Author Topic: '78 750K first project by a car guy... (Read 34075 times)

Stev-o · « **Reply #75 on:** October 11, 2015, 05:37:07 PM »

Nice polishing! Why shorter spring?

I installed Progressive springs in my K4, it comes with a spacer you can install to adjust preload.

RandyBMC · « **Reply #76 on:** October 11, 2015, 07:38:16 PM »

Being new to bikes, I have to admit some ignorance. I thought to lower the bike's front, you would need a shorter spring (similar to how you lower a car). I didn't want to lower the bike by just moving the forks up in the triple, as I thought you would lose travel that way.

So I guess a question is in order - what's the proper way to lower the front of the bike? And is that advisable for handling (I was under the impression that lowering the front and having rake improves turn-in)?

Stev-o · « **Reply #77 on:** October 11, 2015, 07:51:49 PM »

You could shorten the tubes to lower the front end but I wouldnt do that.
I suggest getting the bike put together, running and riding safely, then upgrade the suspension as you see fit.
Unless you are an advaced rider and plan to carve canyons or track it, I think you'll find the CB a fairly good handling vintage bike.
However, replacing 35+ year old springs and shocks is a good idea.

RandyBMC · « **Reply #78 on:** October 11, 2015, 08:28:17 PM »

Exactly - so I figured while I was going to replace them, I would make it handle as best as possible with the stuff I'm buying.

Great advice though! I agree and that's my plan. Make it all work, then tweak. But if I am changing it out anyway, what should I use...

RandyBMC · « **Reply #79 on:** November 05, 2015, 11:12:20 AM »

I've been doing lots of odds and ends waiting for o-rings.

I wire wheeled the whole frame in prep for the chassis paint.

I also went shopping! Lots of goodies have been arriving. I got new All Ballz bearings for the wheels and the neck, as well as fork seals. My ignition was a butcher job, and it didn't have a key, so I bought one of those. Speaking of butcher jobs, I went ahead and bought a new wiring harness, as the old one had a combo of splices, solder, duct tape (no kidding), and crimps that made me cringe a bit. I got new coil packs and condensers too. I bought new swing arm bushings, rear shocks and Progressive front springs as well (those haven't arrived yet). I also bought a polished engine bolt kit from Alloy Bolts. My brake handle was broken, so I got one of those along with the front brake wiring switch. I also needed front fork seal retainers and the seal to rebuild the caliper. The stuff really adds up!

I received the seat - decided to go with a Tuffside and I am really happy with the decision. I hooped the back and it turned out well I think.

I also inserted the brass bushings into the swing arm.

I rebuilt the front caliper and installed a new bleeder. I also polished it (along with a few other items).

I am now waiting for water to boil to try to get the pesky fork seal removed. Work continues...

SOHC4 Cafe Racer Fan · « **Reply #80 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 #81 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 #82 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 #83 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 #84 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 #85 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 #86 on:** November 15, 2015, 01:29:09 AM »

Thanks!

RandyBMC · « **Reply #87 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 #88 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 #89 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 #90 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 #91 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 #92 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 #93 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 #94 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 #95 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 #96 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 #97 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 #98 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 #99 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.

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Author Topic: '78 750K first project by a car guy... (Read 34075 times)