The Old Darling - '72 CB350K3

[jam3sk]

I recently picked up a CB350K3, titled as a '72 (as I understand they were titled as the year they were sold, not the year they were built.) The old darling is in need of some TLC, for sure... but I'm using her to learn about bikes, so I figure, what better way to learn about ALL aspects of motorcycles than to buy a motorcycle that needs work on ALL aspects?! She does turn over, though, and sounds very nice while doing so.

She's a beautiful machine with lots of potential:

Last week, I posted a much more detailed, yet ridiculous "introduction" with way too many questions all at once, not knowing much of what I was talking about, getting ahead of myself all over the place:

http://www.dotheton.com/forum/index.php?topic=19717.0

I would REALLY have loved to have spent the whole weekend getting things underway, but some idiot scheduled Halloween for the same weekend, and my daughters (11 and 7 yrs) seemed to have had certain expectations, for some reason.

In any case, I didn't get far beyond a partial overall grease-adhered-dirt removal, and de-jamming the seat latch to see what was going on underneath. Like an idiot, I neglected to take pictures of this particular item, but there was a nice little wasp's nest i discovered in the battery compartment once I de-jammed the seat latch!

Here's the de-gunked, de-nested, still rusty under seat pic:

There's actually more rust in there than on most of the rest of the frame, or really anything that can be seen from the outside. The inside of the tank is another story... we'll get to that later.

I have some initial items on order:

- battery
- battery tender
- tires (current won't even hold air)
- crap... i forgot tubes
- brake shoes
- spark plugs
- fork seals
- clubman bars

The final item is not currently a functional necessity... more of a necessity in the kick-ass department.

Anyway, my first order of business (aside from generally cleaning and de-greasing whatever I can reach) is to pull the tank and get it clean inside, using the various methods I've been reading about here and elsewhere online for weeks. I'm not totally sure, though, how to handle it once it's clean... do I coat it immediately with red kote or kreem, or can I just coat the inside with WD-40 temporarily? I don't want to go too crazy on the tank before I do some basic engine testing, for which I'll need a tank that can at least hold clean gas.

After that, with a new battery, plugs and an oil change, I'm hoping to be able to see if I can get her started. That'll direct me toward where to go from there... compression testing, etc.

What else should I be doing to make sure all the basic internal systems are clean enough so that I won't ruin the engine once things inside it start moving really fast? This is, of course, short of tearing it down completely, cleaning it ultrasonically and replacing all the gaskets (which I've been advised not to do until I've confirmed that she'll start up and run decently with what she's got.)

 

[KYL3]

Sounds like a good plan. I read your intro, and my advice would just be to take it slow and enjoy it. I rushed into mine, thinking I'd have it done fast and be riding before winter hits, but that led to mistakes, wasting $, and looking like crap hahaha. Now I'm just doing a little here and there with buddies, slowly cleaning up stuff, and just enjoying it.

I can't help ya on any of your questions, as mine ran when I got it, but I'm sure everyone here can help !

Good luck with the build bud, I like the old feeling to the photos !

 

[Bobdot]

I'd say the best thing you can do (especially while you're waiting on parts) is to take the carbs off, tear them down, soak all the metal bits in carb cleaner, and blow it all out with more carb cleaner and compressed air. One thing to look out for is keeping the cleaner off of anything rubber as it will ruin it. Take out all of the jets and make sure all holes are clean as a whistle. While you ordering parts, look into two good carb rebuild kits, as the seals will most likely be bad from sitting.

These are awesome bikes and very reliable once they are tuned up right. Main things that I've found in my journey with a CB350 is wiring and carbs. Start with the carbs and move onto checking electrics when you get your battery. Buy as many 15amp fuses as you can find and a good multimeter. If the headlight comes on when you turn the key, you're halfway there!

Keep up posted on your progress, there's lots of really knowledgable dudes on here.

