St1100 swing arm. The Achilles heel!

[Nickcrl]

Ok had a blow on my exhaust on the last MOT so decided to strip bike down and remove the exhaust. Typically one job can often lead to another.
I thought I have got this far I may as well take the swing arm off and have a look as it’s common for these to fail.
well! For only 43,000 mile on the clock and the bike being registered in 2000 I didn’t expect quite what I found. The swing arm was absolutely rotten. They are silly money to buy new so figured sod that I’ll repair it myself. Sent it to the shot blasters and although it looks good believe me it was rotten s
So I rebuilt the swing arm. I’ve heard you cannot rebuild these? You can if you know what your doing.
believe me when I say this doesn’t look like much but it took me 5 hours to rebuild. All gaps and open seams have been welded up I will drilla few holes so I can wax oil the internals. It’s now in the powder Coaters for a zinc primer powder base coat and black finish coat.
mum glad I stripped the bike down now. Wheels have also gone for powder coat too!
whilst the bike is basically part stripped down I’m going to change the cam belt as its 23 yrs old. The clutch doesn’t grab until the last minute to changing the clutch as well!

 

[Erdoc48]

Good job! The rotting of the swingarm really isn’t a thing here in the US (mostly in the UK) due to more substantial use for commuting, I assume more salt spray in the air, etc. in the UK, whereas here, they’re more like recreational vehicles, for pleasure use and little use in the rain and elements.

 

[Nickcrl]

A few predictive text mistakes grrr! Not mum. So

 

[Nickcrl]

True! Parts of the USA are fair weather and warm but! Parts of the USA are more like the Uk also. East coast Midwest etc I believe salt is used on the roads too!

 

[klaproth]

Well done! Looks like you’ll get another 23 years out of it!
Maybe more , since you are doing such a complete job on it. The wax oil is a great idea.

 

[ST1100Y]

... have a look as it’s common for these to fail.

Common??!
It's the location & usage...
You've mild winters, hence ride year round, so the brine on the roads (plus the fact that you blokes just HATE washing yer motorcycles... ) ruins everything and conditions them rigs like been on the bottom of the ocean for decades...

And FWIW, I wouldn't bother with welding, besides already compromised metal integrity that swing-arm will warp like a slice of pepperoni on your hot pizza without being clamping it a proper jig during the job...
Locate a good, low mileage one at a breaker, treat it with Waxoyl (or other quality cavity protection wax) and install that one...

 

[SMSW]

well! For only 43,000 mile on the clock

With those miles I'm surprised you might need a clutch. More likely will be the clutch slave cylinder and a good flushing. Maybe even check the clutch hand lever pivots/bushings.

that swing-arm will warp like a slice of pepperoni on your hot pizza

Pepperoni, huh? Good thing you don't like anchovies, the metaphor would be awful to behold.

 

[Upt' North]

Nick, the clutches all grab at the same point, but it can be made worse by the brass bushing in the lever wearing due to lack of lube. It's the Bush that the pushrod operates on.
Good catch on the swingarm.
Upt'North.

 

[Andrew Shadow]

True! Parts of the USA are fair weather and warm but! Parts of the USA are more like the Uk also. East coast Midwest etc I believe salt is used on the roads too!

The difference being that in those areas people generally don't ride in the winter, or at least not when the roads are in such condition that ice melting media of some type is on the roads. It is also usually much colder during the winter months in those areas than it is in the UK, so motorcycles see less miles during those road conditions than the UK bikes do, so as a result less corrosion.

What you see in the way of corrosion on UK bikes is what used to happen to cars around here. The bodies would rot from the road salt used in winter. Decades ago it used to be common to see cars that looked like Swiss cheese with all the rust holes in them. The automobile manufacturers mostly figured that one out and it is not common to see anymore.

 

[Hound]

You can if you know what your doing.

I can if I know what my what's doing?

Nice repair. The ST1100's swingarm and collector box always suffered in the UK. I was glad when Honda sorted those issues out with the 1300.

 

[Uncle Phil]

I think they must put acid in the stuff they spray on the roads over there.
I've got loads of miles on my ST1100s, ride year round, and do not have any swing arm problems between the four of them.
Of course, we seldom get much snow anymore, just ice.

