Check steering head bearings,front/rear wheel alignment.Front wheel bearings.Do a wheel balance.How many miles on the tyre? I had one that went away 5kph either side of 80kph.Fixed it[I think] with new tyre.At 100mph though???
Dinosaur.
"Oh Man I only ride 'em.I don't know what makes 'em work". Donald "Oddball" Sutherland
"Don't let the bastards get you down". Kris Kristofferson
"I am only paranoid because everyone is against me". Larry [Frank Burns] Linville