Here's a few sites to have a look-see at:

http://www.siriusconinc.com/ - Great place for all sorts of carb parts and kits, the guy knows his stuff. Avoid ebay for carb kits unless someone recomends something specific.

http://cb350.blogspot.com/2007/05/carb-rebuild.html - Really good blog on rebuilding 350 carbs, helped me out in the beginning

http://www.oldmanhonda.com/MC/DataTable.html - Data tables with all sorts of info, tune accordingly

Have fun, getting these thing running is a ride in itself. I have a K4, so feel free to ask away.

bob.

 

[IndieSol]

Cool bike. Looking forward to more updates.

 

[Ethanol]

Gonna be a cool build. Hope I didn't bust your balls to hard in that first post. Let us know how we can help!

 

[jmal18]

I agree with KYL3...I wasted most of the season tinkering with little know how instead of taking the time to do it right the first time...make sure you take care of your battery bc its half the battle! Once you get it running right you WON"T regret taking the time to do it...everybody loves seeing old Hondas rip!!

 

[Bobdot]

Oh, and dont forget new rim strips when you order those tubes.

 

[jam3sk]

Alright... just a little more exterior cleaning and de-gunking today before going in to work. I was happy to find that the grease/dirt combo on the forks and rims seemed to be functioning as a pretty good protectant while in storage. It's a bitch to scrub off, but easier than rust removal!!! I hope to finish the initial clean this weekend, then get to work on:

- an oil change
- beginning my tank de-rust project
- using my buddy's ultrasonic cleaner to do my carbs

So... do I need a "carb rebuild kit?" Or do I just need the gaskets & seals?

Also, what about gear oil? Shifting's currently a bit sketchy. I'm sure brake & shift cables are going to need some work or replacement, but should I be at least cleaning and oiling things in the mean time?

Finally, a few new pics of the old girl, just as non functional, but a whole lot prettier:

 

[Bobdot]

So... do I need a "carb rebuild kit?" Or do I just need the gaskets & seals?

You'll know the answer to that the moment you crack those puppies open, I'd go for a good full kit, it will come in handy I promise you.

As for gear oil, original spec is 10w-40, 2 liters (2.1 US Quarts) I use regular car oil for high mileage engines but I know the crowd favorite is Honda GN4:

Found at numerous places online and at you local Honda dealer.

This is the only oil that gets put in the engine. One and done. That whats so great about these vintage bikes, the "simplicity". I imagine that if there is any oil in your bike its mighty craptastic, make sure you drain her good and pay attention to what comes out. Can often tell a good story as to whats going on on the inside.

She is cleaning up mighty nicely, that color is awesome. Keep it up!

bob.

 

[jam3sk]

Alright... I've done a little more, though not as much as I thought I would have at this point. These things take TIME!!! My immediate goal is to get 'er started, and to that end, I'm concentrating on fuel, air and spark... and an oil change!

So far, I've purchased the following online... some critical right off the bat, some once I started digging in, and some for fun. I've gotten about 50% of it in:

Dime City:
- clubman bars
- fuel line
- inline (universal) fuel filters
- rear brake shoes

Bike Bandit:
- front brake shoes
- battery
- battery tender
- clutch pedal rubber
- spark plugs
- tires, tubes & rim strips
- fork seals
- bits for petcock rebuild

S.C.I.
- Keyster PREMIUM carb rebuild kit

I spent more of my Saturday than I wanted to running around town for additional items:
- a gallon of that GN4 oil from the local Honda dealer
- a gallon (dip can) of carb cleaner
- wire brush drill attachments for some frame/battery cage de-rusting
- "rust cutting resin abrasive media" from Harbor Freight Tools for the inside of the tank

