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CB750F2 .... silk purse from a sows ear.
SumpMagnet:
Thankjs guys :) I'm really enjoying the process
SumpMagnet:
Baby steps....and supply issues....and all the other nastiness around right now, but some shed time has been found as 'self isolation' of the best kind!
Split down the front wheel to get the discs off ready to clean up and paint, and so I can get the wheel looking nice. It's in pretty good order with just a minor mark on the outer edge and a few light scrathes that will polish out easy enough. The 'spokes' on the Comstars are virtually rust free and will Solvol nicely. No polishing here....just nice and clean.
Getting the spindle out would have been easier if I had loosened the damn nut while the forks were still together and on the bike...... :o
Nut came undone without too much brute force, but the spindle was in need of some WD40 where it has solidified gunk holding it in the spacer. Tea break while it soaked...and it came loose.
Speedo drive had some solidified traces of yellow grease....but worked fine. No sign of worn or damaged gears, so a good greasing and back together.
Discs came off easy...was surprised to see them bolted through the hub, rather than threaded into each side. Pleasantly surprised....as it meant they came off easy. When I have had to remove doiscs on more modern machinery, it has been allen bolts into alloy with threadlock. Not always the best combo....and if you round a head out....it's not fun. For some reason...ther ewas sand in the spaces in the hub behind the discs.... no idea what's gone on there!
Going to wait for the current crisis to wind down bedfore I send the forks off to be rechromed.... but with the yokes ready, the wheel done bar the bearings ( A job I am putting off till later..... cowardice I know.... ) and all the bits to reassemble the forks already bought.... I can almost smell a rolling chassis.
Oh.,...but there was one fly in the ointment...
The rear caliper is FUBAR in all probability.
I simply cannot budge the piston. Not in/out or round. I can see corrosion on the exposed part of the piston. Far worse than the fronts...so that was going to go in the bin anyway. Heat...nothing. Clamped the mole grips on the piston to try and wiggle it round to work it out...won;t move. When I was looking for a master cyliner, E-Bay threw up loads of calipers...but no MC's. Now I want an rear caliper....not one on E-Bay. Oh well...I guess people are not listing stuff right now so they don;t have to go out and post it.... understandable.
But hey.....still got plenty of things to keep me busy. At some point I got to clean the hideous mess off the back wheel.....
Bryanj:
Put the caliper back together if you have split it, fit and tighten bleed nipple, get a grease gun, preferably eith flexi pipe, and remove the nipple end from the pipe. This will now screw into the pipe fitting on the caliper but only 1 1/2 to 2 turns as its a different pitch. Now pump the grease gun and watch the pistons move, one will move first and you will need to put som thick steel where the disc would go(flat tyre lever) to stop it popping out then the second one will move. When both touch the steel remove the greas gun and steel, split the caliper and you should get the pistons out now.
Then the grotty bit!! You have to get all the grease out of the caliper body.
EDIT
Those instructions are for F1, the F2 has only one piston so just screw grease gun into pipe hole and pump.
You can post it to me if you wish, i never yet failed to get a piston out!!!
SumpMagnet:
Rear is only a single piston caliper...so the casting is a one piece deal. Seems to me like a downgrade step from F1 to F2 ... presumably it was cheaper and easier to make?
If I can't get the thing out in the next few days I will happily take up your kind offer. I want to save what I can. The jaw marks in the piston are mine....but as far as I am concerned, piston and seals will be replaced. Reusing and refurbing is all well and good....but I actually want the brakes to work as well as 40 year old brakes should :)
Bryanj:
Single sided piston pistons move farther so sieze less(in theory) but they need sliders which sieze as well!!!!
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