I needed a pair of top caps from adjustable Showa forks to fit a 50mm top yoke and purchased a set of obviously corroded forks from Ebay VERY cheaply just to strip from them the parts I need. I knew from the pictures on the auction that they were bad, but now they've turned up I'm a little shocked at just how bad the sliders/outers are. It's obvious the Anodising has been compromised round where the yokes fit and on the left leg where a brake hose has rubbed through. But once the anodising was compromised these legs look like they were stored in sea water. Where the brake hose rubbed it looks like the corrosion has almost gone right through it's so deep. The Stanchions are actually not too bad, pitted, and not to be reused, but nowhere near as bad as the sliders.
Surprisingly all the adjusters are free to turn and operate smoothly, and the damper bolts in the bottom castings have loosened off really easily. The bottom castings are stamped '3P'. I wonder if that means anything. They were sold as Carb 900SS and are obviously very early ones because of the separate bottom sections on the sliders
"...The bottom castings are stamped '3P'. I wonder if that means anything.... Because that's all I'd give you for them - 3p Seriously though, people don't realise what the anodising is there for and how readily the aluminium alloy corrodes when exposed to the lovely combination of water, salt, etc...
I had a 996 with similar and once it's taken hold it's like wet or dry rot in wood, and it's nearly always past saving once you find it. I always soak my yoke clamps with GT85 or similar on a winter bike as loves to start pickling here, particularly lower yoke/lowest face where it meets the "tubes".
Thanks guys I've seen plenty of Galvanic Corrosion on submerged parts of outboard engines and stern gear which is as bad as these forks, but have never seen Forks this bad.
Good lord!! that is shocking... my V-Raptor has been out in all weathers for 4 years or so and apart from a smear of ACF50 in the clamps, more for ease of fitting than anything else the forks are, if not perfect, only showing a little weariness. All all forks galvanised? Cus these are still an aluminium colour.
You can't galvanise aluminium it's for steel or iron. The forks will be anodised if anything... Or laquered/painted.
Oops my bad... I meant anodised as mentioned earlier in the thread. But I was wondering why my forks didn't show particularly bad corrosion, was it because they weren't anodised?
LOL. There's def something going on with them. Not sure what failing anodising looks like, I thought it started by looking faded....
it's a massively fascinating subject, rather than me add observations, best wait for a metallurgist to quote from text books, but I will add, that you can take all the preventions to ensure the outer faces aren't compromised but still experience corrosion erupting from beneath the surface.
On my recent recommissioning of the Darmah I thought the same and put a short length of that spiral plastic sheathing they use for wiring looms at the point the lines touch the forks.
I had a 900SL for servicing and spotted that the aftermarket unsheated brake lines had nearly worn through the RH fork slider but there was no obvious corrosion as the movement of the brake line with the suspension had kept it clean. I did though come across a 749 a couple of years ago where the corrosion to the sliders was even worse than Nashers. One of them was so bad that the fork seal was almost falling out
Just had a look at the fork sliders on the 916 i bought earlier this year as a bit of a project, and there is some corrosion evident on the upper sliders as per @Chris above post, the left leg looks worse than the right, simple question - is this a MOT fail or is the MOT just focussed on the actual forks ie. pitting/leaky seals etc?... the bike is a work in progress and fresh forks were on my list for replacement at some point.
It shouldn't be a fail if the forks aren't leaking, unless it is so bad that the tester considers them to be "seriously weakened".
Ok thanks, they're more of an eyesore really , I guess there's nothing to do to stop the corrosion worsening other than have the sliders machined down or fit replacement forks?.
