ST1100 swingarm (again...)

[Hissnspit]

Good morning and a happy new year,

This is my first post on the forum and I'm afraid it's another swingarm restoration question:

I'm in the process of replacing the exhaust on my 1100 and thought it a good idea to check the swingarm at the same time - no point scraping out the nice new cans just because the rear wheel has fallen off!

With the exhaust off and after some serious squirming around on the ground, it became clear that the swingarm, though still boasting some token paint, is rusting underneath with the paint flaking off to the touch. So, I bought The Tool for removing the left-side pivot bolt locknut and was planning to strip it out today when it occurred to be that I don't know what I am aiming to achieve by doing so.

It was my intention to hand it over to a local media blasting company before getting it welded up if required and, finally, powder coated. Is this the way to go?

Would a coat of epoxy paint work as well (I've read that it is preferable to POR-15 due to its flexibility)?

What to do about the interior rust which, in reality, is surely the bigger problem?

Do I need to bother at all - there are no visible holes in it at the moment?

Okay, I confess. I'm clueless and would really appreciate some input from the wise and experienced members of this forum who have likely been in the same position themselves!

Thank you in advance,

Mark.

 

[ST1100Y]

It was my intention to hand it over to a local media blasting company before getting it welded up if required...

Likely it turns out that there isn't much to salvage...



The one shown came from a high mileage '94... PO used it during winter months...

I'd source a decent, low mileage one from eBay and give it some serious cavity protection prior installation...

ABS ones will fit all versions BTW...

 

[Oldbikefixr]

Don't bother with the POR15 for your swingarm. It works best for its intended purpose, sealing de-rusted fuel tanks from the inside. It's also a bit finicky about application method. Certainly isn't tough enough to protect your swingarm from daily use for very long. A decent epoxy primer and paint will certainly improve
Once your part is blasted clean, check it out for pinholes, those will indicate you have some degree of rust inside. Safe approaches include coating the inside with a rust sealer, welding patches over the holes. If I'm recalling correctly the early units had several openings that exposed the interior to a the gradual exposure to road salts that became a problem in nations using that to clear ice from roadways. If yours is a pre-1996 ST, look for them. There are several suggestions you can search on ...upper right of the this screen...'St1100 swing arm' or some keywording should pull up discussions on this topic.

If your swingarm looks anything like this Ebay gem, give it a thorough inspection. Likely this owner's frame pivot and muffler support are in similar condition.



When you get it back from the blaster's, post some photos and show us what you found.

 

[Hissnspit]

I have taken the thing off and, as expected, it is rotten from the inside out. I degreased it a bit, attacked it with a copper brush on the end of an angle grinder and enlarged one of the holes so as to better see what was going on inside and to extract the large flakes of rust that were rattling around.

I attach a handful of pictures for the interested to peruse and would value opinion on whether or not this can be welded back up, painted and reinstalled on the bike?

Thanks.

 

[ST1100Y]

The loss of structural integrity on the part shown raises safety concerns ...
I'd roam eBay for a used low mileage part...

 

[Hissnspit]

The loss of structural integrity on the part shown raises safety concerns ...
I'd roam eBay for a used low mileage part...

Yes, I am inclined to agree with you. It does raise the question, however, of whether used parts listed on ebay or elsewhere are in the same sorry state; It is very difficult to tell from a photograph.

I have noticed a few used swingarms on a dutch site - there must be five or six of them - but again, what is the real state of them..?

 

[Andrew Shadow]

I would suggest that it needs to be replaced. Rust does not attack the entire part equally, but it does attack the entire part. When the rust is as bad as what your pictures show, and bad enough to have progressed to the point where it has caused significant perforations, in those locations where there is no perforation the metal will still have been attacked and will be weaker than the metal of a swing arm that is not badly rusted.

In my experience on this site, this is a problem that primarily affects ST1100's ridden in the UK. We don't see this problem being reported from other regions. This seems to be due to a combination of plenty of very humid salt air, and the products that are used on the roads in winter. A swing arm purchased from an ST1100 that was ridden just about anywhere else besides the UK will probably be in good shape.

 

[Hissnspit]

I would suggest that it needs to be replaced. Rust does not attack the entire part equally, but it does attack the entire part. When the rust is as bad as what your pictures show, and bad enough to have progressed to the point where it has caused significant perforations, in those locations where there is no perforation the metal will still have been attacked and will be weaker than the metal of a swing arm that is not badly rusted.

In my experience on this site, this is a problem that primarily affects ST1100's ridden in the UK. We don't see this problem being reported from other regions. This seems to be due to a combination of plenty of very humid salt air, and the products that are used on the roads in winter. A swing arm purchased from an ST1100 that was ridden just about anywhere else besides the UK will probably be in good shape.

That is a very interesting observation. Certainly we do have highly corrosive salt sprayed on our roads in the winter, but we're not alone in that. As far as I am aware, all western european countries treat their roads in the winter, although whether or not they use the same stuff to do it with I don't know.

ST1100Y shared swingarm pictures above that demonstrate the same level of deterioration as mine and I guess that occurred in Austria (I stand to be corrected)?

It would be nice to think, though, that I could source a replacement from just about anywhere other than the UK and it would be servicable!

 

[George]

I replaced the swingarm on STick at about 200,00 miles. Had previously patched a couple hole but did no other clean up. I had received, along with the rest of a carcass, a low mile swingarm which made the choice easy.

I had ridden STick through several Chicago winters. Her rust was no where near the level shown in these photos. Find a good replacement and move on.

 

[Andrew Shadow]

Certainly we do have highly corrosive salt sprayed on our roads in the winter, but we're not alone in that. As far as I am aware, all western european countries treat their roads in the winter, although whether or not they use the same stuff to do it with I don't know.

