Widening alloy swingarm?

I need at least a few mm more width on the driveside of my swingarm just to centre a ZX9 wheel. If I could widen it just 1/4" overall it would make things a lot easier for both centering and mounting the caliper bracket. I spread a steel swingarm about 3/8" using a car jack, wondering if the alloy arm will spread 1/4" before cracking if pressure is applied/increased a little over a few days? I've seen a number of aluminum frames bent but not cracked at the wreckers, got me thinking.
Any ideas, suggestions?

it would be really hard to keep things square without cracking it unless you were to heat it up a little,but that might weaken it also depending on what kind of aluminum it is.got a picture of the swingarm?

wireman wrote:

it would be really hard to keep things square without cracking it unless you were to heat it up a little,but that might weaken it also depending on what kind of aluminum it is.got a picture of the swingarm?

The hub been machined as much as possible, so the only option now is to open up the swingarm a bit. Machining a few mm off the eccentric and trimming the swingarm would do it but I really don't want to remove material there, it would be removing a bit from the welded joint.
Here's the only pic I have showing the swingarm.

Hey Fossil - If I were you I would take the swingarm to a good machine shop that works with specialty metals. They will tell you if it can be done without causing any stress cracks.

It doesn't cost anything to get an estimate and they might even give you some ideas on how to do it yourself. When it comes to an expensive part like a swingarm, I wouldn't take a chance on breaking it through experimentation.

Cheers-Colin Firth-Ontario Canada

do you have enough clearance everywhere besides the adjuster,or does the whole side need to be moved out?if you had access to a good heli arc and a welding table where you could clamp things down nice and square without moving it could be mitre cut in a couple spots and bent like a box ofset in a piece of conduit and welded back together i suppose;)

Fossil wrote:

I need at least a few mm more width on the driveside of my swingarm just to centre a ZX9 wheel. If I could widen it just 1/4" overall it would make things a lot easier for both centering and mounting the caliper bracket. I spread a steel swingarm about 3/8" using a car jack, wondering if the alloy arm will spread 1/4" before cracking if pressure is applied/increased a little over a few days? I've seen a number of aluminum frames bent but not cracked at the wreckers, got me thinking.
Any ideas, suggestions?

Problem solved - just bought a brand new ZZR1200 swingarm with axle, adjusters, pivot bolt and chain guard for $143 shipped - a "buy it now" on ebay. And, it's in Canada too so I might see it this week.

pic and dimensions - very close to the GPz, similar linkage and wide enough for the 5.5" ZX9 wheel and 170 tire.

cool,thats cheaper than modifying your stock one!