FRANKENHONDA II the 1982 DOHC CB 750F2 Build

hold the caliper up in the air and roll it around to work the air to the bleeder, then take a few shots out of it. pump the pads out then push them back - don't spray fluid out of the reservoir everywhere. unbolt the master and roll it around to let the air back into the supply hose, maybe use a rod to move the piston a little to help the air come out.

does that master/pedal setup have a pedal stop that keeps it from allowing the piston to come all the way back? maybe it needs the rod shortened for some freeplay? the japanese systems tend not to be constrained like the brembos i deal with every day, so i could be talking through me hat.
 

cb250nproject

If you can make it better do so
brad black said:
hold the caliper up in the air and roll it around to work the air to the bleeder, then take a few shots out of it. pump the pads out then push them back - don't spray fluid out of the reservoir everywhere. unbolt the master and roll it around to let the air back into the supply hose, maybe use a rod to move the piston a little to help the air come out.

does that master/pedal setup have a pedal stop that keeps it from allowing the piston to come all the way back? maybe it needs the rod shortened for some freeplay? the japanese systems tend not to be constrained like the brembos i deal with every day, so i could be talking through me hat.
Brad the rear brake is off an R6 i can see a thread and nut at the back of the piston, does that mean i can adjust the piston ?
 

pidjones

Well-Known Member
Often you need to "prime" the MC by pumping a little fluid out of it before tightening the banjo/fitting out of it.
 

teazer

Well-Known Member
DTT BOTM WINNER
No comments from me about that tiny butt plug or popping its cherry (red) ...

Try RAISING the caliper so it is the highest point to get air bubbles to rise.
 
cb250nproject said:
Brad the rear brake is off an R6 i can see a thread and nut at the back of the piston, does that mean i can adjust the piston ?
dunno. is there anything stopping the pedal going to where the piston pushes it back to? on the euro brembo stuff i deal with there is a pedal stop, so the pushrod length against the piston is important to maintain some freeplay and ensure the compensating port is clear. but if there is no pedal stop as such, and/or the pushrod is part of the piston and the piston sets the pedal position, then it's not an issue.
 

cb250nproject

If you can make it better do so
So after watching a YouTube, and previously breaking a chain breaking tool on another chain, I decided to angle grind the head off the rivet before pushing the pin through. Then easy peasy the pin came out.

Unfortunately I think I over did it on the right pin. Hopefully they sell additional links for idiots like me.

The rear brake continues to beat me, I cracked the banjo at the piston and bled it there and it got worse :/ I even removed the pedal and master cylinder to raise it up in an attempt to have any air float up to the master cylinder but no joy.

As I was taking it down from it’s centre stand I was playing on the front breaks easing it down and it felt as if there was play in the head stem ( add to list of things to check upon my return)

I’ve ordered a new starter solenoid which should arrive and I’m thinking of running with a cycle x tri -y system cone muffler it’s 12” long which should sit perfectly.

It’s fly out day tomorrow so that’s all the work I’ll be getting done for the next six week.

Hopefully next break I fix the final round of gremlins before sending it away to get tuned properly and have the shims redone

It would be super rad to be rolling in September






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Jimbonaut

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DTT SUPPORTER
Just a thought on that master cylinder. Did you rebuild it? I rebuilt the MC on my KLR - inside the thing is a piston with a concave washer on it. I couldn't get the rear brake to actuate at all, it wouldn't pump any fluid through the lines after hours of bleeding. Couldn't figure out what the hell was the problem until I took the MC apart and realized I had that washer on the wrong way round. Flipped it, rebuilt it and it started working right away.
 

cb250nproject

If you can make it better do so
Never rebuilt the master cylinder, maybe I should have. The banjo on the MC pushes fluid out so I’m guessing it works... but that will be a problem for 6 weeks in the future me


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cb250nproject

If you can make it better do so
The MC is off an R6 it came with the rear sets, it’s not the original. That definitely did need a rebuild.


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teazer

Well-Known Member
DTT BOTM WINNER
I see that two of us suggested leaving the M/C in place and raising the CALIPER so that air rises to the bleed nipple in the caliper. Don't raise the M/C, that allows air back into the m/c and it travels back down the hose again.
 

cb250nproject

If you can make it better do so
So my cycle x muffler came in the mail, it was a stainless finish, so I needed to do a little polishing so it would match the headers.

Next I tried to bleed the rear brakes using my new brake bleeding tool, but I’ve run into an issue.

So when I try to use it on the nipple I can’t pull fluid through. I removed the brake line to the caliper and I’m able to draw the fluid through the line no issue, but when I connect the line to the caliper and try to draw the fluid through nothing comes out.

So close yet so far away


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Jimbonaut

Well-Known Member
DTT SUPPORTER
Bleeding the rear brake shouldn't take too long as the brake line is pretty short, as long as your caliper and MC are all in good working order. If that air tool is causing you grief you could always go old school - make sure you've got fluid in the MC reservoir, depress the brake pedal 4 or 5 times, keep it depressed while cracking and then closing the bleed nipple on the caliper (attach a hose to the nipple to cleanly drain the fluid into a bottle or something), and repeat.

The fluid level in the MC reservoir will drop - make sure you keep it filled during the process or you'll introduce air back into the system and you'll have to start all over again. It shouldn't take that long to do as long as everything is in working order. Did you rebuild the MC?
 

pidjones

Well-Known Member
Was bleeding the front calipers on my '79 GL1000 (the old fashion way) and got nothing out the right side bleed screw. Pulled it out, and it was plugged with rust! Drilled the plug out and then it bled normally.
 

Maritime

Well-Known Member
pidjones said:
Was bleeding the front calipers on my '79 GL1000 (the old fashion way) and got nothing out the right side bleed screw. Pulled it out, and it was plugged with rust! Drilled the plug out and then it bled normally.
Been there. I like to start with a dry system, get a big ol syringe, I used a meat marinade one, put some hose on it, fill it up and connect it to the nipple. Open the nipple and push the fluid through until the MC is full. No air ever and done in a minute. Put the cap on the MC lose or else you get a rain shower of brake fluid, ask me how I learned that ;D
 

cb250nproject

If you can make it better do so
So I removed the entire caliper and all the bolts including this one at the back of the caliper.

I hit the caliper with compressed air, then put it all back together. I tried using the brake bleed tool still wouldn’t draw the fluid through, so I just tried the old fashion way and what do you know... boom success, I can’t explain it but I’ll take it.

Next I started looking at my spaghetti wiring and looked at where I’m going to mount the m-lock. There are two holes on the back which are really small, so I decided to use some resin and mount a M6 bolt in to make it easier to mount to the underside of the electrical tray.

Resin is currently setting then I’ll try to mount it.


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teazer

Well-Known Member
DTT BOTM WINNER
Bunnings or Jaycar having a sale on red wires this week mate?

What many of us used to do was to go down the local wreckers/breakers and pick up a complete car wiring harness to strip and harvest different wire colors from. Bike harnesses tend to be a bit short for what you are doing.

Fortunately there are companies selling colored wires in a range of solid colors and stripes. Someone downunder must be supplying the burgeoning classic car industry.

I did a quick google search and found a couple including https://jaydeeautocables.com.au/collections/single-core

https://www.autocablesonline.com.au/

They look a little thick for some of the circuits, but it's some place to start from.
 

wozza

Member
What about the motogadget kit? https://www.shop.modernmotorcyclecompany.com.au/collections/motogadget/products/motogadget-m-unit-cable-kit
Im sure there are cheaper options out there but at least this kit was designed with the m-unit in mind.....
 

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