Author Topic: '78 750K first project by a car guy... (Read 34500 times)

SOHC4 Cafe Racer Fan · « **Reply #75 on:** November 05, 2015, 12:07:14 PM »

Yes, new parts do add up. Don't keep a running tally unless you want to cry or have your sig other see it!

Stev-o · « **Reply #76 on:** November 05, 2015, 03:13:07 PM »

Going crazy buying parts, I love it! Seat does look good.

I use a real small c-clamp to remove the fork seals.

Restoration Fan · « **Reply #77 on:** November 05, 2015, 05:03:43 PM »

I like the seat, Randy! And the shiny bits look great.
Now comes the fun part. As you start to see it all come back together, there really is no way to describe that to someone who hasn't done it. Keep up the good work!

RandyBMC · « **Reply #78 on:** November 07, 2015, 12:30:18 PM »

I tired the c-clamp and it just kept coming through the seal, if that makes sense. I ended up hitting them with PB Blaster, boiling them and using a rag and a really big screwdriver and they popped out. Not easily, but clean with no damage to anything.

Just refurbed the oil tank - wire wheeled it and welded up a pin hole I found. Then I painted it with the same semi-gloss I used on the engine.

My o-rings finally came! Now the engine assembly can continue...

RandyBMC · « **Reply #79 on:** November 13, 2015, 09:09:15 AM »

Lots of progress - photos to follow. I have a quick question though.

I just rebuilt the forks with new Progressive springs. This is a '78 remember. I replaced the fork seals with an All Ballz kit, which is right, because it has the 77-78 dust caps in the kit. Once I pushed the new seal all the way down to the stop on the lower, there was some space to the retainer ring. So the ring doesn't sit right on the seal. The seal is bottomed, and the retainer ring is in the correct place. Is this right?

Stev-o · « **Reply #80 on:** November 13, 2015, 04:38:28 PM »

My K4 was the same, Randy. Don't know why but no issue. The seals won't move...

RandyBMC · « **Reply #81 on:** November 15, 2015, 01:29:09 AM »

Thanks!

RandyBMC · « **Reply #82 on:** November 19, 2015, 09:13:59 AM »

I have rebuilt the brakes on the front (master cylinder and caliper), but the switch I ordered from CB750Supply is just the wire, not the mount. The part, 35340-393-771, is NLA from the Homda suppliers. The only place I can find it is CMSNL, which is far and in Euro (Holland I think).

Does anyone know of another part number that retro-fits, or if there is another work around? Is this switch a starter safety switch as well, or just for the brake light? Also, can a hydraulic inline switch be used in lieu of the electric switch and just mount that at the master cylinder before the brake line (and if it is a starter safety switch, will that work)?

Thanks in advance for all of the help - this forum has been a life saver.

RandyBMC · « **Reply #83 on:** November 19, 2015, 12:31:32 PM »

So digging further, it looks like the master cylinder on my bike is an early unit. The only way I figured that out was that the brake lever I received from CB750Supply didn't fit, so I pulled out the parts book to look at the differences. Mine is flat, and the new part has a raised lip around the bolt hole on both sides, which looks right for the '78. Since the new part doesn't fit mine, I think the master cylinder I have is the early unit.

That means I need to figure out a brake switch - I am thinking the hydraulic unit through the banjo bolt at the master cylinder. The brake line that was on the bike is one long line into the hard line, like the '78 is supposed to have.

So the question is still can I use the hydraulic switch on my harness? Has anyone done this, and how did you make it look clean if you did? The boot won't fit over the end with the switch if it goes on the way I think it does.

Also, does anyone have any detailed shots of an early master cylinder and a 77-78 master cylinder?

RandyBMC · « **Reply #84 on:** November 19, 2015, 06:59:16 PM »

Here is the lever style I have:

And here is what a '78 should have I believe (and what I bought from the World Wide Web):

So I'm thinking of buying one of these hydraulic brake switches:

And it would be mounted directly at the master cylinder (through the banjo) instead of at the tri-plug from the early models. That's what I'd like to see how others have done before. The rubber boot that goes over the banjo can't fit with the switch in place, and I'd like to figure out how to make it clean.

I also saw a really cool tank that was along the same lines as what I want for my paint scheme. I am thinking more gloss grey than silver, and black or blue for the stripe with black or white outlines, but it shows the look:

And finally, the engine all assembled - I'm really digging it...

Restoration Fan · « **Reply #85 on:** November 19, 2015, 07:08:27 PM »

The 2nd picture is the one for the 78.
I just went out and removed my clutch lever to take a photo of it.

Also, that hydraulic brake switch looks like the ones for a 550. On my 78, I don't need the hydraulic switch for brake lights. There's an electronic switch inside of the brake assembly that is triggered when the brake lever is pulled.

