New Project!

"Urambo Tauro" (urambotauro) 09/12/2016 at 12:00 • Filed to: cl100, honda, motorcycle, project, wrenching, 1973, blog

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Well Oppo, I’ve got a new project to play around with: a “ran when parked” 1973 Honda CL100.

Here’s the deal: I told my father that I’d get his bike running again for him, provided that he dig it out of his garage. (A significant undertaking for him, but how could he resist?) I’m not gonna lie; this is kind of a big undertaking for me, too. I consider myself pretty handy with a wrench, but I don’t know anything about bikes. I’m not even a rider myself.

So just what exactly am I up against here? The bike has been stored in a garage for the past three decades. That’s right; it hasn’t been run in about thirty years . Now that it’s in my possession, I’ve taken a moment to rinse the dust and cobwebs off and start evaluating it.

Before even looking at it, I expected to have to rebuild the carburetor and put a new battery in. But there’s plenty more work to be done, some of which will have to be addressed before I even think about trying to start it...

The headlamp is busted, and the tail-lamp(s?) are missing

Fuel tank is rusted inside, and missing its cap

There is no connection between the fuel tank and the carburetor. Keys are currently missing (but might turn up soon, otherwise I’ll have to source new ones). Also, there’s supposed to be a panel covering the battery here, isn’t there?

Also on my list:

Bolts for the fuel tank, seat, and grab handle are missing.

Oil change, tune-up, check brakes, check tires, blah blah blah

I don’t know what exactly it’s supposed to look like, so I’m not sure if it’s missing anything else, or if there’s anything out-of-place. Are the front reflectors supposed to be pointing in different directions like this?

This will not be a full restoration. I will be focusing my efforts in two phases: getting it running, and getting it roadworthy. I found a !!!error: Indecipherable SUB-paragraph formatting!!! shop manual online, and have only begun to tear into it. I will share my preliminary findings in my next post.

bob and john > Urambo Tauro 09/12/2016 at 12:08

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oh god was the tank open???

here is your quick list

-battery
-check fuses/electrical
-entire fuel system, OFF (tank, fuel tap, fuel lines, carb, all of it)
- rebuild carb. fresh seals. new fuel lines. re build (or get a new one) fuel tap, fuel pump (if it has one)
-oil change.
0new spark plug(s)
-try to start it while drawing fuel out of a seperate container, NOT the fuel tank.
-it starts? great! take the tank to a specialist and have them clean it out. THEN re-intsall it. and get a gas cap FFS

now that it runs:

brakes, #1 job. these are older cable actuated brakes, not hydraulics. lube the cables and check the pads for life

once all of this is done, go over the major compotents front to back. forks, are they good? straight? not leaking anything?
head bearings. is it notchy? tough to turn?
swing arm: same thing, does ti travel through the suspension range evenly without any hic ups?

chain and sprockets: most likely need new ones...at least a chain.


then its making sure you have lights and away you go.

vicali > Urambo Tauro 09/12/2016 at 12:13

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Nice, my Dad fixes up ct90s as a retirement hobby.. some of them have started off pretty rough. The nice thing is Honda has a huge parts catalouge and most dealers can access it.

Open gas tank is a concern but probably not a show stopper- he had one that sat for 10 years with the sparkplug pulled and the cylinder hole open -parts bike ftw.

jimz > Urambo Tauro 09/12/2016 at 12:14

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yeah, that gas tank is going to be your biggest ball-ache. you def don’t want to even think about trying to run the engine on gas out of that tank. I’m not sure at this point how you’d go about fixing it. might have to have it stripped, split, blasted, and re-welded together.

does the engine turn over?

Urambo Tauro > bob and john 09/12/2016 at 12:14

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Thanks for that list!

The tank was indeed open. I have no idea how or why the cap didn’t stay with it. Good thing this bike’s been kept out of the elements, or else things would no doubt be much worse.

I assume there’s supposed to be a fuel filter somewhere. Maybe that’s what screws onto the bottom of the fuel valve? There’s a broken chunk of hardened hose on the valve assembly, and another on the carb, that I’m guessing used to be all one line. This might actually be gravity-fed, rather than pumped.

CalzoneGolem > Urambo Tauro 09/12/2016 at 12:15

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Personally I’d consider that tank a lost cause unless you’re particularly attached to keeping it as original as possible.

