What to do about a crack in my frame

Gentlemen, I seek your advice as more knowledgeable individuals with regards to my bike. While going over it to assess what I might need to work on for the pre-season, I came upon a crack in the frame. It looks to me like some sort of burst, though I concede to a more attuned mind. You can kind of see from the bolt, that it is just above where the headers come into the exhaust (for relative frame location with regards to the bike) and the approximate size.

I know it will need to be fixed, but I humbly ask for your opinions or insight into whether this has happened to anyone, if it is a critical fail, and also how much will be involved with repairing it?

 

I had as similar issue that I noted when I was first going over my Seca project. It is likely freeze damage. Water can enter the frame tubes form the rear and collect at the bottom. If the bike is left in freezing conditions, it'll cause a burst.

You can read my experience with it here.

Since I was going through the bike for the first time, and didn't have a trailer, I removed everything off of the frame, tossed it in the back of my car and found a competent welder.

 

I agree, freeze damage. Not got any experience with it personally but I can't see it being too hard to repair, disconnect battery/tci etc, take paint off around it & grind a V to aid weld penetration then weld up & grind back to profile is how I'd envisage the repair being done...

 

That's exactly what I've done for others

 

Provided that you are competent with a stick or MIG unit, I'd recommend dremeling out the crack to clean up the thinnest parts (at the split, where the rust is, drilling a small hole at each end of the split, and then laying a cut piece of tube over the affected area, with an extra half inch or more outside of each end.

Weld it up, clean it off, prime, paint, boom. structurally sound.


I've welded a lot of minibike, dirtbike & bicycle frames with similar damage. Prep work will be crucial for this.

 

+1 on drilling the holes once you've found out how far the split goes, take back to bare metal at least an inch on either side of the split, the drilled holes will prevent the split from continuing. Thought a competent welder will know that anyway

 

Let me take a sec to make a point here about prevention:

This happens when water becomes trapped in the frame and then freezes.

Yamaha frames have little drain holes, and "gaps" in the weldments, etc., all over them to allow any possible trapped moisture to get out. (Muffler "cans" have drain holes too.)

If you maintain your bike and keep it clean, carefully inspect it periodically and keep all those drains clear you can prevent this from happening. But if you let the bike stay grubby/dirty/oily in its nether regions it's easy for those drain holes and gaps to become clogged and then water can get trapped.

 

On a stress/fatigue crack I couldn't agree more with drilling stress-relievers & plating it over, but personally in the area of the frame that this freeze split has occurred I wouldn't think it necessary (and if the crack itself is welded up then there's no need for holes either because the crack no longer exists, as opposed to leaving the crack and plating over it)

 

Perfect, thanks all for the insightful and extremely helpful responses. Quick too. Also thanks Bigfitz for the tips of prevention. I'd picked the bike up last season and never got a chance to fix it up and ride as I had planned, so it ended up having to wait until this season. I'm making more progress now, but then come across things like this. :?