The engine looks gorgeous, too. Really nice work.

RandyBMC · « **Reply #86 on:** November 19, 2015, 07:20:19 PM »

Thanks man.

Yeah, I definitely have an early master cylinder then. No electrics. And the '78 MC is like trying to find hen's teeth, so I plan to use what I have - just need to figure out how to trigger the brake light without the early brake line set up. Any input from anyone is gladly accepted....

Restoration Fan · « **Reply #87 on:** November 19, 2015, 07:31:55 PM »

The hydraulic line would work fine if you have to go that route. But if you do, then you're going to have to match up the lower line from that hydraulic switch down to the caliper. You won't be able to use your standard 78 brake line.
Check with Bill Benton to see if he has a 77 or 78 MC and brake assembly. I'll bet you money he does.

Stev-o · « **Reply #88 on:** November 19, 2015, 07:32:33 PM »

Engine looks fantastic, Randy. What's the status of your frame?

Don't have an answer about the switch, but if you want a clean look, may be best to get the '77-78 MC.

http://www.ebay.com/itm/1977-Honda-CB750-750K-416-Front-Brake-master-cylinder-/271241098367?hash=item3f273ab47f:g:WssAAOxyrxZR1LWt&vxp=mtr

RandyBMC · « **Reply #89 on:** November 20, 2015, 12:26:08 AM »

The frame is in the background of one of the photos - I've been doing lots of little things and need to finish up the frame prep before painting it. I cleaned up the battery box and painted that, worked on the wiring harness (but haven't finished), sanded and painted the headlight bucket, refinished the lower triple, finished the forks (with new seals and the Progressive springs), I replaced both condensers on the ignition plate, and of course the front brakes.

I still have a few big items, and a whole bunch of little things. Next biggie is probably rebuilding the carbs, then paint the frame, then mate the engine to it, then...

As far as the MC goes, because of the rarity, I'm betting whoever has one wants big $$, and I have one that works. I'm thinking maybe the bolt for the hydraulic switch will fit under the boot, then I can just run the wires out under the brake line and zip tie it along the hydraulic line?

Stev-o · « **Reply #90 on:** November 20, 2015, 05:54:04 AM »

I haven't done it but I'm sure others have or have a better solution. Start a thread in the tech section, you should get better exposure to get an answer.

madmtnmotors · « **Reply #91 on:** November 20, 2015, 06:21:54 AM »

Quote from: RandyBMC on November 20, 2015, 12:26:08 AM

I'm thinking maybe the bolt for the hydraulic switch will fit under the boot, then I can just run the wires out under the brake line and zip tie it along the hydraulic line?

Sounds like that would work. The wires from the stock switch would follow the brake line from under the master cylinder, so what you have proposed sounds like the cleanest solution. I'll have to make a mental note of this should any of my 78's suffer a similar fate.

Restoration Fan · « **Reply #92 on:** November 20, 2015, 07:42:37 AM »

Quote from: RandyBMC on November 20, 2015, 12:26:08 AM

As far as the MC goes, because of the rarity, I'm betting whoever has one wants big $$, and I have one that works.

If Bill has one, I think you'll find his prices more than reasonable. He has about 60'ish of these bikes plus literally rooms filled with boxes of parts. He's a fantastic guy and an active member on the board. Bill/BentON Racing is his user name on the forum.

Send him a PM and ask what he wants for one. It can't hurt to ask.

RandyBMC · « **Reply #93 on:** January 20, 2016, 09:54:55 AM »

So I set the gaps on the points, did a static timing set up all in preparation to install the engine in the frame. I had wire wheeled the entire frame and then painted it with POR15, and I like the way it turned out.

Before putting the cam cover back on for good, I checked the cam timing one last time. This is what I see. The piston is at TDC and the timing plate confirms that too (as does a 1/4" extension in the plug hole as I rotate the crank). This looks like less than a link to me on the cam chain.

What does everyone think - pro opinions? Is this "close enough"? Options besides an adjustable cam sprocket if it isn't? Can I just pull the tensioner out and leave the rockers in place, or can you not set timing with the valve spring tension?

ASAP please! Thanks for your help!

Randy

RandyBMC · « **Reply #94 on:** January 20, 2016, 01:54:09 PM »

Got it sorted. It was exactly one link off. I backed off all of the rocker arm adjusters (for setting the valve clearances), pulled the chain tensioner, then pulled the sprocket and reset the cam timing. More photos of the frame to follow.

RandyBMC · « **Reply #95 on:** February 11, 2016, 11:59:58 AM »

So some photos of the progress. I've been working at it a lot, but just haven't sat down to upload all of the photos.

