GSXR Motorcycle Shifter Bracket Rebuild (Aluminum TIG build-up)

[jakeru]

I repaired a broken shift lever bracket on a GSXR motorcycle today. The upper cast aluminum bracket broke off cleanly when the owner laid the motorcycle down.
Attachment 1371

I prepped it for welding by grinding the fractured surface and old threads (and a little paint around the edges) down to fresh metal with a carbide burr. I also added a sheet metal heat shield to protect the grease-laden chain and plastic chain guard behind the area to be welded.
Attachment 1372

Then I built up fresh, solid aluminum using TIG (using as much as 200 amps, with no pulse, and about 65-70% EN AC balance), using up a good length of a 1/8" 5356 filler rod. The trick I find on a "long distance" build-up operation like this is to take your time and do it in as many layers is is necessary, allowing the work to cool in between layers to maintain control of the shape. If you don't try and get too big of a blob molten all at once, you can control the final built-up shape with some precision. I also had my digital calipers set up and locked at the desired distance I needed the material to be built up to, which allowed me to quickly check progress of the build-up operation and know when I had added enough material.
Attachment 1373

Then I got out a new aluminum-specific 4.5" grinding wheel and using my angle grinder, tried that out to surface the front face of the built-up material down flat (and in the plane the bracket needed it to be. The aluminum-specific grinding wheel worked very quickly and effectively! It left a smoother surface than I would have guessed and also worked very quickly without loading up. (Like a flap disc does on aluminum.) Here is what the aluminum grinding wheel looks like:


Then it was just a matter of lining up the bracket, scribing where the hole needed to be drilled, drilling and tapping the hole squarely. I tried using pam as a tapping fluid and I found it worked really well, didn't need to re-apply it once. Best tapping fluid I've found for aluminum so far.

I would have cleaned up around the outer edges of the built-up area with a rod-shaped carbide burr I've got that would have made it look as if it were CNC machined, but the customer didn't seem to care much about cosmetics in this area of the bike (and wanted to save a few bucks), so I skipped it as he instructed me to.
Attachment 1376

The lower bracket was bent in a little bit from the crash, so I used a crescent wrench and baby sledge hammer to persuade it back out just a little bit. It didn't take much. Overall the repair worked out quite successfully in the end! Customer was happy.
Attachment 1375

Here is the shot of the bike after being repaired. It looked pretty fast. The customer had it tricked out with some fancy aftermarket stuff too.
Attachment 1374

[worntorn]

would that be a Suzuki GSXR?

[jakeru]

Thanks worntorn, I removed the reference to kawasaki from the OP. I guess I'm more of a car guy than a motorcycle guy.

Your stainless egli vincent build looks great by the way! Never seen a bike like that before, with no frame member below the engine.

[Ram48]

Nice repair.
Thanks for the pictures. Where did you get the grinding disc for Aluminum?
Being a Sait disc I am guessing a body shop supply house. Id like to get a few of those.
Ray

[dirtyfarmer]

[QUOTE=jakeru;8009]

Then I got out a new aluminum-specific 4.5" grinding wheel and using my angle grinder, tried that out to surface the front face of the built-up material down flat (and in the plane the bracket needed it to be. The aluminum-specific grinding wheel worked very quickly and effectively! It left a smoother surface than I would have guessed and also worked very quickly without loading up. (Like a flap disc does on aluminum.) Here is what the aluminum grinding wheel looks like:


About those discs, why don't they load-up? Are they filled with a hard wax or something else?

[ScratchStart]

I have found sait discs at both airgas and fastenall, though the fastenall ones are more pricey.

Great job on the fix. you can't even tell it is there once the bracket is bolted.

question on cast aluminum. Is it any different to weld than a regular aluminum piece?

I know steel and cast iron are very different. just never worked with cast aluminum.

[everlastsupport]

Jackru,

Off topic a tad. But I use wax on the band saw blades for aluminum. Might try PAM and see if it keeps the teeth cleaner. Candle wax works OK.

Nice repair. Hope the rider has better luck this time around, though, if that's all the damage they had good luck last time too. I thought you meant GXSR too, now we know GSXR is a Kawasaki. No longer a bike guy either, esp. those kind of bikes.

[cmd]

Jackru,

Off topic a tad. But I use wax on the band saw blades for aluminum. Might try PAM and see if it keeps the teeth cleaner. Candle wax works OK.

