20-01-13, 07:10 PM
I found them extremely reluctant to undo when I changed my disc last year. The threadlock Yamaha use seems to get stronger with age. Front discs I never had much problem with, but the mileage I do means those get replaced every 3 or 4 years... the bolts on the back disc hadn't been touched in 13 and wanted to stay put.
I tried a gentler heat than a blowtorch at first, propped the whole thing up a foot above a small ring on the gas hob and after 20 minutes or so it was just getting too hot to touch. All but two of the bolts came out fairly easily then with an extension on the allen key.
Those last two needed less subtle treatment... I ended up welding a length of scrap steel to the remains of the heads. Massive leverage and the more extreme heat did the trick.
I tried a gentler heat than a blowtorch at first, propped the whole thing up a foot above a small ring on the gas hob and after 20 minutes or so it was just getting too hot to touch. All but two of the bolts came out fairly easily then with an extension on the allen key.
Those last two needed less subtle treatment... I ended up welding a length of scrap steel to the remains of the heads. Massive leverage and the more extreme heat did the trick.