Try the black high temp silicone.
People will appear and try to prove you and your experience as wrong as soon as you claim a product doesn't work that worked for a friend of a friend of theirs. They're outliers. Just the law of the universe at work - people will claim talking to invisible dead people helps them get a car park if you look hard enough. Just as people will claim the orange sh*t works or the Homeopathic remedy of dilute water cured them.
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MC21 Honda NSR250. TYGA 300 conversion.