Holes in Frame

Greetings to all and Happy Holidays!

I am in the process of reassembling my '99 YZ400F after a complete teardown. I have the main frame on the bench after a good power washing and cleaning up all the rusty spots with the wire wheel.

The wire wheel turned up a few spots in the frame that need attention. One spot is the foot peg mounting plate that's welded over the frame tubing. The right side has what appears to be three rot holes.

The other holes in the frame are also pretty rough. These are drain(?) holes from the factory. There are a number of other holes with VERY shoddy welding done such as under the subframe mounts and in between the shock link mounts.

My question is what are these holes for? What damage could occur in the future should I weld these holes closed? My subframe was powder coated by a previous owner and is in excellent shape but it has no holes in the tubing like the main frame does.

You will find two small holes on the bottom of the cradle, and probably also on the sub. These are to allow air in/out of the tube during the welding process. You can close them, but whatever moisture is in there will remain there.


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