Topic: Reviving a '73 750

[PeWe]

I should not trust neither handling, wear, grip in dry as wet and braking capabilty with tire rotation wrong.

[Kevin D]

I should not trust neither handling, wear, grip in dry as wet and braking capabilty with tire rotation wrong.

I’m not an Avon user or a tire engineer. I like to do things as right as I can, to give myself every advantage when I’m on the road, and the chips are down.
I saw an unusual marking on your front tire gpzkat, couldn’t make out the arrow marking on the rear, so I went to the Avon website and read a bit about inverted front grooves.

https://www.avontyres.com/en-us/tyre-care/technical/tyre-technical-symbols/

[SOHC4 Cafe Racer Fan]

FYI - I like the grip of Avon RoadRiders, but at least here in California, when you ride them on a grooved concrete (freeway) surface at highway speed, they feel like they track the grooves so that the front may meander. 

A few friends have told me that they have experienced the same thing.  I'm not sure that it matters, but everyone who had the issue was running a front fork brace on their bike (CB750, CB550, air-cooled Triumph Thruxton).

[gpzkat]

Thanks for concern and eyeballs, will remount.  I'm down to a handful of things left, and will add this to the list. 

I have Roadriders (not v II though) on my GS1100E and like them a lot,  but haven't ridden all that much and no freeway yet - regarding grooves.  My first encounter with groovy wallow was in '83 an '82 GS1100E, riding through Houston TX on my way to Florida.   Pretty bad, they were the stock 'Mag Mopus' tires.   I rode 1100 milies that day and it is the only section of the ride I really remember other than the long bridge in Louisiana where I pegged the speedo - at 85mph of course, that's redline in 5th right? 

[Davez134]

FYI - I like the grip of Avon RoadRiders, but at least here in California, when you ride them on a grooved concrete (freeway) surface at highway speed, they feel like they track the grooves so that the front may meander. 

A few friends have told me that they have experienced the same thing.  I'm not sure that it matters, but everyone who had the issue was running a front fork brace on their bike (CB750, CB550, air-cooled Triumph Thruxton).

I had the same experience here in Vegas with those tires. Never felt it before. It was very unnerving. They got better with wear, but still feel it a bit on the grooved freeways.

[gpzkat]

The back is done except for the chain. I have a D.I.D. non O-ring that came with the bike, it's new in its box so I'll try it out.  Still liking this blue on the loaner side cover.  Not the right color for a '73 but I'm not that concerned about it, as it's not show quality, just a clean rider.  I'm leaning toward it.

[wolf550]

can't wait to see the finished product.
finishing up the last bits and pieces of my frankenstein over here.
might have to take it out of Non-Op just to ride something around here.

[gpzkat]

I'm down to just a few things, wired it up and everything lit up and worked right - for a while anyway, then poof, nothing.   I hooked up a jumper to the 5A and 7A lighting circuits and it works, no short going on.  I checked ignition and it seems fine, but since it was pretty stiff I took it apart to clean and lube it.  I'll go through each section next with meter and jumper, will figure it out. Suspect the switch at this point or possibly a loose connection inside the fuse box.

can't wait to see the finished product.
finishing up the last bits and pieces of my frankenstein over here.
might have to take it out of Non-Op just to ride something around here.

[gpzkat]

I put '72 lower rise bars on my '73 bike and bought a Motion Pro 02-0005 clutch cable (d'oh!) that's too long. There's no way to tuck it into the down tubes without a big bend in the cable and it sticks out like dog nuts, as the Aussies say.

The same OEM number 22870-341-010 comes up on Partzilla for both '72 and '73, but '71 shows  #22870-300-000 which I'm suspecting is shorter.  Sites like Z1 parts show they are the same but I sort of doubt it.  Anyone else do this? lower bar mod?  I want it to be right.  I will search some more, the length would be good to know.   Otherwise I guess I could modify the cable but cables aren't expensive an I don't want the hassle.

