Topic: Project Migoto. 1973 Honda CB750 rebuild

[20sNaRanger]

Good Evening Gents 

My good buddy Charlie, many of you know him as GnarleyCharlie, got me bitten by the vintage honda motorbike bug. All I have to say is OOOO I can't wait till it's done!

We found a 1973 CB750k for a steal of a deal on Craigslist. We picked it up and it looked like this


Charlie is a hell of a guy and a great friend. I'd never be able to do any of this without him.

That being said, he has been such an invaluable asset. IF you haven't dealt with Charlie on a personal/professional stand point. . .all I have to say is that he is the real deal. Not asking for anything than cost of parts, he is basically building the bike from frame up. Using his personal stash of parts and ordering the ones that he can't provide. This is just an awesome experience. His garage is jam packed with everything a mech boy could ask for.

We, by we...i mean 99%charlie, stripped it down to frame.


Placed new steering bearings in it...i think thats what they are called. ***correct me if i'm wrong charlie***



We were going to build a paint booth and paint it in there...but Virginia's weather hasn't been the most cooperative. I offered up the spare bedroom of my apartment as an alternative. We will be doing the primer part of the paint job tomorrow a.m.  SOOOOO excited.

I'm sure Charlie will be posting tech and spec info if anyone has any questions.


I'm excited!!!! 

Joe

[Greggo]

Welcome to the forum!  My bike would be no where as nice without the help of another forum member.  It's nice to have skilled contacts.

[gnarlycharlie4u]

YES!!! finally!

let's get this thing done already.

I'll make up the vector for your tank decal on monday.

[gnarlycharlie4u]

teaser shot:

[gnarlycharlie4u]

look what I founds: IT'S PICTURES!!!

Stripping:


Stripped:


Painted and prepped for engine install:


Motor's in:

[gnarlycharlie4u]

OH #$%*! MOARRRRRRRRRRRRRRRRRRRRRRRR PICTURES!





















The biggest problems we ran into:
1) the forks that came on this thing were off of a cb350. I didn't realize how different the fork lowers were until we went to put it all together, my later fork tubes and springs would NOT fit it.
so if anyone wants a set of freshly rebuilt and painted cb350 forks let me know

2) We planned to throw the wheels and tires from my K7 on there but didn't realize that the early and later K's had different hubs. So, after about a million different tries with different acles and spacers and drums and whatnot we finally realized the left side of the hub was larger on the K7. Probably to make up for the wider swingarm and greater offest on the later F and K bikes.
So we would up cleaning 2 sets of hubs. The hardest part of all of this and probably of the entire build was that farking bearing retainer. Using TWO spanner wrenches it still took forever to get off. Joe came to the rescue when putting it back on and helped by holding them in place with a board and his weight. The added leverage of turning the board also helped greatly.

3) The center stand spring. That thing is a mother effer. Joe also had another stroke of genius though. (see below)

for anyone wondering how the wide world of sports you get that damn centerstand spring back on... here's how:

[20sNaRanger]

Thanks for throwing those in. I saved em all off of drag and was gonna pop em in here.  u beet me too it 

[gnarlycharlie4u]

Thanks for throwing those in. I saved em all off of drag and was gonna pop em in here.  u beet me too it 

<3

[gnarlycharlie4u]

oooohhhhkay so the starter relay that was on there was definitely not from that bike. It didn't mount up where it was supposed to. So I pulled one from one of the 5 battery baskets I have laying around and swapped it out.

now the cable actually reaches and we can mount that relay.

since there are no turn signals I just wrapped up all the signal and winker relay wires and taped them off.

you were missing a #$%*ton of bullet connectors but I salvaged enough from other chopped harnesses and controls and soldered them on.
I did pretty well imo. The ends look real clean now.

I bypassed your starter safety switch by plugging the green/red from the starter directly to a green line; bypassing the clutch switch and eliminating the safety.

Just make sure she's in neutral

Speaking of which I need to fish out a set of idiot lights and scavenge lightbulbs. I'll leave that up to you when you come over.


As it stands now it looks like everything is good to go, it just needs to be bolted on.

