Aluminium Frame Repair Yamaha TZ250.

[Brad93]

Got a repair to do on an YAMAHA TZ250 (I think that's what it is). It's a bit of ali box to the casting that houses the shock and swingarm bearing. The original weld (25+) years old has cracked half way round. I'm planning on grinding out with a deemed and carbide tip, then rewelding with 4043, as it is on to a casting.

Does this sound about right?

 

[Brad93]

Will get some photos tonight but I need to repair it for the guy tonight ideally as he wants to race again this weekend.

 

[HMB]

Should be ok. Clean clean clean

 

[Richard.]

Little tip I do for quick removal of an Alu weld is centre dot it every 10 mm and with a Drill then drill into it So far on every centre dot to form a track. Then you use your carbide burr to dress it up.
A carbide bur alone takes ages and often doesn't go deep enough. I'll dig out a pic to show if I can find one.

 

[Richard.]

Here's one. Very similar case to yours. It cracked from a bolt been over tightened near it. Then someone had a bash at welding it with out digging the crack out and it cracked again. I took it right out with the drill then tracked it out with a burr. It didn't help the other welder had run over it with a grinder after welding so it was very contaminated. This photo shows half way through my prep. Once done it was a smooth track with about 1MM of material left.
Very carefully on the pedal I got a full pen weld. I'd of been there forever with a burr alone.

 

[Richard.]

Oh and obviously be very careful not to drill through it

 

[Chris Stevens]

Have repaired quite a few trials and MX alloy frames, and found that if repairs done with 4043, sometimes cracking occurred again. Use 5356 now and no further problems..............guy who used to work for Spondon advised that filler.

 

[Richard.]

I've repaired lots of castings and if it's a an Alsi material then using a Alsi filler is more likely to be successful. on a 7*** series frame would I use a 5*** filler.

 

[Jim Davey]

Alu cut burrs gouge a groove very nicely but they are expensive for one off jobs. Well worth the money if you are tackling this stuff on a regular basis though. Good tip on the drill though Rich, I'll be stealing that little idea...

 

[norlander]

Oh and obviously be very careful not to drill through it

no problem, just tell the customer its a stress relief hole.

 

[Richard.]

no problem, just tell the customer its a stress relief hole.

It's true mind. Drilling a through hole at the end often stops cracks in there tracks.