Rear M-Cyl repair kit - 750F1

grewth

CB750 Enthusiast
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Can anyone identify a Tour Max repair kit which will work with the CB750F1 rear master cylinder please ?
Apparently there are no OE kits to be found anywhere, although the OE kit for the early Gold Wing GL1000 can possibly be used with a little jiggery pokery, but allegedly these are hard to come by also.
With all the pattern repair kits on the market, surely there must be something that will work
 
Honda Classics on Ebay https://www.ebay.co.uk/itm/255027698535 stainles pistons with seals you'll need 2 kits one for each side, very good quality and fitted perfectly, they are very helpful and always willing to assist.

Loki
Thanks for that.
Stainless is definitely the way to go IMHO.
Hopefully, I've got the master cylinder kit sorted.
Bought a repair kit from Wemoto.
It was originally intended for a GL1000, but apparently it will work.
Unfortunately it was the last one in stock.
I've noticed that a lot of these parts suppliers are absolutely determined not to give away the actual maker of the pattern parts they supply, or the makers own part number.
If it actually works, I'll post the parts number on here for people's reference
 
Just realised I gave you the caliper details but they do a kit for the master cylinder as well, good quality, I've just done mine, waiting for new hoses to come maybe tomorrow and I can get the rear brake filled and bled.

Loki
 
Just realised I gave you the caliper details but they do a kit for the master cylinder as well, good quality, I've just done mine, waiting for new hoses to come maybe tomorrow and I can get the rear brake filled and bled.

Loki
I've already bought a kit from Wemoto, and ripped myself off in the process.
Kit looks like cheapo Chinese junk but fingers crossed it should be OK.
I've got one spare master cylinder ready and another one finally in the post on it's way to me.
The one on the bike seems to have had a chunk ripped out of the lip that retains the dust boot, so I'll avoid using it unless I have to
 
I got all the brake kits from Wemoto for the VFR750 I restored last and they seemed good quality Japanese make, all worked well with no leaks, it just went through MOT with a clean bill of health so I must have done something right!

Loki
 
One I did earlier


BE3C1567-B4F8-476F-9421-64291BC996A7.jpeg
 
That's the colour I had, about 25 years ago. Convinced myself I needed a sportsbike and swapped it. I paid the price on comfort until about 10 years ago! Wish I still had it, made a nice noise. 👍 Honda made some great bikes in that era, FireBlade, CBR 6 and the FireStorm.
 
Just got the rear caliper and master cylinder that I was waiting for.
To my amazement, the master cylinder is still free, although it's debatable whether it will be OK to use as is.
The fluid has been tipped out by the looks of it, so I'm assuming the caliper is probably seized, but even so, it gives me a full set of pins, shims, and the cover plate, which were all missing from my bike.
Maybe I'll get away with just new seals and dust boots on the caliper ?
20250607_152156.jpg
 
I've already bought a kit from Wemoto, and ripped myself off in the process.
Kit looks like cheapo Chinese junk but fingers crossed it should be OK.
I've got one spare master cylinder ready and another one finally in the post on it's way to me.
The one on the bike seems to have had a chunk ripped out of the lip that retains the dust boot, so I'll avoid using it unless I have to
We have the same wemoto in oz and they dont sell original parts . I did my F2 brakes and masters with their kits . I got all stainless pistons and nipples , The only trouble I had was the front master seal swelled after 2 years of being rebuilt but not installed and bled . Had to get a new seal kit after I figured out what was going on . Man did prices go up in just 2 years !
 
Now I've got one potentially good rear master cylinder, and one previously seized one, with a new repair kit.
Looking at the rear caliper, I've ordered stainless steel pistons with new piston seals, less than £50 for both.
I've got new rear pads, hopefully all the pins and shims.
I've even got a joint seal on order which seals the caliper halves together.
What I can't seem to find, is the dust boots for the pistons.
Honda part no. 43207-371-006.
Probably a GoldWing part .
Anyone sell them, or something that will substitute ?
 
The moving parts of the Goldwing calipers are identical so pistons seals etc. are the same but that's it, if you're missing any no longer available parts you might have to buy another caliper just to get the parts you need, this is what I had to do to get the spring clip that goes between the pads.
If your master has been stored with fluid in it you should be good to go although you may need to polish the entrance of the cylinder a bit before you can get the internals to go in, the non return valve in the bottom of the cylinder can be a bit tricky to get out as well.
Got my rear brake assmbled and fitted to the bike, filled with fluid and bled through and now I have a solid rear brake, had to use a vacuum bleeder to get the fluid into the caliper then it bled without any issues, just pumping the brake pedal did nothing.

Loki
 
If I'm filling a system from empty, I remove the caliper from the disc, then tip it up, so the bleed nipple is the lowest point in the system. Then I use a medium size syringe, like you can get for turkey basting in a cook shop. I put a short plastic hose on the syringe, prime it with brake fluid and connect it to the caliper bleed nipple. Open the bleed nipple, then slowly empty the syringe into the system, to the point the top reservoir is 1/4 full. Tighten the bleed nipple, top up the reservoir and I'm good to go.

A slow smooth action on the syringe ensures the air stays above the brake fluid as the level rises. I do check for air in the usual way, but never had any with this method.
 
Today I have removed the rear master cylinder from my F1.
Previously I'd managed to strip down a spare seized one that came in a box of rusty bits.
And also bought another spare one (possibly off a GoldWing) that was still free.
I was amazed to see what some clown had done to the unit still on the bike.
There was a small chunk of metal broken out of the rim that retains the internal circlip.
This was because the circlip had been forced out and removed along with the retaining washer.
I didn't realise until I cleared away the crud, and the piston assembly fell out.
Then the master cylinder had been apparently returned to service, with only the pressure from the operating rod keeping the internal parts inside.
Some people should really be physically restrained from messing with anything mechanical
 
Today I have removed the rear master cylinder from my F1.
Previously I'd managed to strip down a spare seized one that came in a box of rusty bits.
And also bought another spare one (possibly off a GoldWing) that was still free.
I was amazed to see what some clown had done to the unit still on the bike.
There was a small chunk of metal broken out of the rim that retains the internal circlip.
This was because the circlip had been forced out and removed along with the retaining washer.
I didn't realise until I cleared away the crud, and the piston assembly fell out.
Then the master cylinder had been apparently returned to service, with only the pressure from the operating rod keeping the internal parts inside.
Some people should really be physically restrained from messing with anything mechanical
Especially brakes!!

Loki
 
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