After scrubbing some more gunk off the exterior, I got to work pulling the carbs which, let me tell you, was not as easy as I expected. I am reminded how, the first time you do anything, it takes 3 times longer, just because you don't know what requires muscle or leverage, what you have to be super careful about, and what little screw or cable needs to be loosened before you can get anywhere. Also, the Clymer manual is great, but only with a supplement. Mine was having the web available on my iPhone throughout. I didn't expect to have to pull the tank off to get to everything, but THAT was easier than I expected since it's just held in by that rubber piece where the seat meets the tank. That seems like something that may need replacing, though, because a thick, slightly cracked 40yr old piece of rubber that is all that's keeping your tank from falling off sounds like a bad idea. Also, there is some serious crap inside my tank. SHEETS of rust, or rusty liner, or rusty, rusted rust soaked in gas so old, it smells like paint thinner. Here's crossing my fingers that the upcoming cleaning doesn't uncover any leaks!!! The old, brittle equalizing fuel line between the two chambers of the tank fell apart when I had to flex it to get the tank off. Thanks to this forum, I was prepared to avoid spilling gas everywhere, but draining the tank was still an unpleasant experience, to say the least. To catch the remaining drip of old fuel/rust, I just hung some zip-lock bags off the little nibs until I get the tank cleaned properly and new fuel line on there.

Anyhoo:

I pulled the side covers, air filters and tank, then tried to figure out how to loosen/release the throttle cables:

Then I found a nice little wasp nest right by where the cables connect to the carbs:

The job went a little later than I expected, but I adapted:

Like everything else, the carbs were gunked with rusty hardware on the outside, though not terrible inside:

Disassembly was a bitch, and I had real trouble loosening the jet holders and kinda f-ed one up (http://www.dotheton.com/forum/index.php?topic=20003.0,) but there are new ones in my rebuild kit, which is on order. Unfortunately, it may be a while before they get here from the great, white north.

After a dip overnight on each housing and float bowl, things started looking up:

What I'm really looking for now, though, is a good Aluminum cleaner. Though the housings and float bowls came out varnish-free, they were dark and oily looking, even after a hot water rinse with a good toothbrush scrubbing. I happened to have some Brasso, and tried that on the outsides of the housings and float bowls, and it DOES result in a nice, black cloth and LESS black aluminum that feels somewhat protected, but there are so many nooks and crannies on the outside of the housings, and even the float bowls require some serious elbow grease. Is that just the way it is, or is there an easier way? I spent three hours on one housing and didn't get much past an initial once over and having to q-tip out a bunch of Brasso from the nooks and crannies. Someone at work suggested some kind of acid that you spray on, then rinse off right away. That sounds a little scary, not wanting to corrode any of the delicately proportioned inner chambers. Any ideas? I see posts on the "full monty" with buffing wheels and polishing compound, but I'm not there with this project yet... and I think the carbs are too small and intricate for big wheels and such, anyway. I just want to get things cleaned up.

Tank cleaning and petcock rebuild are next, while I wait for my carb rebuild kits!

 

[jam3sk]

She's coming along!!! I have one carb cleaned up and rebuilt (used NevrDull on the dark, post dip Al to acceptable results,) and the other in queue for the same treatment. I am a LITTLE worried about one of the slide diaphragms... there's the beginning of the BEGINNING of a slit, but I'll worry about that later. It's an easy enough fix, just expensive.) Incidentally, I picked up a couple of needle clip plates for cheap, listed for an SL350, where I could only find the full needle jet kit for the CB, but they ended up being the same size. In all, I replaced all the jets and holders, caps & such, float needle and seat, gaskets & o-rings. I had to do a little soldering on one of the floats, but that was just for a couple of tiny holes.

I also got my new battery filled and charged, and used some conditioner on the rubber tank mount pieces. I've got my tank full of white vinegar after a somewhat nasty process of shaking up those little resin abrasive media with soapy water and dumping half a dozen times (THAT was a workout.) I'm going to start round 2 with fresh vinegar tonight, but I'm afraid I might have to take more extreme measures. It's been sitting for a week, now, and I don't think it's completely rust free. When I DO get there, though, it sounds like people here like Red Kote over Kreme as a sealer?

