Discoloration/stains on fork tubes

[2ndclasscitizen]

I'm looking around for a new bike and came across an ad for a 2007 Guzzi 1200 Sport. Price is good and it seems in ok condition for its age/price, but in the photos it has this weird stains/marks/something on the fork stanchions:




I've not seen anything like that before. It doesn't immediately seem to be from leaking fork seals as there doesn't appear to wet fork oil on there. Kind of looks like discoloration from heat if anything. Does anyone have idea what it could be? The bike's a couple of hours away so don't really feel like a long round trip to find out the suspension is absolutely cooked.

[Drawweight]

It couldn’t just be ACF-50 or similar that they’ve put on the fork legs to prevent corrosion and it’s dried off?

[Shinysideup]

I've seen this happen on Marzocchi mtb forks of a similar age. 2007-08

https://www.pinkbike.com/buysell/2601301/

I think it's caused by oxidisation of whatever coating they used at that time.
Possibly nickel based outer coating.

None of the forks i've seen affected by this had a reduction in performance and i never attempted to polish it out.

Just thought i'd post incase they happen to be Marzocchis on the Guzzi

Edited by Shinysideup on Tuesday 28th July 06:14

Edited by Shinysideup on Tuesday 28th July 06:17

[LFB531]

Good choice!

My forks are similar, hopefully the pic shows. I thought fork seals but not convinced, about to go in for an MoT so will get an opinion then. The nose can dive but I put it down to those monster brakes and suspect adjustable damping on the soft side.



I've had my '07 Sport since March and it's still making me smile!

[jjones]

Same thing on older gsxrs, the gold coating rubs off where it goes past the seal so you end up with a gold and silver fork tube.

[2ndclasscitizen]

jjones said:

Same thing on older gsxrs, the gold coating rubs off where it goes past the seal so you end up with a gold and silver fork tube.

Shinysideup said:

I've seen this happen on Marzocchi mtb forks of a similar age. 2007-08

https://www.pinkbike.com/buysell/2601301/

I think it's caused by oxidisation of whatever coating they used at that time.
Possibly nickel based outer coating.

None of the forks i've seen affected by this had a reduction in performance and i never attempted to polish it out.

Just thought i'd post incase they happen to be Marzocchis on the Guzzi

Not sure if they're Marzocchis but a bit of googling has brought up that they have the TiN coating, so likely to be that I'd say, cheers lads!

LFB531 said:

Good choice!

My forks are similar, hopefully the pic shows. I thought fork seals but not convinced, about to go in for an MoT so will get an opinion then. The nose can dive but I put it down to those monster brakes and suspect adjustable damping on the soft side.



I've had my '07 Sport since March and it's still making me smile!

Thanks mate, makes me feel a bit more confident about it. How do they go on a long trip? I've read a few reviews nitpicking the riding position and windblast.

Edited by 2ndclasscitizen on Wednesday 29th July 00:16

[Benni]

That golden fork posted by jj seems rather borked to me,

not only is the gold coating rubbed off but also the silver coating seems scoffed in the seal area in one spot.

Or is that just a trick of light & reflections ?

[Steve Bass]

It's simply the anodising wearing away.

Brooks Suspension can re-treat them to better than new.

[LFB531]

2ndclasscitizen said:

Thanks mate, makes me feel a bit more confident about it. How do they go on a long trip? I've read a few reviews nitpicking the riding position and windblast.

Mine came with the standard naked style spoiler, changed it since for a double bubble which improves things but it's not restful above legal speeds.



Having said that, the riding position suits me at 6' but with short legs/long arms, seat is good, it vibrates a bit through the pegs and bars but not unpleasant and it sounds great. Loads of torque and will hustle along if asked.

The longest single stint I've done was maybe 2 hours and no problem then.

I bought it because I liked how it looked (typical PH!) and took a chance during lock down, no regrets at all!