I’m replacing the discs on my 1996 900 monster tomorrow, I sprayed everything with WD40 tonight, probably won’t help but anything is worth a try, tomorrow I will start by tapping the fasteners lightly from side to side with a drift, tapping them end on with an Allen socket, heating them with a mini blowtorch, putting a tommy bar on the allen socket and giving it a sharp crack with a heavy spanner to try to shock them, (I’ve got an electric impact driver but it’s quite a powerful one so that’s my last resort), are there any other techniques that I should try first?, thanks Mark . PS I have tried to get one moving with a long Allen key but it’s tight as hell!.
You can get proper penetrating fluid like de-grip that's loads better than wd40. Maybe someone got carried away with the wrong thread lock.....
Removed the four bolts on my rear disc a couple of months ago to replace the with Ti ones. They were the factory fitted ones and were proper bastards to get out. I used a manual impact driver and lump hammer but still took several blows to loosen them. Heat would definitely help.
Do not, under any circumstances use an impact driver. The OE bolts are made of cheese as I found out to my cost. Andy
I thoroughly recommend this as a penetrating fluid. In restoring my 748 I started with WD40, then used XCP or whatever it's called, then bought this and tried it - 10X better; it works every time, even freed off the dreaded swingarm pivot bolt on the 748, a known baddie, even thought it had never been removed for 20 years and the bike had been stored outside for 6 years it came out without any problems . I picked it up in a motor factors, not a bike shop.
They weren’t too bad to get out, socket Allen key, tommy bar and a sharp crack with a spanner on the tommy bar moved them, god knows what the PO has used as a locking agent, it looked like araldite!, anyway all done been out this morning and it’s so nice not to feel the “tug,tug,tug” of a warped disc, I’ve used Chinese discs, £128 for the pair, I was talking to my MOT guy yesterday , he’s a biker/racer and he said he’s got a few customers that have used them and had no issues in thousands of miles so I’ll see how they go. It wasn’t a good application for penetrating oil as there is really no way for the oil to reach the threads, it’s only really useful on exposed threads where if you’re lucky it works it’s way down the thread into the nut, regarding penetrating oils this video is interesting.
If the Allen bolts start to distort, I’ve sometimes had more luck with a similar size torx bit, heat the head of the Allen bolt up, dip the end of the torx bit in some carborundum paste ( gets better grip) and tap the torx bit into place, let everything cool and give it a try. Good luck
One thing I did notice when reassembling was that the speedo drive casing was lightly fouling against the disc fasteners, at first I thought I’d missed a spacer but had a look on my 900ss and there’s virtually no clearance, so I removed about a mil from the plastic housing so at least the bolts don’t contact it now. Photo is before I removed the material.