Anyhoo, my plans for the petcock have changed... I've got it cleaned up, and have a gasket and o-ring kit, but the brass intake tubes/filters were broken off when I removed it, and they don't look replaceable to me. The brass outbound tubes are in tact, but were in the long ago disconnected fuel lines rather than firmly in the petcock. I couldn't tell if there was a way to re-seat those securely, so combined with the filters issue, I just opted for an OEM replacement (which is on order.)

Also on the immediate agenda is an oil change, spark plugs, new fuel lines & inline filters to protect my freshly rebuilt carbs, mount the tires, tubes and rim strips (just so she's easier to move around than when on rims resting on old, split rubber) and a new drive chain. I've also got a center stand coming from VonYinzer, in exchange for those old dusty saddle bags. I hope he does something cool with them.

After all this, I'll try to start the Old Darling up! That is an exciting and frightening, but either way highly anticipated day! There's plenty of work to be done after that just to get 'er ridable, but I look forward to bringing her back from the dead!

OH... AIR FILTERS! Stock ones with the metal base are expensive. Foam ones are cheaper, and I've heard good things... but can foam Uni-Filters be used without increasing the flow of fuel? Is there some other solution that is newer/cheaper/better that maintains the appropriate air flow for a stocker?

Finally, I think I'm starting to get some style inspiration (for when I finally get to that point) from a shop in Denmark. I wanted to find a solution to having a sporty, cafe look without a bump-stop seat, so I can still ride 2-up with my lady friend. If you haven't seen them already, check out what the WrenchMonkees are doing: http://wrenchmonkees.com/monkee15.html.

That's still a solo bike, it looks like... but it gives me ideas!

 

[jam3sk]

Progress has slowed with the holidays and, eh-hem, lack of availability of funds, and updating here has slowed down even more. That said, I am making at least a little progress, albeit too slow when compared to my desire for at least a running bike.

De-rusting the tank was a bit more of an adventure than I'd planned:
http://www.dotheton.com/forum/index.php?topic=20498.0

I decided to go ahead and sand blast the exterior before the Por-15 on the interior... there was a lot more exterior rust than you can see here. I only succeeded in getting the existing paint to shine really nicely, but the exterior rust only seemed to get worse, faster, once I got rid of it and tried to coat it with something:

Sand-blasting was a lot of fun, though sometimes painstaking with the small, low powered machine I was using:

I forgot to take a pic straight out of the machine, but I blew off the dust with compressed air and wrapped it in pallet wrap before bringing it home to spray clear rustoleum on it (until I can get it properly painted,) then hit the inside with the whole Por-15 prep and seal (which I haven't done yet):

I also blasted the badges, which were significantly scratched and marred. Now they've got nice edges for polishing and a rough inner surface for painting:

I'm glad I decided to do the tank exterior, though, because it forced me to remove the gas cap, hinge and lock. All the banging to get those pins out dislodged more rusty, flakey shit that I thought I had already rid myself of with everything I had ALREADY done. I'm glad I didn't go straight to the Por-15 and seal that crap in for life, or end up without a good seal.

What is the best thing to paint badges with? Is model paint a terrible idea? I was also thinking about just polishing all those nooks and crannies, and having naked badges. What are those things made of, anyway? They seem to have a fair amount of flex, but the previously exposed edges were not rusted or oxidized in any way.

 

[Reinhard]

The badges are pot metal. Any enamel should work

 

[bikeboy]

What is the best thing to paint badges with? Is model paint a terrible idea? I was also thinking about just polishing all those nooks and crannies, and having naked badges. What are those things made of, anyway? They seem to have a fair amount of flex, but the previously exposed edges were not rusted or oxidized in any way.

have a look at this One I prepared earlier

Might give you some ideas?

cheers
ian

 

[jam3sk]

Thanks for the link! It definitely gives me ideas.

