose motor mount and using purple power to wash the bike. Purple power is very caustic and very corrosive to aluminum. If any of that got into a weld and sat it could definitely be a bad thing.

[gbalias]

The two things that stand out at me are the loose motor mount and using purple power to wash the bike. Purple power is very caustic and very corrosive to aluminum. If any of that got into a weld and sat it could definitely be a bad thing.

i know this may be a long shot, but what are you guys (cracked frame folks) using to clean the bike?

some cleaners are known to have adverse effects on certain alloys.

id have to agree. that stuff is potent

Edited December 4, 2012 by gbalias

[Chazmagnum]

On a possative note. I just checked mine and it looks perfect! Whew! I am a 250lb plus guy TOO! I have blown out 2 sets of head bearings from hard landings. Broke my leg from hard landings. I have 92hrs on my 2010 and NOO cracks. I DO follow the torque procedure also. I only ride tracks also. Looking forward to 2014, hoping for a few tweaks (slimmer up front).

[rider-99]

I did blow out my steering stem bearings a few months ago. I came up really short on a double. Is this a comon problem?

[vic2340]

My friend races quads ( steel frame) however his stock frames crack all the time. He tells me once you properly gusset the welds there is practically no chance in them breaking at all. Dont even worry about finding a new frame. the one you have can be made twice as strong than a new frame if put in the correct hands. ?

[jnabuurs]

I have a question to all YZ450F riders with a broken frame "what kind of fork springs do you use in front and rear I mean how stiff (kg/mm).

[76_ride]

Is this a common problem with the 2010-13 model

Or is this just an isolated?? On the market for a

New bike reading this thread has made me think

Again about the YZ450f..

Edited December 10, 2012 by Seventy76six

[grayracer513]

It's not common, it just happens to a small percentage of heavily thrashed bikes, as far as I can tell. There were a few cracks around the steering head reported on '07's, and I think I've heard of an '06 that cracked, too. But the "problem" isn't exclusive to Yamaha or aluminum frames. There have been steel frames posted on this forum that cracked, too.

Normally, not too many of the people whose frames have never cracked feel terribly inspired to post about it.

[76_ride]

Been doing my head in trying to find any info on this matter, spoken to a mate who works for yamaha said they've never heard of this happening. Buying a new bike, got my heart set on the blue bomber but serious thinking changing colours now.

[KJ790]

From what I have seen it is a very rare problem. I have a friend that is a pretty good pro. A few years ago he was on a Suzuki team and he told me that they would replace their practice bikes every couple weeks because the team riders were cracking so many frames. Last year he rode YZ450's for Star Valli Yamaha and he never mentioned anything about frame issues like when he was riding Suzuki's. If anyone is going to find weak frames, I would say pro's like that who put tons of very hard time on these bikes would be seeing the issues first.

[jnabuurs]

I inspected a lot of YZ450F and never seen one with a cracked frame from 1999 to 2012.