CB 750/550 Front Caliper

[Gromitdog]

Good Morning All
Good Evening
I brought a CB750 / Cb550 calliper unit with arm assy from Ebay, I ordered a 550 calliper overhaul piston kit from Roger at Honda classic restorations Not realising that there are a couple of difference's that Honda made to the CB750 / 550  callipers over time & models
The calliper overhaul kit I ordered had a replacement piston Dia of 37.9 mm & a depth of 33.9 mm
The calliper of the spare CB750 has a calliper piston             Dia of 42.9 mm & a Depth of 33.60 mm

Also on the spare CB750 calliper it appears the the bolt hole spacings are slightly wider than on the CB550 k3 ones fitted to my bike currently. I also thought that 750 callipers all had 8mm bleed nipples this spare calliper from Ebay has a 7mm bleed nipple

From what I have read from the internet is that the Ebay CB750 calliper I have may be from a CB750F/F1 and CB750-K7/8 ??   Does anyone know if I can fit this calliper and pads with its arm assy onto 550 k3 standard disc ??
Any advice would be greatly appreciated

Nigel

[Gromitdog]

Forgot to add picture

[Bryanj]

550 was never same as 750

[Bryanj]

Just to qualify that a bit there are 3 basic calipers on the SOHC fours.
1 has allen bolts holding the halves together from the back fits 750with the early swing mount
2 has two bolts holding the halves fitted from the outside and the later swing mount fits 400,500,550, also 250/360/500 twin
3 has two bolts at different spacing to 2 fits different later swing mount and fits later 750

I think the seals are all the same but pistons fiffer

[Gromitdog]

Hi Bryan

Thank you for your info update I was never sure if my calliper had the correct bolts / Allan bolts anyway as it seemed strange to have only 2x Allen bolts on the bike, So what your saying is if I understand you correctly that 750 calliper won't fit onto a 550 ?

Thank you for your update and useful info

Nigel

[Bryanj]

No it wont, sorry

[Gromitdog]

Hi Bryan

Thank you for update now I have a CB750 calliper and arm for sale 😄

Nigel

[Bryanj]

I bought a 500 pattern caliper complete with arm from amazon i believe, looks decent will see if i can find a link for you

[Bryanj]

Look up M Mati front caliper on amazon £72.50 complete with bracket and pads

[andy120t]

Is that the one that comes from the US? I was going the other day but couldn't see a UK supplier.

[Sesman]

This mutha.

[Bryanj]

Yes it comes from us but i paid exactly what it said and arrived quickly

[andy120t]

I ordered the Mati one lastnight. It looks so clean, no scraping and painting needed...
Can't wait for it to turnnup!

[Gromitdog]

Thank you all for your help and the various links great help I think I found the UK link via Amazon Wish I known about the brake caplier complete unit before I purchased the wrong one as a 750 will not fit a 550 as it was pointed out afterwards But every day is a learning day lets hope the front hub I got will fit 🤞

Thanks agin for all advice

Nigel

[Bryanj]

750 and 500 hubs are the same, early ones have two flats on speedo drive(only used on very early 750), later ones are perfectly round.
I believe some very early hubs are narower across where the disc(s) fit