 

[nftyper]

Excellent progress there. Im in the same place as you are with my '70 CB350, which its in the same condition as yours. im doing the tank right now but its just for the experience since ill be putting in a new one. I just have a question on the air box. How did you get it out? Is it from that pin bolt that holds the air box cover? cause mines just keeps spinning and it doesnt come off. Or is it the bolt thats on the frame? Or both?

I figured out the airbox removal. Im also working on the carbs right now. Did you ever get her started with the rebuilt carbs?

 

[jam3sk]

Alright... it has been quite a while. A lot has gone down. Stops and starts, things expected to be small that were significant projects, job change, failures, successes and times I thought I was going to pull my hair out. She's still not "done," but I've learned that will likely never be the case. I got my 350 up and running last summer (though somewhat roughly), and rode through December. After that, it was either BITTER cold in the mid-west, or I had my daughters to drive to and from school for a couple of months. The spring brought a few weeks worth of new challenges, but she lives!

I'm sure I'm missing a LOT here, but this is the basic rundown of what was addressed overall:

- Tons and TONS of cleanup, degreasing, scrubbing, sanding, soaking, fighting old bolts and stuck bearings... too much to list
- Carbs cleaned, rebuilt with new jets, gaskets and o-rings (small diaphragm hole - guerrilla glued)
- Tank cleaned, blasted, lined with POR-15, painted, imperfections sanded & polished
- New petcock, fuel lines and filters
- New clutch, tach, speedo, throttle and brake cables, etc
- Old wiring and controls run through new clubmans with new grips and throttle tube, plus bar end mirrors
- New headlight, taillight and signals
- Headlight bucket, fork sleeves and ears blasted, painted, sanded and polished
- Fork tubes cleaned & polished, lowers brushed and forks rebuilt with new seals, springs cleaned and oiled
- New drive chain
- Wheels cleaned and checked for true, new bearings
- New tires, tubes and rim strips
- New brake pads
- Battery box sanded and painted
- Center stand (from VonYinzer) de-gunked, sanded, painted and mounted
- New battery and plugs
- Dented rear fender chopped and straightened (with new taillight mounted)
- Air filters cleaned, plastic airbox covers removed and black metal airbox covers cleaned up pretty-like
- Oil changed (and came out VERY clean)
- Many nuts and bolts replaced with stainless
- Lots of new/replacement bits and pieces throughout
- Everything with fuel delivery, shifting and braking adjusted to spec (which is definitely a learning/do-and-redo-and-redo, etc process)

After big, bad afterfire issues this spring:
- Better condition, same spec carbs from a swap-meet cleaned and rebuilt with existing new jets, gaskets and o-rings
- New header crush gaskets (didn't realize they were there the first time!)
- New points, and finally got over being afraid of setting gap and timing.

She's running very nicely, my friends. I am definitely running rich, but I've dealt with the power loss for a week just to get a little riding time in while I catch up on all the other stuff I've been putting off. That is to say, the stuff my lovely wife expects me to do as a responsible, grown-ass man.

If you've stuck with my so far, here's your reward:

At Vintage Bike Night STL (always lots of attention):

Fender... mock-up:

Cutting:

After grind, file, sand and polish with new taillight mounted:

Various stages throughout the process:

(Yes, I know the filters are reversed. That has been corrected):

Here are my early sketches of what I wanted to accomplish:

I still have a good bit of dialing in to do (though service and adjustments seem to be a never ending part of the game). I also have more cosmetic changes to make, and am always finding a new piece of rubber to replace, but it's a lot of fun! Each item is a new learning experience.

I plan to shave the seat down by about 1/3 with new foam but the old, seasoned cover. I'm also going to mount my plate on the rear axel, get the new signals back on (front, fab'ing a mount for the back) and figure out a nicer way to cover the old taillight holes than the current electrical tape solution. I was also thinking of wrapping the headers in black and painting the silencers matte black. Not sure on that yet.