Oh and your front sprocket is mounted and looks good.

[20sNaRanger]

awesomenessssssssssssssss

[gnarlycharlie4u]

Alright so I got the headlight issue sorted out today.

A little bit of the magic smoke escaped from the wiring harness when I accidentally dropped a wrench against the starter solenoid and regulator. whooops!

Turns out it was a combination of things;
The high beam switch was shot so I fixed the switch and cleaned the contacts. (had paint on it )
The frame ground that runs to the headlight was severed.
The fuse box was having some problems with resistance so I cleaned it up and reshaped the tabs.

I also had some issues with the dummy lights that took me a while to sort out (most of it related to finding lightbulbs).





Good ol' rates nest.




The victorious moment when I finally figured out what was going on.

[gnarlycharlie4u]

So... sorry for lack of updates. The bike is now out on the road!

...just missing a passenger footpeg and seat hinges.

incidentally if anyone can spare some seat hinges that would be awesome. I don't really have the resources to fab some up.

Since the last time I posted

• I broke a spoke on the front wheel and swapped the whole thing out for a newer one.
• all the wiring was sorted out
• rebuilt and re mounted the tach (now it actually works!)
• found that stupid little screw that holds tach cable in
• broke and replaced the tach cable (luckily I had one left)
• Tail has been mounted and pillion grab bar will be as soon as the bolts come in
• bled brakes
• mounted and adjusted the chain
• adjusted valve lash, and timing
• got it running
• Carbs have been sync'd
• flushed motor and changed the oil
• sanded, primed and painted the sidecovers and tank (several times haha)
• mounted stock bars then swapped for clubmans with bar-end mirrors
• fixed brake switch problem

There's a bunch of other stuff I'm forgetting I know but by now you are probably getting bored with the details.
So, here's some pretty pictures:








To separate the gauge halves you have to CAREFULLY pry that chrome ring apart from the bottom half of the gauge. Then the top pops off and it's just a few screws to get everything apart.
It went back together with a couple slight bends of the ring and some Hondabond in case we want to swap gauge faces later. It took me over an hour and a half to pry that ring off the first time. I don't want to do it again.



To be honest I think the sidecovers look kind of awesome like this.





and the (almost) finished product.
Sorry for the awful pics, it was raining and I was in a hurry.

[70CB750]

Love that penny trick!

[lucky]

Why didn't you paint the center stand and that center stand return spring and bracket?

Guess you could do it later. After its rusted even more?
Just seems like once you have it off and all apart would be a great time to paint the part.

[gnarlycharlie4u]

Why didn't you paint the center stand and that center stand return spring and bracket?

Guess you could do it later. After its rusted even more?
Just seems like once you have it off and all apart would be a great time to paint the part.

Well Joey's lacking in primary transportation at the moment so (despite the project name) beauty took a backseat to functionality until his Bronco is reliable.
I was going to have the centerstand and bracket powdercoated so, I didn't see much of a point in painting it then having to strip it again later.
The kickstand is getting swapped out for a different one entirely.
The spring... I'm not sure what's going to happen with that. Maybe if we're feeling frisky I'll give one of those zinc plating kits a try.

edit: the battery basket and tool tray are also just as nasty as the kickstand. They too will be swapped out for ones that have been cleaned up once we're in a position to do so.

Powdercoating takes a couple weeks or so and this bike needs to be ridden now! Once I get some spare time (and money) I'll dig out a battery basket and centerstand to send to the powdercoater so Joey can still ride this around without interruption.

[20sNaRanger]

Charlie you are the man. Thanks so much. haha and even posting up in this thread where i've been slacking. lol

hopefully the bronco will be working fine after this electrical issue gets resolved this weekend.

can't thank you enough dude.

[rickmoore24]

Nice work gents!

[lucky]

I understand now whats going on.
You will have all winter to get it looking nice.

I was wondering about one of those plating kits too. But it
says you have to buff the part after. Since it is on the bottom of the bike I would use phosphoric acid to stop the rust and paint it black.

[gnarlycharlie4u]

I understand now whats going on.
You will have all winter to get it looking nice.

