Author Topic: 1972 CB500K - Resto-Mod (Read 31141 times)

onetruepunk87 · « **on:** May 04, 2014, 03:59:21 pm »

Hey guys, was looking around on Craigslist for a few weeks looking for a new project and I found one. It's a 1972 CB500K. It's in pretty rough shape as you can see from the pictures.

I don't really know much of the history of this bike besides the fact that it spent an undetermined amount of time left outside. The guy I bought it off of picked it up to work on as a project but never touched it more than taking the carbs off (he did buy a set of carb kits that were thrown in with the bike.) He was unsure when the bike ran last and didn't even have a key. I figured what the hell, I'm up for a challenge.

Since my CB750K is pretty much all done except for general maintenance I'm in no rush to get this on the road so I'm going to take my time and do a frame up resto-mod. I figured with the carbs already off I might as well start there. This was my first time digging deep into carbs so I took plenty of pictures and watched as many videos on disassembly/assembly as I could and it wasn't all that hard. The carbs were pretty well gunked up and as well as having one missing a main jet (the previous owner had the bowls off.) I took everything out (floats, jets, slide, needle, emulsion tube, etc.) out of them and did a pine sol dip.

onetruepunk87 · « **Reply #1 on:** May 04, 2014, 04:57:34 pm »

After soaking for a day I scrubbed the carb bodies with a bunch of different brushes to clean them up and did the same to the lids and bowls. Then I cleaned the carb bodies and the inards out with carb cleaner and blasted them all with compressed air to clear all the crap out. I reassembled the top end of the carbs so far and polished the lids and bowls. I've got to order new hardware before I finish putting it all back together. The screws were way to rusted to save. I didn't want to lose any pieces with the bowls off so I'm keeping them all boxed up until then. I've read it's better to reuse the original components if they're in good shape instead of use the remanufactured ones so I'm just going to change the o-rings and just use the one new main jet since I'm missing one. Anyone know if mixing old and new jets would pose any issue?

Here's some of the sediment that was leftover after cleaning.

I did have one mishap. When I was taking out the bowl drains I had one snap off, I ordered a replacement drain screw, hopefully I can get the remainder of the old one out of the bowl. I have it soaking in PB Blast now:-\

Once I get the new hardware and put these back together my next move is to try and get this to run before I break it down. I'm going to change the oil and filter, new spark plugs and boots, hook up some new clutch cables and a battery throw the carbs and airbox back on and hopefully I'll have a runner.

calj737 · « **Reply #2 on:** May 04, 2014, 06:50:32 pm »

You can mix and match as long as they are the same specs. If you run short of carb parts, check with Harisuluv; he's got everything and anything you need.

onetruepunk87 · « **Reply #3 on:** May 05, 2014, 09:05:52 am »

Thanks for the info!

CoolerKing · « **Reply #4 on:** May 06, 2014, 03:40:49 pm »

Mcwilliams570 · « **Reply #5 on:** May 06, 2014, 05:51:39 pm »

If you need any 500 parts hit me up I have a 72 cb500 parts bike sitting in the garage. I saw this one on CL I am glad someone picked it up. Need any help help let know not far away from you.

Matt

onetruepunk87 · « **Reply #6 on:** May 06, 2014, 06:29:46 pm »

Quote from: Mcwilliams570 on May 06, 2014, 05:51:39 pm

If you need any 500 parts hit me up I have a 72 cb500 parts bike sitting in the garage. I saw this one on CL I am glad someone picked it up. Need any help help let know not far away from you.

Matt

Thanks, I'll definitely take you up on parts once I'm a little further along. I'm waiting on some general maintenance stuff now, I'm hoping it's here by the weekend so I can see if this thing fires up. Keep the popcorn on.

onetruepunk87 · « **Reply #7 on:** May 10, 2014, 07:23:32 pm »

So I managed to get the broken float bowl drain screw out, that was a huge pain. But it's out and replaced with a new one thanks to 4into1.com.

After all of that I replaced all of the old o-rings and was set to fully reassemble the carbs until I got to the float bowl gasket.

This thing is some kind of a sick joke. How the hell are you supposed to get this thing on, let alone stay in, while you attach the bowl? A quick search and I saw some people saying grease or a dab of superglue. I tried some grease and it still slipped out. I'll have to look and see if I have any superglue tomorrow but any other suggestions, I'm all ears.

