removing front caliper 81 maxim 650

I finally got my front wheel of my 81 650 yesterday.The 10 mm bolt on the bottom of the speedometer senser was not allowing the spindle to be removed.After doing that it came out.I hope there is a mark on the speedo drive unit to show where to realign it.But now the caliper has never released from the rotor.The mounting bolts to the fork have been removed.There is a stud with 12,mm bolt on it that also penetrates a fork mounting.I took the nut off.Using a hammer and block of wood still does not make it release. I was wondering if i opened the bleeder screw if that would help it release. In the manual is says remove the inner caliper mounting screw.maybe thats the problem.usually removing the mounting bolts makes the caliper slide off easily.Input appreciated.

 

Are you saying you got the wheel off but the caliper and rotor are still on the bike? That must've been challenging! If the brake is locked on due to pressure then yes releasing the bleeder will release the brake. If it's gummed up, rusted, stuck then you'll need to mechanically spread the pads apart. Once that is down, the caliper should come off by removing the bolt that holds it to the fork lower.

 

If it's like my 82, which I'm positive it is as the gf's 81 is the same, the nut on top gets removed then you have to unscrew the bolt from the bottom as it is threaded into the fork leg.

 

thanks for the pictures.its 95 degrees outside,probably 120 in my garage.I will check for those places.if its in the fork leg it looks like the nut over the stud on top of the caliper goes into the fork leg.there must be something below I havent removed.I will look again. And no, the rotor came with the wheel.the caliper is still there.the stud that comes from the top of it and goes through the fork leg had the 13mm nut I removed.maybe 12mm.Anyhow, I thought I could tap on the stud, drop the caliper completel free of the forks.I cant rebuild or check the pistons etc with it still hooked to the forks.plus i thought with it free of the rotor if i squeezed the brake lever i would see the pads area contract closed and open back and forth.They dont move,thats why I think the caliper piston is frozen.I can put compressed air on the bleeder screw and get the piston out, but i have to get the caliper completely off the bike.

 

assembly drawing
https://www.partzilla.com/catalog/yamaha/motorcycle/1981/xj650-xj650h/front-brake-caliper

 

That’s not a stud, it’s a bolt that threads into the fork leg and has a nut on top to lock it. Once the nut is off, there is (should be) a plastic cap on the bottom of the caliper. Pop that off and back the bolt out. Tapping the top after removing the nut wont do you any good.

 

ooooooh.wow.thanks brother.

 

I have a new problem.the piston did not move at all on the 81.The front brakes were working on the 82.I switched calipers.I installed new disc brake pads.the extra thickness made it rough to get over the rotor.It never did seem to fit right.Putting the long through bolt in the caliper was more difficult than I thought it should be.But I got everything on.The nut on top of the through bolt, the little protrusion from the pads into their slots,all seemed good.I used my mightyvac for the first time.I have bled and bled,refilled the reservoir as it went down.Finally the reservoir stopped emptying so I figured i had it.The rubber cover from the mightyvac completely covers the bleeder screw so there is a slight delay before the bleeder screw can be tightened.Anyhow, the brakes do not work at all.The bike kinda slows down,very neglible. I took the caliper back off.I squeezed the brake lever.of course the pads are just dangling.The inside piston moves almost none at all.I figured if I pumped the brake handle several times the piston would keep emerging outward.With the thick new pads the piston was most likely fully compressed.The inside of the piston barrel is rusty.The inside of the one I took off is pretty clean looking steel.I am thinking the piston is not moving outwards to push the pads against the rotor.When it was on the parts bike i could push it and squeeze the brake handle and it definitely would stop,even though it wasnt running.I expected it to do the same. I am thinking buy a rebuild kit, manage to get the piston out, rebuild it and it would work.I am confused.When I was backing the nonrunning parts bike off the trailer the front brake worked good enough to gradually let it down the ramp.It did sit for a month, but still connected on all points for a month.I am also thinking the rusty one is not the best of the 2. Opinions appreciated.