I was wondering about one of those plating kits too. But it
says you have to buff the part after. Since it is on the bottom of the bike I would use phosphoric acid to stop the rust and paint it black.

I used prep and etch on it once already forever ago. it actually worked pretty well for a while but then eventually began to rust a bit.

Also that flash from the camera makes the rust look about 10x worse than it actually is. For example the exhaust collars. In normal light they look shiny and nice but under the flash you can see what looks like rust.

[gnarlycharlie4u]

alright so it's been a while since I've updated anything. I'm not even sure where to begin so I'm just going to go from here:


Joey ordered a new exhaust so I threw that on. It was a #$%* and a half but we made it happen.
If you're thinking about getting the Cycle-x super sidewinder, you really should go here and read my review / writeup first:
http://gnarlywrench.blogspot.com/2012/01/cycle-x-super-sidewinder-on-joeys-k3.html


Then I replaced that leaky tach oil seal. I hope to god it works.


Then his main jets went missing... 



Then we noticed that this^^^ (white valve) was actually caused by a cracked carb boot.
78CB750CAFE (thanks again buddy. I owe you a few beers) gave me a set from some other carbs to replace them. So...



I softened them up and re-installed them.

After it was all said and done I went to start her up and now the starter doesn't work...
She kicks over just fine, and the starter works, but I can't seem to isolate why the button isn't working.
Oh well, I guess you can't solve all the mysteries in just one post. 

[Scott S]

 Checking out your blg....it seems to me that you have WAY too much travel on the brake pedal. Are you sure the torque arm is installed properly? Shoes adjusted properly? That pedal should only move about 1/2".

[gnarlycharlie4u]

Checking out your blg....it seems to me that you have WAY too much travel on the brake pedal. Are you sure the torque arm is installed properly? Shoes adjusted properly? That pedal should only move about 1/2".

brand new shoes on there. and everything was adjusted so that it would pass inspection.
I did manage to get it adjusted so that it BARELY touches the pipes when you stand on it and will still pass inspection, but once those shoes wear down and I have to adjust that rear arm some more, it won't be able to avoid the exhaust and still pass inspection. So it's good for now, but after a bit of use I'll have to readjust the rear arm so that it's within the allowed adjustment range.

Also, I think the brake pedal is supposed to have about 1/2" of FREE play before engaging the brake. the full pedal motion is something like 15º or <3"

[Scott S]

  Maybe someone else will chime in, but I have to respectfully disagree. Three inches of travel ?!? WAY too much. Adjust the arm that the brake pedal goes on and then set up the arm on the drum so that it's pretty much at a 90 degree angle with the rod in it. You should have very little travel before the brakes engage.

[gnarlycharlie4u]

  Maybe someone else will chime in, but I have to respectfully disagree. Three inches of travel ?!? WAY too much. Adjust the arm that the brake pedal goes on and then set up the arm on the drum so that it's pretty much at a 90 degree angle with the rod in it. You should have very little travel before the brakes engage.

Like I said I already adjusted it so that there's almost no (2-3mm) pre-engagement travel by moving the break lever and break arm up a notch.
It will pass inspection for the moment like this but when that new break shoe starts to wear in, the rear brake arm will be out of the allowable adjustment level.

Where are you measuring your inches of travel from?
Ideally it should be in degrees or radians since the pedal doesn't travel in a straight line.

[Scott S]

 If I hold a tape measure at the end of my pedal, it barely moves 1/2" before completely locking up the rear brake.

  You say "It will pass inspection for the moment like this but when that new break shoe starts to wear in, the rear brake arm will be out of the allowable adjustment level." That doesn't really make sense to me....why would new shoes already be out of adjustment range?

 I think you need to remove the linkage from the drum and remove the pedal. Make sure the arm at the back of the splined shaft for the pedal is positioned properly. I think you'll have to rotate it forward, towards the front of the bike. Reattach the actuator rod on the drum and set the arm on the drum as close to 90 degrees as you can. Readjust and check it again.


 Not trying to be a dick, but the way it is in that .gif is borderline dangerous. I think you can get it much "firmer".