Author Topic: 1975 Honda CB750 F Supersport Restoration (Read 4879 times)

NickRafAcosta · « **on:** March 11, 2018, 04:19:20 PM »

Recently got my hands on a fairly good condition 1975 Honda CB750F model, will definitely need some tlc to fully restore it to stock form, however I'm trying to figure something out. On a few photos of early CB750F's there is some sort of black box beside the horn attached to the front of the frame. I don't have it on mine and I'm trying to figure out what it is and where I can get whatever it is to bring mine back to factory stock
Nick

ofreen · « **Reply #1 on:** March 11, 2018, 05:03:14 PM »

That is a junction box packed with a gob of wires and their connectors. This example sports the factory approved black electrical tape modification.

Jerry Rxman Griffin aka MuthaF'er · « **Reply #2 on:** March 11, 2018, 11:49:14 PM »

Greg, did you steal my taped box picture??

The "hinges" have a tendency to break after a while thus the factory approved electrical tape repair.

ofreen · « **Reply #3 on:** March 12, 2018, 04:49:03 AM »

Quote from: Jerry Rxman Griffin aka MuthaF'er on March 11, 2018, 11:49:14 PM

Greg, did you steal my taped box picture??

Your bikes never look that scroungy. I need to clean the poor old thing.

Stev-o · « **Reply #4 on:** March 12, 2018, 08:22:11 AM »

I have a spare black box if anyone is in need. Sold my Effin F a couple years ago...

NickRafAcosta · « **Reply #5 on:** March 12, 2018, 07:00:55 PM »

Well looks like a need a box then! I checked the bike today and I have the mounting brackets still on the front of the bike for the junction box thankfully, But No Box!! Seems that all the electrical was stuffed beside there to fit a old oil cooler in the front. On top of it, a few more mysteries have popped up. The rear master cylinder seems to have been replaced, and i think the rear brake switch too, photos attached to help visualize my problems! If any of you can help with locating these missing items and where i can buy them it would be greatly appreciated!
Nick

marccrabtreee · « **Reply #6 on:** March 12, 2018, 07:42:07 PM »

Partzilla https://www.partzilla.com/catalog/honda/motorcycle/1975/qa50k3-a Sturgess Cycle http://www.sturgessonline.com/fiche_section_detail.asp?section=2451441&category=Motorcycles&make=Honda&year=1975&fveh=131093

#43500-392-622 (replaces 43500-392-672) Rear Master Cylinder

#32400-392-000 Wire Harness Box

Jerry Rxman Griffin aka MuthaF'er · « **Reply #7 on:** March 13, 2018, 11:12:38 AM »

Looks like you're getting a good handle on all of these things. No real way to mount an oil cooler like that without doing something (remove/relocate if possible) with the junction box. The mount tab with the 2 holes is bent backwards. Should point forward. And yeah, the rear master is not stock. Does it work? Do you want stock? Kinda difficult to find a good one. If you do go stock plan on getting a rebuild kit in all likelihood plus the brake switch with mount and spring too.

NickRafAcosta · « **Reply #8 on:** March 13, 2018, 07:11:42 PM »

No unfortunately the rear master cylinder isn't really working right now, I would prefer to use a stock one but I could settle for an aftermarket one if need be. I can also bend back the mounting tab for the junction box and hopefully order a new one so I can fix up the front properly, the oil cooler is currently mounted where the front horn used to be so ill have to fix that too but as far as I can see none of the old mounting tabs have been cut off, only bent. If anyone can provide pictures of the stock rear master cylinder setup, rear brake light and spring, and most importantly the front junction box mounting and how it looks on the inside that would be greatly appreciated! Hoping to have this bike all fixed up by the end of april since riding season should start by then here in Toronto.
Nick

seanbarney41 · « **Reply #9 on:** March 13, 2018, 08:12:07 PM »

Here ya go, best I could find...please note my bike uses cb400f foot pegs and a custom brake pedal.

KIMG0103 by Sean Barney, on Flickr

There are lots of Honda masters that will fit and function with little or no modification. 76f will be identical but all aluminum body/no plastic, 77/78f will bolt right up but uses a remote reservoir like the one you have. Early gl1000 also bolts right up but you will need an adapter for the brake line...I think there are many more from the early eighties that can work, just look for that diagonal mounting bolt pattern when browsing ebay.