Maybe most other European countries where the roads are treated have winters that are just that much colder then the UK so that those people are not riding in the winter when these conditions are present? Maybe they use different chemicals? I don't know. It just seems that severe swing-arm corrosion, especially on lower mileage bikes, is most often reported by ST1100's used in the UK.

 

[Upt' North]

That is a very interesting observation. Certainly we do have highly corrosive salt sprayed on our roads in the winter, but we're not alone in that. As far as I am aware, all western european countries treat their roads in the winter, although whether or not they use the same stuff to do it with I don't know.

ST1100Y shared swingarm pictures above that demonstrate the same level of deterioration as mine and I guess that occurred in Austria (I stand to be corrected)?

It would be nice to think, though, that I could source a replacement from just about anywhere other than the UK and it would be servicable!

Mark, howdy partner. I think it's a combination of Blighty being cold enough to salt, but warm enough to get damp in between the cold that makes our brine extra horrible.
I bought a spare from the states about two years ago which arrived in OK condition. I cleaned it up and painted it with hammerite black spray. The crud gets in through that unwelded flap on the offside, plus the other holes.
Whichever way ya jump make sure you inject waxoil everywhere.
Be aware that although the Stateside one's seem cheap, postage and duties will be horrible. I think I had to pay around £90 in handling and duties plus the postage for a $25 swingarm. But for £200.00 it's tidy and awaiting fitment whenever necessary. If not then I'll flog it eventually. But not yet......sorry.
Also, not all US swingarms are that good, so be careful.
Good luck.
Upt'North.

 

[Hissnspit]

Mark, howdy partner. I think it's a combination of Blighty being cold enough to salt, but warm enough to get damp in between the cold that makes our brine extra horrible.
I bought a spare from the states about two years ago which arrived in OK condition. I cleaned it up and painted it with hammerite black spray. The crud gets in through that unwelded flap on the offside, plus the other holes.
Whichever way ya jump make sure you inject waxoil everywhere.
Be aware that although the Stateside one's seem cheap, postage and duties will be horrible. I think I had to pay around £90 in handling and duties plus the postage for a $25 swingarm. But for £200.00 it's tidy and awaiting fitment whenever necessary. If not then I'll flog it eventually. But not yet......sorry.
Also, not all US swingarms are that good, so be careful.
Good luck.
Upt'North.

Thanks for the tips. Finding one is the tricky part. There are a few around, but separating wheat from chaff from just pictures is nigh on impossible. Guess I'll just have to take the plunge and hope not to get stung. All started with a leaky exhaust system...

 

[ReSTored]

We use huge amounts of salt to keep winter roads open. Key difference is that 99% of riders here store their bikes over the winter in November or at first snow or salting vs. riding them virtually all year long.

 

[ST1100Y]

Maybe most other European countries where the roads are treated have winters that are just that much colder then the UK so that those people are not riding in the winter...

Exactly the issue...
(recalling the debate with a UK HVAC engineer about exceeding low ambient benchmarks for a kit to suit it for the European market, and he just barked "Why?! We have -2°C here!!" at me... )
Over here (on the continent) we do have temps way below freezing, we do have snow and ice covered roads, hence the bikes goes in the garage once the weather turns...
Thanx to Humbold the UK sees temps around freezing, so they get away with riding year round, but due the also humid conditions is there pure brine on the road...
Daily rises with clean water would help, but...

 

[Bush]

Well, here's a brand new one, if you want to pay the price. In the UK too, it says.

David Silver Spares

David Silver Spares Honda Part Number Search

www.davidsilverspares.com

 

[Hissnspit]

A(nother) question: Are older, non-abs, ST1100 exhausts compatible with later models - mine is a ST1100Y and there are a few used swingarms about that came off of earlier models from 93, 94 and 95 etc?

 

[jfheath]

The earlier models have a different part number. Pre 1996 seems to be the change according to what I have just looked up on Fowlers site.

The david silver swing arm is on the uk site and at £570 is about £340 cheaper than the price that fowlers are listing.

Its a lot of money, but its not the new price you have to consider, its the extra price over buying second hand. How much is peace of mind worth to you? And welding. You can see the state of the inside. What are you going to be welding to ?

The same model number 52100 MAJ G40 is listed for both the ST1100Y and the ST1100AY which is what the David Silver part is.

I suppose you have to ask the question - how much am I going to have to spend in total? Is it worth it to you ?

---

Exhausts ? Again the pre 96 models have a different part number. ABS / non ABS seem to share the same parts though. I don't know this - I just looked up the fiches on Fowlers.

But always check on Uk sites - eg Fowlers.co.uk - for the part that you require and the model of the bike that the second hand part was fitted to.

 

[Hissnspit]

The earlier models have a different part number. Pre 1996 seems to be the change according to what I have just looked up on Fowlers site.

The david silver swing arm is on the uk site and at £570 is about £340 cheaper than the price that fowlers are listing.

Its a lot of money, but its not the new price you have to consider, its the extra price over buying second hand. How much is peace of mind worth to you? And welding. You can see the state of the inside. What are you going to be welding to ?

The same model number 52100 MAJ G40 is listed for both the ST1100Y and the ST1100AY which is what the David Silver part is.

I suppose you have to ask the question - how much am I going to have to spend in total? Is it worth it to you ?

---

Exhausts ? Again the pre 96 models have a different part number. ABS / non ABS seem to share the same parts though. I don't know this - I just looked up the fiches on Fowlers.

But always check on Uk sites - eg Fowlers.co.uk - for the part that you require and the model of the bike that the second hand part was fitted to.

Thanks for this. Yes, you are quite correct: it's not the money but the safety. As for the exhaust, I will go the Delkevik route. Rough and ready maybe, but very available and a lot cheaper than OEM!