On a positive note I found someone (relatively) local selling CB500 wheels on craigslist and I grabbed them and scrubbed them real good. The ones currently on the bike are rusted to hell. These ones were a little dirty but cleaned up really nice and were a good price.

riverfever · « **Reply #8 on:** May 10, 2014, 07:52:29 pm »

I used white lithium grease when installing those o-rings. I put some of it mostly on the corners of the bowl and then pressed the o-ring in and worked the grease on top of it. Worked very nicely.

onetruepunk87 · « **Reply #9 on:** May 12, 2014, 06:07:01 pm »

Carbs are back together with new stainless hardware. I Just need some fuel line and to get them back on the bike now.

onetruepunk87 · « **Reply #10 on:** May 18, 2014, 09:13:21 pm »

Not too much to report on, I didn't get as much time as I'd have liked to work on the bike this weekend. I did get the carbs back on the bike but it's not running yet. When I got the bike the start button on the right control was gone so I got a used control off of eBay and ran it through the bars and set it up, only problem is it doesn't seem to be working. I guess I'll have to going through all the wiring and see if the previous owner hacked it up. So with no starter button I tried jumping it by using a screwdriver across the solenoid. The engine turns over, which is a plus, but as of now I'm getting no spark. A quick look with a test light shows no power to the coils but i"m getting it at the points, dimly though. Again, I'm going to go through and check the wiring and bullet connectors. I checked the bikes fuse, which it only has one, and it's good. I've got new plugs and ngk caps coming and a few other things from Partzilla coming, hopefully tomorrow, that I ordered over 2 weeks ago. I thought Bikebandit was bad with their turnaround, I don't think I've ever waited this long for parts.

Carbs back on.

Found a wiring Diagram

What does this knob on the starter switch do?

Am I missing something here? There's a green ground female spade connector not hooked to anything behind the empty spot here.

onetruepunk87 · « **Reply #11 on:** May 24, 2014, 06:15:32 pm »

I got my rightside handlebar switch sorted out, cleaned some wiring, swapped in new spark plugs and boots, gave it some gas, plus a few shots of starter fluid and it came to life.

<a href="https://www.youtube.com/v/iaDN9-YT0SY" target="_blank" rel="noopener noreferrer" class="bbc_link bbc_flash_disabled new_win">https://www.youtube.com/v/iaDN9-YT0SY</a>

Still curious what this is supposed to connect to, any thoughts?

SOHC4 Cafe Racer Fan · « **Reply #12 on:** May 24, 2014, 06:19:01 pm »

Sounds pretty good for a first start!!

onetruepunk87 · « **Reply #13 on:** May 24, 2014, 06:36:35 pm »

Quote from: CB750 Cafe Racer Fan on May 24, 2014, 06:19:01 pm

Sounds pretty good for a first start!!

Thanks! Technically, I guess, this would be second start. But it only ran for about 30 seconds before this. One of the carbs is leaking out of the overflow tubes so I have to adjust the float but I'm psyched that it runs. It had a couple owners along the way that never even saw it running so it makes me really happy I got to bring it back to life.

calj737 · « **Reply #14 on:** May 24, 2014, 06:57:20 pm »

If your question is about the green wire on back of the electric panel, it's an available connector for Euro models running lights I think. Disregard it.

onetruepunk87 · « **Reply #15 on:** May 24, 2014, 07:58:23 pm »

Quote from: calj737 on May 24, 2014, 06:57:20 pm

If your question is about the green wire on back of the electric panel, it's an available connector for Euro models running lights I think. Disregard it.

Thanks for the info, I was scratching my head on that one.

I also found out what that little screw/knob on the right control is, it's so you can lock the throttle at different rpm's so you don't have to hold it open to work on things like points.

onetruepunk87 · « **Reply #16 on:** May 25, 2014, 12:27:31 pm »

Damn, found the source of the carb leak. I guess I'll try my luck at soldering this but if anyone has an extra, right-drain, float bowl laying around I'm interested.

onetruepunk87 · « **Reply #17 on:** June 05, 2014, 09:51:56 am »

Haven't posted in a while, not a whole lot of updates. I soldered the overflow tube on my carb and it's 99 percent better. It was pissing out now it has the slightest leak that I'm going to go back and fix. The soldering gun's tip wasn't working right so I'm going to grab a new one and finish the job.

I've been picking up a lot of parts for the bike thanks to the good people of this forum and some eBay stuff too. I decided I'm going to attempt a dual front disk setup so I got a whole "new" front end off of a 550. I got some chrome bits too because a lot of mine is rusted beyond salvage. I also got a steal of a deal on one of those Vietnam seats off eBay, $60 shipped from someone who had bought the wrong one. I wasn't even looking for a seat when I found it, just dumb luck.