[newday777]

I'm down to just a few things, wired it up and everything lit up and worked right - for a while anyway, then poof, nothing.   I hooked up a jumper to the 5A and 7A lighting circuits and it works, no short going on.  I checked ignition and it seems fine, but since it was pretty stiff I took it apart to clean and lube it.  I'll go through each section next with meter and jumper, will figure it out. Suspect the switch at this point or possibly a loose connection inside the fuse box.

If the fuse was an original, it could have been weak and failed. I had the old fuse fail out on one of my 1st rides of bringing the 75 back to life after it's 12 year sleep. I was down shifting to a red light and all went dark. I pushed it over to a parking lot and found the main had blown. Thankfully had a spare. I ordered new fuses from Honda as local were all the longer USA spec fuses. Old fuses get weak and fail.
BTW I've always been fond of the 75 Planet Blue. I had bought one new in 75, lost it to my ex cousin totaling it. I have another now.

I plan to change out these 10" bars to the lower 72 euro bars, so I'm interested in the correct cables to get also. These 10" bars have been on since the 1st owner put them on when I was parts manager in 76. Time for a change.....

[gpzkat]

Thanks - yeah I had a bunch of old Buss fuses, I keep everything... so I tried different ones etc.  And yes, they are longer like you say.  I remember in the old days a foil chewing gum wrapper would be used temporarily.

I figured it out by jumpering the wires, the ignition switch tested OK with the ohm meter but with a load it wouldn't pass current.   I took it apart before and could see a pretty worn contact, so I tried sanding the thing down.  Weird because it's a spring loaded contact and seemed simple, but my tests definitely showed it doesn't do the job. The circuit is really simple so I know it's the issue.  At about $15 I just bought a new switch.

Low bars and planet blue do the trick for me. I will update once I get the right cable.

If the fuse was an original, it could have been weak and failed. I had the old fuse fail out on one of my 1st rides of bringing the 75 back to life after it's 12 year sleep. I was down shifting to a red light and all went dark. I pushed it over to a parking lot and found the main had blown. Thankfully had a spare. I ordered new fuses from Honda as local were all the longer USA spec fuses. Old fuses get weak and fail.
BTW I've always been fond of the 75 Planet Blue. I had bought one new in 75, lost it to my ex cousin totaling it. I have another now.

I plan to change out these 10" bars to the lower 72 euro bars, so I'm interested in the correct cables to get also. These 10" bars have been on since the 1st owner put them on when I was parts manager in 76. Time for a change.....

[gpzkat]

My front fender was more faded and pitted than I liked, so I found one with excellent chrome for $20.  Well something similar.... The seller wasn't sure exactly what it was for, said CB450 and CB550.   I went to look at it and realized it wasn't the same bracket (450 I think), but the fender itself is the samee.  I have ground out the rivets to swap the bracket.  It will be great, I just need to either have it buck riveted back or maybe screws will work.   

I also found a package deal on parts including really good original shocks, rear fender, grab rail, battery box and complete electrics attached plus a new battery.  So I have some decent extras to part out now, and the stuff going on mine will be very nice.

[gpzkat]

Well, the CB450 fender worked out well. It isn't perfect chrome and has some dings, but it's much better than what I had.  For less than $25 it is a good upgrade.  I ground the rivets off and swapped brackets, used chrome allen head button screws from the hardware store and nylock nuts on the underside.  With that plus the better rear fender I am in much better crhome shape and have some decent parts to sell off. 

[HondaMan]

Lookin' good!

[newday777]

Lookin' good!

Ditto!

[HondaMan]

Thanks - yeah I had a bunch of old Buss fuses, I keep everything... so I tried different ones etc.  And yes, they are longer like you say.  I remember in the old days a foil chewing gum wrapper would be used temporarily.

I figured it out by jumpering the wires, the ignition switch tested OK with the ohm meter but with a load it wouldn't pass current.   I took it apart before and could see a pretty worn contact, so I tried sanding the thing down.  Weird because it's a spring loaded contact and seemed simple, but my tests definitely showed it doesn't do the job. The circuit is really simple so I know it's the issue.  At about $15 I just bought a new switch.