Nice repair. Hope the rider has better luck this time around, though, if that's all the damage they had good luck last time too. I thought you meant GXSR too, now we know GSXR is a Kawasaki. No longer a bike guy either, esp. those kind of bikes.

crotch rocket prefixes:

Suzuki is GSX-R
Kawasaki is ZX
Honda is CBR
Yamaha is YZF

[worntorn]

Jakeru said "Thanks worntorn, I removed the reference to kawasaki from the OP. I guess I'm more of a car guy than a motorcycle guy.

Your stainless egli vincent build looks great by the way! Never seen a bike like that before, with no frame member below the engine. "




thanks

and good looking fix on the bike BTW

[jakeru]

Nice repair.
Thanks for the pictures. Where did you get the grinding disc for Aluminum?

I actually put a link to the place I got it from in the OP, but it seems the link is "hidden" (you need to hover your mouse over the text with the associated link to find the link) due to some funky setting with the new forum. (Maybe we can fix that setting, to make links associated with text more visible.)

Here is the link again (hopefully not hiding behind any text this time):
http://weldingsupply.securesites.com...20062||1|744||

About those discs, why don't they load-up? Are they filled with a hard wax or something else?

Looking at the material of the wheel, I can't tell much difference from a standard (ferrous metal type) grinding wheel. They are both "porous" looking, and generally dark/black color. Perhaps this wheel is more porous than average, but I'm not sure.

In actuality, after using it I did find a few globs of aluminum "loaded" onto the face of the wheel, but apparently it wasn't severe enough to impede its ability to rapidly grind on aluminum.

When I was using it, I felt as soon as the wheel made contact, a good bit (more than usual I'd say) of material was coming off of the wheel (and perhaps large sized pieces being released.) So perhaps the abraisive grains are designed to release / wear down more quickly than your average wheel. So perhaps the main difference is the aluminum-specific grinding wheel is designed to wear down quickly.

FWIW, here is what the marketing literature says (from the above link):
"A46N - Aluminum. Aluminum oxide grain. Soft bond for aggressive removal of material without loading. Outlasts competition by as much as 40%. Non-ferrous metals: aluminum, copper, brass, etc. Specifications: Max RPM - 13300. Tech Info: Special aluminum oxide formulation prevents "loading" on soft (non-ferrous) metals."

Great job on the fix. you can't even tell it is there once the bracket is bolted.

question on cast aluminum. Is it any different to weld than a regular aluminum piece?

Thanx. Biggest challenge welding a cast aluminum part like this IMO, is not knowing what the metallurgy really is due to all the different alloys that could be used for "objects that look like cast aluminum" (including some that are not even aluminum: magnesium and zinc/pot-metal). You can use some info to make an educated guess. For example, how hard is it when you scrape it with a file? The alloys used for casting can also be different than those found in wrought or extruded aluminum, for example on a die cast part (you can often identify whether a part coming from a metal mold, if its surfaces are very smooth and detailed) you may encounter "hypereutectic" (very high silicon) alloys. Hot cracking when welding can be a concern if the wrong filler rod is used, and can be a concern with other alloys regardless of what filler rod is used (referred to as the "non weldable" alloys.) Another challenge can be dirty cast parts, if there can be oils or other contamination trapped inside that is hard to clean out. When welding aluminum, any contaminates with the element hydrogen (including oils/greases, AKA "hydrocarbons") can cause porosity (hydrogen bubbles) in the solidified aluminum weld bead. Hydrogen is highly soluble in liquid/molten aluminum, but not in solid/cooled off aluminum.

Off topic a tad. But I use wax on the band saw blades for aluminum. Might try PAM and see if it keeps the teeth cleaner. Candle wax works OK.

Nice repair. Hope the rider has better luck this time around, though, if that's all the damage they had good luck last time too. I thought you meant GXSR too, now we know GSXR is a Kawasaki. No longer a bike guy either, esp. those kind of bikes.

The bike had a couple bent fasteners I pointed out to the owner, he'll have to replace as well, but yeah the bike fared pretty well, it seemed like the foot shifting mechanism took the brunt of the damage.

FWIW, I found that spray-pam really helped hacksaw aluminum more easily, so one would think bandsawing would work well with it also.