Jerry Rxman Griffin aka MuthaF'er · « **Reply #10 on:** March 14, 2018, 12:40:36 PM »

I can more easily TEXT whatever pictures you might need EXCEPT TO CANADA APPARENTLY? If needed just send me your phone number.

kap384@telus.net · « **Reply #11 on:** March 14, 2018, 07:53:40 PM »

Awesome to see another 'F' being saved!

josherr · « **Reply #12 on:** March 16, 2018, 05:32:41 AM »

I suggest going with a aftermarket rear master, I went through three and none of them worked properly
It’s rare to find a good one

Sent from my iPhone using Tapatalk

josherr · « **Reply #13 on:** March 16, 2018, 05:41:23 AM »

Here’s some pics I found when I was trying to set up the rear

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NickRafAcosta · « **Reply #14 on:** March 17, 2018, 07:35:03 AM »

Thanks for the Advice, which aftermarket master cylinder assembly would you suggest that would fit my 75 supersport?
Nick

Bankerdanny · « **Reply #15 on:** March 21, 2018, 02:24:01 PM »

Quote from: ofreen on March 11, 2018, 05:03:14 PM

That is a junction box packed with a gob of wires and their connectors. This example sports the factory approved black electrical tape modification.

Mine has the aftermarket zip tie upgrade

Bankerdanny · « **Reply #16 on:** March 21, 2018, 02:27:03 PM »

Quote from: josherr on March 16, 2018, 05:41:23 AM

Here’s some pics I found when I was trying to set up the rear

Lots of old F bikes sporting Kerker mufflers. Mine has the same one and it looks that good from that same angle, sadly it is rusted through on the tire side and not salvageable.

NickRafAcosta · « **Reply #17 on:** June 03, 2018, 12:20:39 PM »

REVIVING THIS THREAD!
Finally have the time now to restore this beautiful machine, Will post more pictures soon.
I was just stripping the frame today to get it ready for paint, and removing all the old sidecar mounts, and I noticed this mound right beside the oil tank area. Now I'm sure that's not stock, and someone welded something terrible there once upon a time. Any thoughts anyone? I'm afraid I will have to simply spend all day with my angle grinder grinding it down
Nick

Jerry Rxman Griffin aka MuthaF'er · « **Reply #18 on:** June 03, 2018, 03:19:06 PM »

Correct, that is NOT stock.

NickRafAcosta · « **Reply #19 on:** June 04, 2018, 06:48:59 PM »

Day 2
So after work today all these nasty sidecar welds and whatever was welded onto the oil tank area were all ground off, frame is pretty much stripped now and ready for a nice fresh can of Eastwood Chassis Black. Trying to figure out a way to bend the Horn mount to its normal straight position, if anyone has a suggestion I'm all ears, I was personally thinking of trying to get a small vice and clamping it back straight but clearance is a bit of an issue
Nick

calj737 · « **Reply #20 on:** June 05, 2018, 03:10:03 AM »

Cut if off, heat it up with O/A, then flatten it. Weld it back on. 30' job.

If you can't weld, then heat it up in place, screw a thick plate to and CRANK down on the screw. Add more heat. Let cool in place. That will help straighten it. Be sure to use some Antisieze on the screws or other release agent. And DON'T use stainless screws during the heating process. The heat will fuse them to the threads permanently.

70CB750 · « **Reply #21 on:** June 05, 2018, 03:29:02 AM »

Quote from: ofreen on March 11, 2018, 05:03:14 PM

That is a junction box packed with a gob of wires and their connectors. This example sports the factory approved black electrical tape modification.

So they stopped stuffing all the wires in the headlight shell? Amazing

NickRafAcosta · « **Reply #22 on:** June 22, 2018, 05:33:40 AM »

UPDATE!
So recently painted the engine, frame, and gas tank back to stock, and while putting the bike back together I seem to have forgotten how the centre stand stopper precicely goes on! I think I got it, but if anyone can confirm i got it right it would be greatly appreciated!
Nick

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Author Topic: 1975 Honda CB750 F Supersport Restoration (Read 4879 times)