Blue paint bubbling and peeling off cylinder heads

[Maitre]

Posted in the Rockster section which is dead.
Any remedy to the blue coating bubbling, bursting and peeling off the heads? Trying to prevent them from corroding.
I have two photos but no idea how to insert them here
Thank you

[towerworker]

I had a Ferro blue '04 with the blacked out engine. In 18 yrs and well over 100K I never had paint just "bubbling" or lifting off the calve covers which I think are magnesium. That being said I did repaint them several times due to damage I caused. For a time I was recovering from an illness that paralyzed me and my bike lived a very hard life for a few years from falling over due to leg weakness on my part. During that time I would pull the valve covers, sand them and then spray with an automotive primer. (rattle can) Then spray with black gloss paint. It wasn't a perfect match but unless you could park it next to an identical bike I don't think you'd notice anything different. I think if your paint is lifting off the covers as you say you probably need to strip them and repaint. I say strip and not simply sand because if it's bubbling in one spot it will most likely do the same in others. Apparently the heads (or valve covers) weren't properly painted initially. I'd find some sort of paint stripper appropriate for the metal and probably start over.

[Maitre]

Strip and high heat black paint. Magnesium corrodes

[sweatmark]

Maitre

Did you find a solution?

The paint in early 2000-production BMWs is a problem, especially for magnesium and aluminum alloys used for parts exposed to environment.

My current Rockster has big paint (oxidation, actually) bubbles on the valve cover, and erosion/flaking of paint on forks castings. The defects don't bother me, since they represent some of the particular "charm" of this motorcycle family. But I have been interested in doing something different, specifically for the valve covers.

Let us know what you choose!for paint and surface preparation.

[kirby]

111

[kirby]

Post by kirby » Fri Dec 09, 2022 7:37 pm
My Rock is an '04 and has over 300K miles. About a year ago I started seeing the mag in the valve coves starting showing signs of corrosion.

I removed them on the next heavy maintenance period and soaked them in aircraft paint stripper for a couple of days and then prepped them with some real good solvent for a day and dried them thoroughly.

Ordered paint from a company in England and with a very good primer(3 coats) then painted them the original color. Perfect match to the original.

Since the original paint lasted for 16 years with out any extra care I will this time take pains to keep them waxed and clean.

Cheers.

Good to see some activity here...

:-)

[Maitre]

Maitre

Did you find a solution?

The paint in early 2000-production BMWs is a problem, especially for magnesium and aluminum alloys used for parts exposed to environment.

My current Rockster has big paint (oxidation, actually) bubbles on the valve cover, and erosion/flaking of paint on forks castings. The defects don't bother me, since they represent some of the particular "charm" of this motorcycle family. But I have been interested in doing something different, specifically for the valve covers.

Let us know what you choose!for paint and surface preparation.

sorry for the late reply.
I scraped the corroded areas and then applied two coats (less than a can) of Rust Oleum High Heat (2000 deg F) black paint which I bought from Lowe's.So far so good. I don't sweat it much, if I see that it doesn't last in the future I'll replace the covers.

[Tigcraft]

Very late to post although I’m always intrigued by paint problems that are uncommon as I used to paint for a living