subframe issues

hi all,
thought i would throw this out there to get some ideas on what course of action i can take....

'99 ZX9R
where the bottom rail on LHS of subframe joins to the solid frame, has cracked thru the weld. all the way thru. dont know why tho'. so, i had it re-welded, and now 6 months later, its done it again. not all the way thru this time, but i have noticed the crack appear.
will this be an ongoing drama?
the crack is on the subframe and not the solid frame. but the the rail of the subframe had to be welded back on at the join

any ideas/suggestions that dont involve selling the bike?

Pete

Cut the subframe right off, grind down the existing welds, reweld from scratch, unfortunately.

gotta agree sounds like its twisted and its pinging the weak point.

If it's your sub frame cracking at a weld at the same place again it must be getting stress from the main frame it's self! Is the bike a ex-racer or been crashed before. If you carry a lot of weight on the back of the bike (luggage, pillions), how much do you weigh, do you ride it like a motogp bike. Do you accidently wheelie because the wind gets caught under the front fender.........

If your main frame is twisting enough to crack the welds on your sub-frame check it out asap. Take the tank off and rear sub-frame and check all the welds you can see on the inside. Check above and below where the rear shock is.........don't be surprised if you find a hair line crack in the main frame somewhere that is letting the bike twist enough to crack the sub-frame where it bolts to the main frame. Let us know if you find something!

snr

Did the original repair include removing the frame and preparing the joint properly before rewelding?

Pete
Like I said on Saturday, you really want to take it to Laurie Alderton, I believe he is the best frame guy in Sydney...
Laurie Alderton Mechanical Repairs. (02) 9609 2889
2/10 Long St, Smithfield, NSW

and check out these goodies to fix up that rearset..

http://cgi.ebay.com.au/Kawasaki-ZX6-ZX9 ... dZViewItem

thanks Dave,
i'll look into it.