 

[SMSW]

The automobile manufacturers mostly figured that one out and it is not common to see anymore.

Ahhh, but the road guys have learned, too. Now they use brine laced w/ sugar (beet juice?) to make it sticky. My auto mechanic says the ice melting stuff is 'hotter' than just plain rock salt and he is seeing more and more corrosion on the bottom of cars.

 

[Andrew Shadow]

Ahhh, but the road guys have learned, too. Now they use brine laced w/ sugar (beet juice?) to make it sticky. My auto mechanic says the ice melting stuff is 'hotter' than just plain rock salt and he is seeing more and more corrosion on the bottom of cars.

We aren't that fancy here. We just salt the heck out of everything.

 

[rwthomas1]

Ahhh, but the road guys have learned, too. Now they use brine laced w/ sugar (beet juice?) to make it sticky. My auto mechanic says the ice melting stuff is 'hotter' than just plain rock salt and he is seeing more and more corrosion on the bottom of cars.

I believe "brining" the roads started in the Midwest, but its become common here in NE as well. It is most certainly more aggressive than previous products. We have a 2016 F250 at work that will need a frame very soon. Its not uncommon to see 5-7yr old vehicles with bubbles and perforation. I have taken to oil undercoating every vehicle in an attempt to keep it at bay.

 

[SMSW]

I believe "brining" the roads started in the Midwest, but its become common here in NE as well. It is most certainly more aggressive than previous products. We have a 2016 F250 at work that will need a frame very soon. Its not uncommon to see 5-7yr old vehicles with bubbles and perforation. I have taken to oil undercoating every vehicle in an attempt to keep it at bay.

I've been joking for a long time that our community, which has been promised by the mayor to have only 'wet roads' in winter, spreads 1" of salt for ever forecast inch of snow.

But the corrosion is no joke. Does oil displace water or does water displace the oil? WD40 says it displaces water, but it is a lousy rust preventative, and that is, after all, advertising hype. I've avoided the oil spray because it is so messy - no place to park the car for a week or two while it drips oil.

 

[rwthomas1]

I've been joking for a long time that our community, which has been promised by the mayor to have only 'wet roads' in winter, spreads 1" of salt for ever forecast inch of snow.

But the corrosion is no joke. Does oil displace water or does water displace the oil? WD40 says it displaces water, but it is a lousy rust preventative, and that is, after all, advertising hype. I've avoided the oil spray because it is so messy - no place to park the car for a week or two while it drips oil.

I tried Waxoyl. OK for interior spaces but lousy on exterior, it washes off. Fluid Film is better, washes off less but still only stays on for 6months or so. NH Oil Undercoating, so far this is the best. Still present after a year on the underside of vehicles and has stopped the existing rust entirely. Yes, messy but I haven't had it dripping off the vehicles despite heavy applications. It works. There is a new product PB Blaster Surface Shield that appears to last even better than NH Oil. May try that next. I have access to a lift so coating the Suburban is easy. The smaller cars I do on ramps. Tyvek suit and the correct application gun make it much, much nicer. My buddy coats his plow trucks and they don't show any new corrosion. A messy couple hours per vehicle every Fall is a small price to pay compared to the large price of new vehicles or bodywork.

 

[huntingdog]

It is a good idea to make a shield ( mudguard) out of plastic that goes over and down the swingarm, it will protect it and the gas tank from water and grime hitting them all the time.

 

[Taffy]

A few predictive text mistakes grrr! Not mum. So

Oh my days, I laughed out loud reading this. I thought, oh how sweet he still lives with his mum!!!! I'm still laughing. The number of times I have sent texts without checking autospell - it's impossible to imagine how A. I. comes up with some of the predictions. but also as funny as heck.

Nice job on the swingarm. I cheated. I bought a new one as mine was not so holey but universally pickeled by rust! Although, I believe, alot of these can be fixed, and very safely, (sheesh we used to repair everything when we were poor...), I think most of us just can't be arsed anymore, as time, out ON the bike, is more import to what little time we may have left to live. Still putting mine back together as I write. Happy days!

 

[jrp]

 

[ST1100Y]

Yeah, got one sitting at home... never installed as I expect the flap will rub through the metal coating...