ST1100 weird headlight goop

[Jerbear]

Hi all, as I am nearing the end of the refurbishment of my ST, I found this old crumbling foam glued all the way around the headlight. Does anybody know what might have been the reason for the PO to do this?
I did not see any foam wrap on part diagrams for the headlight. #1. I'm thinking stopping rain water from seeping thru,but why it's a motorcycle after all, not a boat. #2. Possibly reducing rattling of the Tupperware against the headlight lens? What do you guys think? Also I am reaching limits of my patience trying to fix all the broken off, cracked and split plastic tabs on the plastics. I think about half of the screw posts and tabs is cracked or missing chunks. Someone who owned her before me had no limit when it came to tightening bolts and screws. Negligence like that pisses me off. Rant over. Right now waiting on new Fiamm horns and analog voltmeter, and that will bring me back here with electrical questions soon.

 

[Smudgemo]

Not on either of mine (96 & 97.) I did a thread on how I fixed the broken posts that might be useful. https://www.st-owners.com/forums/threads/an-abs-plastic-repair-suggestion.175722/
Essentially created some donuts out of ABS that I glued in place, but you'd need something left of the old one. I added anti-seize and bought a few new brass nuts so it s/b good to for a good long time.

 

[DeanR]

Each ST1100 headlight I've seen has that foam attached.

 

[Larry Fine]

Each ST1100 headlight I've seen has that foam attached.

Lights that have foam usually have it to block light leakage to the rear.

 

[Smudgemo]

I"m wrong. I just went and looked at the 97 and it's there. Can't believe I didn't notice it..

 

[Upt' North]

The headlights are all like that, probably an anti shock/noise thing. The foam is usually visible around the headlight opening when the headlight is fitted back into its surround.
Upt'North.

 

[Bikeric]

Yep, +1 as both of mine has the foam attached.

 

[Al st1100]

also to dampen vibration

 

[STFlips]

It's also around the front turn signal lights in the mirrors and I was wondering about that too. Vibration may be part of it but I came to the conclusion it's to help keep dust and dirt out of the housings.

 

[Jerbear]

Thanks for the replies guys! Now off to find something that will replace this foaming mess

 

[bdalameda]

The foam is there to insulate the headlight housing. The lights heat up the housing and when you shut off the bike the housing would cool rapidly and condense moisture without the insulation in place. This could cause fogging of the headlight as well as surface condensation on the outside of the housing.

Dan

 

[jfheath]

Thanks for the replies guys! Now off to find something that will replace this foaming mess

Did you find anything that works please ? I've been looking at sticky back neoprene sealing strips for the same purpose. I reckon maybe 6mm thickness would do - but its guesswork. And goodness knows whether the heat from the headlamp would affect the glue.

 

[Jerbear]

Did you find anything that works please ? I've been looking at sticky back neoprene sealing strips for the same purpose. I reckon maybe 6mm thickness would do - but its guesswork. And goodness knows whether the heat from the headlamp would affect the glue.

From what I can remember, I bought some adhesive backed, high-temp, closed cell silicone foam. Probably an overkill, but I like to follow the: "thing worth engineering is worth over engineering" approach. Hope this helps.