Either way, I think I'll do a proper photo shoot (with a decent camera in a cool spot... maybe that red-orange garage) as soon as the seat and plate mount are done. I'll definitely be posting more frequently from here on out.

 

[jam3sk]

Sooooo... as if posting my progress and successes has invited trouble, yesterday (on the way to work) I encountered an odd condition in which my bike would rev as I was coming to a stop, with the clutch in. I stopped on a decline, so I didn't think much of the fact that the bike wanted to roll forward. I also didn't think too much about the fact that I had to give her a little extra gas when stopped, since I'm constantly tweaking, working on trying to get the right mix/idle etc. I figured it was some sort of carb or fuel issue, though I had been through all that when troubleshooting the afterfire. That said, I never assume something is done for good after I've done it, since she's overall a bit needy in her old age.

Shifting starts getting a little finicky, but I don't read too much into that, since there is not generally a whole lot of finesse to shifting on these old girls. Jam it up, jam it down... used to scare me at the beginning, but I got over it. So after a bit longer, it became clear that the clutch was not fully disengaging. I decided to get to the parking garage at work (not too far) so I could adjust the clutch cable and check things out without being on the side of the road, so naturally I hit every red light, and the condition just kept worsening. I struggled to keep from stalling, sometimes killing the engine just to get back into neutral (which seemed to work better with the engine stopped). It was not an overall pleasant ride, to say the least.

I went through the clutch cable adjustment procedure: slack the cable at the lever, slack at the cover/housing, loosen the adjuster locknut and back the adjuster out until you feel resistance, then 1/4 turn clockwise. Tighten adjuster locknut, then adjust at the cover/housing until there is about 20mm free play at the lever (measured at the tip/end of the lever). I knew I hadn't adjusted that since I first installed it, and that initial cable stretch was likely the issue.

Unfortunately, I was wrong. Things were fine at first, but about halfway home everything got worse than ever. I basically rolled through every stop I could, and controlled my speed by squeezing the hell out of the clutch lever and jamming into gears. Sticking to side streets, I didn't have to change gears too much.

So I got up early this morning and lubed the cable and checked for that bearing inside the sprocket cover that everyone is always losing (which was there), but I noticed/was reminded that I was missing both bolts (top and bottom) on the left side of the sprocket cover. The PO somehow lost (or stripped and never replaced) the M6 x 55mm bolt at the top. The one at the bottom had been one of my more challenging removals early on in the build (had to dremel slice a flathead notch in it to get it out, since those original Honda bolts are just a little harder than cold butter). I thought I had put it back until I could find a replacement. Guess not. At least the bolts on the right side of the cover were torqued down.

I readjusted the freshly lubed cable, but when I pulled on the clutch lever I could clearly see that the cover itself pushed out. No wonder I was having trouble! Honestly, I don't know how I rode through late summer, fall and most of winter. Good old bikes and their tolerances, I guess. Granted, clutch was spongey, but I figured that was due to initial cable stretch and general old bike wear.

So I stopped by the local mom and pop hardware store close to my house that has a reasonable selection of metric and metric, stainless hardware, artfully shifting around the poorly assembled clutch. Even with their selection, I had to go with a zinc plated 60mm bolt and some washers to account for the gap. Regardless, the difference is AMAZING, as you could expect. I installed the bolts (which I'll replace with metric stainless socket head cap screws at the proper lengths, along with all the others on that side) and readjusted the clutch cable, and BAM! Problems I didn't even recognize as having to do with that are gone! Shifting and controls, throttle and low end acceleration are so freaking snappy!!!

Every time I fix something I didn't know was exactly "broken," it illustrates how nicely this bike <i>could</i> run. Unfortunately, I have no frame of reference, since this is my first. The way I generally look at these things is, well, it's another thing to learn, and more experience under my belt. Despite all that, there are definitely moments when I think, "well, it's another thing to learn about... another GD, MF thing to learn about, fer chrissake." Of course, that's forgotten as soon as I'm on the other side of the issue and riding again.