Unfortunately any repair will require a major amount of parts removal. First remove any electronic components that may be damaged by eddy currents generated by welding. Clean the area to re repaired of all parts that might interfere with access to the area to be repaired. Take it to a machine shop along with the part that will be installed after the repair.
Faster and possibly cheaper; get a different frame from a salvage operation - powersportsnation.com is the first one that comes to mind.
Personally, I would just report it to my insurance company and accept the salvage value offered or pay the deductible and let the insurance company pay to have it repaired.
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