Rotten GS550 swing arm. Any ideas?

[Animal Mother]

I'm stripping down a 550M to turn it into a cafe racer.

Sadly, I've discovered that the swing arm is rotten/rusted through on the plate near the pivot.



Is there a direct replacement or (simple) upgrade or would I just have to repair or replace with the same one?

[JEEPRUSTY]

Replace it
lots show up on ebay.

I wonder how in hell that could rust like that. Was it used as a boat anchor?

[ronin1166]

I wonder how in hell that could rust like that. Was it used as a boat anchor?

IIRC, that's area where the battery vent tube exits.
My guess is battery-acid attack; crummy reg/rect was overcharging/boiling the battery.

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[Animal Mother]

I'm in the UK. We use salt on our roads.

[Animal Mother]

There's one on ebay. Will a 650 or 850 arm fit?

[Ghostgs1]

Isn't your bike a chain drive?

[Animal Mother]

Isn't your bike a chain drive?

Yes. Oops. They're shafties aren't they?

[ronin1166]

An 8-V 750 or 1000 arm might fit...?
Or possibly 16-V 750?
Some measurement involved.

8-V 550s were built in decent numbers. I'd think you could find one fairly easily.
Spares situation may be different in the UK, though.
Good Luck.

BTW - what's an "autojumble"? Seen that term in a few Brit mags, just curious.

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[Animal Mother]

Horror!

Right. I took the swinging arm off today.

Unbelievable! I'm surprised the guy didn't crash and die.






There's a replacement on ebay (UK) but I don't think I could trust it.

What else fits?

How about:
GT750
GT550
GT380
GS750

[ronin1166]

HOLY CRAP!

PO rode with a horseshoe in his pocket...

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[allojohn]

If the swing arm is in that condition you'd better have a very close look at the frame!

[Animal Mother]

If the swing arm is in that condition you'd better have a very close look at the frame!

It'll be getting blasted before coating so that should show up any nastiness.

[ronin1166]

Good idea...trouble is, they are bare, unpainted steel inside the tubing.

I recently saw a thread on another board of a newish Ninja 250 frame that just collapsed one day...rusted through from inside...looked fairly normal on the outside.
Definitely something to consider.

http://pnwriders.com/motorcycle-talk/154240-bike-disintegrated.html

I live in the NW USA...not called the Pacific Northwet for nothing! Rains here, a LOT, similar problems as you UK boys.

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[Animal Mother]

Good idea...trouble is, they are bare, unpainted steel inside the tubing.

I recently saw a thread on another board of a newish Ninja 250 frame that just collapsed one day...rusted through from inside...looked fairly normal on the outside.
Definitely something to consider.

http://pnwriders.com/motorcycle-talk/154240-bike-disintegrated.html

I live in the NW USA...not called the Pacific Northwet for nothing! Rains here, a LOT, similar problems as you UK boys.

.

Other than the failure that frame looks great.

I'll make sure I give it a good going over.

[haztoys]

BTW - what's an "autojumble"? Seen that term in a few Brit mags, just curious.

.

Auto ...motorcycle swap meet to us Yanks .............As for the rust on the arm ... Very comman here realy