I've also got a much nicer tank and shocks coming from a couple other members on here. I'm in the market now for a second brake caliper and mount if anyone has one. Could also use a nice front fender at some point but that's not urgent at all.

I hope to start dissembling the bike soon to get it ready for new paint. I also want to clean the engine up real good, replace some gaskets and give it paint and new bolts. Here's some pics of the new stuff I've got.

onetruepunk87 · « **Reply #18 on:** June 07, 2014, 03:56:13 pm »

Did some cleaning and polishing today. I took advantage of the motor still being on wheels to get some of the bigger crud off of it. Should make cleaning a little easier once I pull it off the bike.

I also polished up the lowers on my new forks, which came out really good. I finished both but here's a before and after comparison shot. I'm gonna try and get some more done tomorrow. Weekends are the only time I can get anything done so I try to get as much in as I can.

onetruepunk87 · « **Reply #19 on:** June 09, 2014, 09:00:06 pm »

I messed with some wiring yesterday and made sure everything was working, then tagged each connection with tape and started taking out the wiring harness and all of the other electrical connections. After that I started to strip down pretty much everything else. Not totally finished but close to it.

I was messing around tonight a little after work at getting the left side crank case cover off. I tried a little yesterday but the screws were pretty seized up. I hit everything with PB blaster yesterday and some more today and then hit everything with an impact driver to get them undone.

I was inspecting everything under there and thinking about how to go about cleaning it when I saw the clutch lifter rod and remembered reading a few threads saying that it was a weak point and prone to break from a loose chain. Well, unfortunately mine was broken as well.

I looked it up and of course, like everything else, it's discontinued. After a little more reading though, I found out it crosses a few different bike models and got one on eBay off of a cb500t to replace it.

Question, though, how do I go about getting the other half of the rod out? Is there a way to push it out from the other side?

calj737 · « **Reply #20 on:** June 10, 2014, 03:26:32 am »

Yes, the other end will be poking through under the right side cover. You'll have to remove the clutch basket to get to it. Also, look for the small steel ball from your left side, they're often stuck in the gunk accumulated under there.

Oddjob · « **Reply #21 on:** June 10, 2014, 08:24:27 am »

The answer to what the screw underneath the r/h switchgear is that it's part of what Honda was trying to call a cruise control, you wound the knob inward and a sleeper ramp located inside the switchgear was pushed up against part of the throttle pipe, this caused the throttle to stay open at whatever speed you set the cruise control at, it was possible to shut the throttle in an emergency as it made the throttle heavy but useable. Most of the sleeper ramps were lost when owners were changing throttle cable and not knowing they were there never noticed when they fell out. Finding a sleeper ramp these days is next to impossible, I do have 1 NOS one which I was considering getting copied by an engineering firm as basically it's just a strip of thin metal in a specific shape, nothing hard to copy about it just making sure the shape is right and the metal can withstand the crushing effect.

Hope that helps.

Check the push rod seal as when they break it can elongate the hole the rod runs through and cause a leakage, also remove the rear wheel and check the drum lining as they tend to crack a lot on the 500.

Oddjob · « **Reply #22 on:** June 10, 2014, 08:29:29 am »

Oh and the spare spade connector is actually meant to mount to the indicator relay, yours has been replaced by a non standard one which I'm betting only has 2 connectors, the OE one has 3 including one for that spare green earth spade connector. You can see on the pic just below the starter solenoid a piece of metal sticking off the harness sub-frame, a circular rubber mount used to sit there and the OE indicator relay used to sit in that mount.

onetruepunk87 · « **Reply #23 on:** June 10, 2014, 09:46:48 am »

Thanks for the info guys!

Calj, I'll check and see if the steel ball is stuck inside the cover, I didn't see anything fall out when I took it off so hopefully it's stuck in all the grease there. If it's not there I can just find a 5/16 ball bearing right? There's nothing special that it has to be a Honda part is there?

Oddjob, thanks for the cruise control info. It seems the extra spade connector was for you European blokes only. That flasher relay was busted so I grabbed an electronic unit at the store the other day to replace it, I'll try to get it to fit in it's intended spot when I rebuild.

calj737 · « **Reply #24 on:** June 10, 2014, 10:42:00 am »

Nothing brand-specific special about it. Just gotta have it. It's probably stuck in the muck like all the others over time.

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Author Topic: 1972 CB500K - Resto-Mod (Read 31141 times)