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Author Topic: 1982 CB750F... The resto-not  (Read 16116 times)

Offline advCo

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Re: 1982 CB750F... The resto-not
« Reply #440 on: Mar 14, 2019, 12:12:21 »
Yeah, I think that's it.  Need to dial down the drill.  Even with the fine grit stones I'm guessing the honing tool removes material from the inside of the sleeve, and so overdoing it is a no-no?

Yep. You basically want to go the least amount possible to get a good 45 degree cross hatch.

Offline cxman

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Re: 1982 CB750F... The resto-not
« Reply #441 on: Mar 14, 2019, 19:32:30 »
get a ball hone or some call them flex hones

with the 3 jaw hones you will bell mouth the cylinder before you get nice crosshatch

a well lubed ball hone you are done in a minute less than 1/2 thou removed

and the cylinder is degalzed and cross hatched
1978 CX650 Super Deluxe
1979 XS1100 Special
1974 xl350
1983 cx650 Custom
1973 cb750
1980 cb750
1981 cb650
1982 cb900 c
1974 kawasaki 350 bighorn
1983 GL1100 aspy full dress
1983 GL1100 Nekid
and a bunch of others

Offline Jimbonaut

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Re: 1982 CB750F... The resto-not
« Reply #442 on: Mar 17, 2019, 11:57:52 »
Worked on the brake calipers yesterday, man they're crusty.  Thankfully I now have a small air compressor in the garage so getting the pistons out wasn't too much trouble, but one did need some encouragement from some pliers to get it past the roached seals.  The piston is slightly scratched and I'm pretty sure I can clean it up with some fine grit sandpaper and some Autosol metal polish.  Is that cool?  I'll be careful no to remove any material from the piston - just the scratch.

The seal grooves inside each caliper are in pretty rough shape too, and the seals were all completely destroyed (whoever rode this beast last must have had zero heel left on their boots - I think that must've been the only way they got this thing to slow down).  I used mechanic's picks to remove all the crud in there, and will let them sit in some clean brake fluid for a while too.  Is there anything else I can/should do to get these thing clean before rebuilding them?

The rear brake master cylinder however was in the worst shape.  The thing just looks awful - all the seals are toast and it's covered in crystallized brake fluid.  Once I got the boot off to dig out the circlip, it looked full of rust and the circlip ain't budging for love or money - in fact it shattered my circlip pliers trying to remove it.  Any ideas on how I can get that thing out?  Tried soaking it in PB Blaster to - so far - no avail.
"I'm telling you Donnie, nuthin' but nuthin' but right"

Offline cxman

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Re: 1982 CB750F... The resto-not
« Reply #443 on: Mar 17, 2019, 20:01:07 »
boil it in water that covers the master cylinder  with 2oz of lemon juice that will loosen most of it up

boil for 10- 15 minutes then try removing the ring while its hot
1978 CX650 Super Deluxe
1979 XS1100 Special
1974 xl350
1983 cx650 Custom
1973 cb750
1980 cb750
1981 cb650
1982 cb900 c
1974 kawasaki 350 bighorn
1983 GL1100 aspy full dress
1983 GL1100 Nekid
and a bunch of others

Offline stroker crazy

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Re: 1982 CB750F... The resto-not
« Reply #444 on: Mar 17, 2019, 21:30:03 »
A slow but sure method to remove rust without damaging good metal is to soak it in a mix of one part molasses to eight parts water.
Animal feed molasses is marginally better than that meant for human consumption.
Remove part from the mix every now and then to brush off dissolved rust.

An oldie but a goldie!
(specially on sheet metal when you can't afford make it any thinner)

Crazy
“Ride like the Wind” W.H.

Offline cxman

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Re: 1982 CB750F... The resto-not
« Reply #445 on: Mar 18, 2019, 07:13:55 »
only the rod is steel the master body is aluminum ish
1978 CX650 Super Deluxe
1979 XS1100 Special
1974 xl350
1983 cx650 Custom
1973 cb750
1980 cb750
1981 cb650
1982 cb900 c
1974 kawasaki 350 bighorn
1983 GL1100 aspy full dress
1983 GL1100 Nekid
and a bunch of others

Offline stroker crazy

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Re: 1982 CB750F... The resto-not
« Reply #446 on: Mar 18, 2019, 07:34:12 »
the molasses mix won't hurt the alloy ...
“Ride like the Wind” W.H.

Offline CrabsAndCylinders

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Lighter, Quicker, Faster.
ZX-14, 900F x 2, 1100F, R100, CBR600, SR500, GT500, RZ350, KZ1000 x 2, Moto Guzzi Lemans lll, CBX550, RD 350, 750 SOHC police special, RG250, TL1000R, GT750, KTM Super Duke 1290 R, Harris/Z-1, Norton 750 Commando, Green 77 KZ650

Offline advCo

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Re: 1982 CB750F... The resto-not
« Reply #448 on: Mar 18, 2019, 12:18:12 »
Vinegar?

You'll probably have to break that circlip to get it out. They are a PITA to reach with snap ring pliers and even if you can get to them they never want to come out. The last MC I rebuilt I broke the circlip into pieces and pulled out the chunks. Replacing it is easy as you can use the snap ring pliers to get it to fit in the bore, and then use a socket thats close to the same diameter as the bore to push it down evenly until it seats.

Offline Jimbonaut

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Re: 1982 CB750F... The resto-not
« Reply #449 on: Mar 18, 2019, 12:32:09 »
Thanks guys - I ended up leaving the thing soaking in PB Blaster overnight and then attacking the circlip with a couple of mechanics picks.  Wrestled that thing out, then had to manhandle the piston and its washer.  Man what a mess.  Still, got it all out and hopefully the master cylinder itself will be salvageable.  The bores cleaned up ok -




Good to learn about those rust-shifting techniques.  I've used Metal Rescue before on a rusty gas tank - that stuff is the business.  Has one job to do, and does it brilliantly.
"I'm telling you Donnie, nuthin' but nuthin' but right"