Cracked Frame

[CRboy167]

I have a 98 YZ400F and I have developed a hairline crack in the frame between the steering stem and the oil filler neck. Anyone ever repaired anything like this before?? Thanks for any information

 

[flynbryan]

Should be as simple as sanding away the paint and putting a weld on it. Some one correct me if I'm wrong.....

 

[JasonJ]

Hmm, you should maybe take it to a pro welder. That is a very stressed frame section and its also part of the oil tank. It should probably be Ved out and then welded so the oil tank should be drianed and youll have to watch if you grind it out that shavings and all dont get into the oil tank.

 

[yz250-effer]

Mine broke there - not all the way up the stem, but halfway on my 01 250F. I had to bite the bullet and get a new frame - it was too far gone with cracks all the way back near the near the triangle part of the frame.

Definitely take it to a proffessional who knows how to weld that particular compound of steel.

 

[motometal]

i'm guessing that's 4130 alloy steel tubing. if i'm right about the material, to do it right the frame should be pre and post heated or it could crack after welding. This procedure could be difficult due to the unique situation of having much oil residue on the back side of the area to be welded.

Without knowing Yamaha's procedure for stress relief, etc. it's hard to say if the frame would be as strong after the procedure.

 

[Ol'89r]

Originally posted by motometal
i'm guessing that's 4130 alloy steel tubing. if i'm right about the material, to do it right the frame should be pre and post heated or it could crack after welding.

This is correct if it is tig welded. The area to be welded has to be pre-heated and after welding it must be heated to a dull red in color. If it is just a small crack, you could vee it out and wire weld it and wouldn't have to stress relieve it. Arc or gas welding is not recommended.

If properly done, it will be just as strong as stock.

Just my $ .02

Ol'89r