Low bars and planet blue do the trick for me. I will update once I get the right cable.

If the fuse was an original, it could have been weak and failed. I had the old fuse fail out on one of my 1st rides of bringing the 75 back to life after it's 12 year sleep. I was down shifting to a red light and all went dark. I pushed it over to a parking lot and found the main had blown. Thankfully had a spare. I ordered new fuses from Honda as local were all the longer USA spec fuses. Old fuses get weak and fail.
BTW I've always been fond of the 75 Planet Blue. I had bought one new in 75, lost it to my ex cousin totaling it. I have another now.

I plan to change out these 10" bars to the lower 72 euro bars, so I'm interested in the correct cables to get also. These 10" bars have been on since the 1st owner put them on when I was parts manager in 76. Time for a change.....

Hmm...if you got one of the EMGO $15 keyswitches, it will only last about 1-2 hours on this bike. They are actually CB350 twin switches (8 amp rated) being sold as CB750 (12 amp load) switches. They melt the Red wire right off the back of the switch. That's how I first created the Keyswitch Saver Relay kit for these, when we could not get the Honda switches. Today we can again, as part of a kit of the seat lock, steering lock, and keyswitch, all on one key. I've got that part number if you're interested, about $80 for the whole set.

The Keyswitch Saver Realy is just a relay that gets switched by the cheapie keysiwtch, so the relay carries the current and the switch can survive longer. But, after 5 years the tumblers all quit working in my EMGO keyswitch and the keys fell out of the ignition on the way home one night. I couldn't turn off the bike when I got home!

[gpzkat]

Thanks Hondaman - in the end it was a bad connection at the red wire coupling right off the battery, not a problem with the switch. It was confounding me as I had cleaned and prepped all connections, or so I thought.  But one can't assume, and 'to measure is to test' so I tried putting a load on the 12.7 volts I had at the ignition coupling, and it wouldn't even light up a turn signal bulb.  So I just worked backward from there.

newday777 - I got a short control cable set (SKU CCS-5) from 4into1, they are a good length for the '72 bars - within 1/2" of what I had measured and figured was correct - but the metal guide on the end of the clutch cable that slots into the aluminum clutch cover has a larger diameter, so it doesn't slot right in.   Damn, must be a year to year difference and I bet Hondaman knows about it.  I made it work but it's not 'right' from that perspective. 

The airbox is on, and it's basically done and ready to fire up and tune.  I still have an old motion pro mercury manometer from 30 years ago that I used on a few bikes including my '76 CB750.  It has moved with me to Australia 2x and seen the world.

[gpzkat]

Got tank, no side covers yet, will have to make sure I can get this tank sealed as it has rust to treat.  Not a '73 color.  I don't care, do you?

[Shtonecb500]

looks good.

[gpzkat]

It's got a non stock drain on the oil tank, I think it is to put a tube on and make the oil change less messy. I recall on my '76, about 25 years ago, how draining the oil required the incredibly difficult task of putting a funnel underneath the drain plug 

[newday777]

It's got a non stock drain on the oil tank, I think it is to put a tube on and make the oil change less messy. I recall on my '76, about 25 years ago, how draining the oil required the incredibly difficult task of putting a funnel underneath the drain plug 

I take a piece of aluminum flashing to make a shoot formed to the frame behind the drain bolt and bent outwards away from the tank to drain it. Easier than trying to hold a funnel.

[newday777]

And yes the red looks fine...but I like red also as my 76 was Anteres Red.

[gpzkat]

Today is a good day. First start.  Took about 3 seconds on the starter and fired right up.  Ka-thunk into first but had a bit of revs.

[wolf550]

how did you brave our 78 degree cold front today?

[gpzkat]

It was tough, I tells ya, but I am made of stern Viking stock 

how did you brave our 78 degree cold front today?