Here is the frame - bare metal, frame off restoration!

Got my new tires too. I've since mounted them as well.

Did the All Ballz bearings and installed the triple tree.

I used the proper tool and it worked out pretty easy (you can see it laying on the floor).

I pulled the engine off of the stand and mounted it in the frame using the "lay it on its side" approach. Much easier than pulling it!

Then I started work on hanging the suspension. It goes so much easier building with nice clean parts compared to pulling junk out of baskets or getting rusted parts off!

I rebuilt the left and right controls, which looked atrocious, and now they feel like new! I don't have many photos of that, since I used the forums here to do the assembly/rebuild. I'll have to take a couple of the finished products. You can see the left control in this photo, along with my current work - ELECTRICAL!

Here is the battery box - I am waiting for the new ATC/ATO fuse box from Hondaman, but I have a couple of bits from Rick's on there now. I'm making a top bracket for the R/R to fit the stock voltage regulator mount.

Now a request for some advice. I bought the coils from one of the CB750 specialists, but the mounts had the hole oriented sideways. I have made it work, but the coil orientation is different. Does anyone see any issues with this?

Last night, I mounted the rear turn signals, the gauges, the rear shocks, and hung the rear wheel. Photos to follow.

madmtnmotors · « **Reply #96 on:** February 11, 2016, 12:43:40 PM »

Quote from: RandyBMC on February 11, 2016, 11:59:58 AM

I pulled the engine off of the stand and mounted it in the frame using the "lay it on its side" approach. Much easier than pulling it!

LOL!

Nice job on the C-hook, but your lifting lug at the top is oriented 90 degrees off. If you rotate the loop at the top 90 degrees (or add another loop between the lifting lug and chain hook) then the hoist comes in from the side of the bike instead of the front, like this:

Of course, when the bike is striped to the frame, then the lay-down method works fine. I have had to pull several engines that did not require the full "frame off" treatment, so the lay-down method is not always practical. It only took me ten minutes, working alone, to wiggle the engine into the frame in the pictures above, and it only took that long because I had to stop to take pictures.

RandyBMC · « **Reply #97 on:** February 11, 2016, 01:38:49 PM »

Hey Wilbur,

Yeah, I just used the hoist to pull it off the engine stand, so the orientation didn't matter. I turned it around when I used it to pull the engine out - which I think I have pictures of in this thread somewhere (it actually is oriented correctly as long as I flip it around).

The "lay it on its side" worked great to keep everything scratch free! If I need to pull it for something once the bike is together again, I will certainly use the hook again. It's a great shortcut!

madmtnmotors · « **Reply #98 on:** February 11, 2016, 01:54:38 PM »

Ahhhh... that sounds better!

RandyBMC · « **Reply #99 on:** February 12, 2016, 09:29:36 AM »

Got some new bits from Dime City. My turn signals, gauges, fuel line and filter, and my Bates style tail light.

I started with the rear turn signals, using Adel clamps, which have rubber isolation for vibration damping, which I thought would be a slick way to mount them. Initially, I went with this set up:

Then I mounted up the rear wheel (which in itself is pretty exciting), and realized that I wouldn't be able to get the same clearance as the rear suspension compressed as I should. Easily fixed by swapping the clamps around so the flat part was out instead of in:

You can see the gauges in that photo too, but I didn't like the mounting solution - they looked too far apart to me. So I used the DCC bracket, which meant I had to relocate my choke cable. I mounted it in the original gauge mount hole, and I think it turned out pretty clean. I am going to get a stainless hex stud to put in the old hole to make it look a little more finished.

I am now thinking of mounting the front turn signals with the headlight bucket. This is the factory bucket, but I also have a slightly larger "British style" bucket that I would like to use. It has non-metric threads though, so I need to drill and tap that bucket if I want to go this route with the turn signals.

A couple more shots with the rear wheel on.

I then disassembled the horn and refinished it. The chrome was unsalable, so I wire wheeled it, sanded it down and hit it with POR15 Top Coat. It came out nicely. I had to install new wiring as well, as the PO had snipped them right at the base of the horn. It looks nice all mounted up.

I then reinstalled my refurbished center stand. Originally I was only going to use the side stand I snapped up and refinished, but until I get it sorted, I think I'm keeping the center stand.

I installed the rear shocks too!

Now it is on with the wiring process, and finish up the front end. Having never done motorcycle carbs, I am debating whether or not to tackle the PD42s myself or send them out for a pro... I have rebuilt Webers for old Porsches in the past, but these are smaller and I'm older! Advice from those who have been there and done it?

News:

Author Topic: '78 750K first project by a car guy... (Read 34500 times)