Urambo Tauro > jimz 09/12/2016 at 12:17

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I havent’s tried to turn it yet. I removed the plug (looked dirty) and stuck a scope in there. The piston appears to be at the top of its stroke, and is as dirty as the plug.

Urambo Tauro > CalzoneGolem 09/12/2016 at 12:19

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It’s not rusted through, so if there is a home method for cleaning it out (and maybe coating it somehow?), I want to try it.

Snuze: Needs another Swede > Urambo Tauro 09/12/2016 at 12:25

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Nice, bike looks surprisingly good for it’s age. I’m sure being inside helped a ton. I think Peter Black’s list is fairly comprehensive. Along with forks I’d also check the rear shocks, but those are after dealing with the major hurdles to getting it running.

As for the gas tank, before I ran out and dropped a lot of money on a new tank, I’d try a gas tank restoration kit. Eastwood offers one for $35 and there are others out there. My dad and I used one many many years ago on a little Honda 50 4wheeler he bought for me with success. It’s got 3 chemicals, a rust removing etcher, a metal rinse, and a tank sealer. You put the etcher in first to dislodge and dissolve rust, then rinse it with the metal rinse (non-water based so you don’t reintroduce rust) and then seal it to help prevent rust from reforming.

CalzoneGolem > Urambo Tauro 09/12/2016 at 12:27

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It’s not like you have a lack of things to do on this bike.

crowmolly > Urambo Tauro 09/12/2016 at 12:28

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http://www.eastwood.com/por-15-fuel-ta…

Decay buys too many beaters > Urambo Tauro 09/12/2016 at 12:29

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Yeah that tank looks like a lost cause, you can get some rust remover and ball bearings in there and shake it up to clean it, but I’d look for a cleaner replacement.

Urambo Tauro > Snuze: Needs another Swede 09/12/2016 at 12:34

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This one ? Looks interesting. I might give that a shot!

shop-teacher > Urambo Tauro 09/12/2016 at 12:35

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Cool old bike. Good luck with the project!

Urambo Tauro > crowmolly 09/12/2016 at 12:36

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Good idea! But that kit appears to be for full-size automotive applications. I might try the one Snuze suggested .

I hoon, therefore I am > Urambo Tauro 09/12/2016 at 12:36

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If you have an old-school battery charger, you can easily zap the rust via electrolysis . I did it on my XS650, and it worked well.

jimz > Urambo Tauro 09/12/2016 at 12:39

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what’s the oil look like? that is, if it (hopefully) has any.

citizenlambda > Urambo Tauro 09/12/2016 at 12:41

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Most carb fed bikes are gravity fed afaik. My 02 SV650 didn’t have a pump thats for sure.

Urambo Tauro > jimz 09/12/2016 at 12:42

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It has oil; it’s draining now. I’ll report my findings in the next post.

Urambo Tauro > I hoon, therefore I am 09/12/2016 at 12:43

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I like that idea! I’ve never tried that before, but it’s looks simple enough.

Snuze: Needs another Swede > Urambo Tauro 09/12/2016 at 13:04

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Yeah, I don’t remember if we used the Eastwood product specifically, it was many years ago (probably 20). But when I googled that was the first one that came up. I think you still need to buy a couple additional ingredients to make it all work (muratic acid and acetone) but both I think are relatively cheap and should be available locally.

I’d price a new tank and see what it costs and make the decision. But I think these bikes are getting popular now and so parts are going to start becoming rarer and more expensive, so it maybe worth spending the $50 to try the sealer method first.

Urambo Tauro > Snuze: Needs another Swede 09/12/2016 at 13:08

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To keep costs down, I think I’ll try the electrolysis method first. If the tank still looks salvageable after that, I can proceed with that kit. I really like the idea of coating the inside to prevent future rust.

450X_FTW > Urambo Tauro 09/12/2016 at 13:09

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pull the cylinder head cover off and pour a few quarts of oil down the top with the drain plug out. Hopefully grab some of that gunk sitting in the bottom.

bob and john > citizenlambda 09/12/2016 at 13:27

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yes it does. Vacumm pump (I JUST finished rebuilding one, I am well aware of them)

Snuze: Needs another Swede > Urambo Tauro 09/12/2016 at 13:29

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Yeah, I think that’s a good plan of action.

One thing I’ve noticed, I was looking at some of the kit comments, it seems like some people have problems with the coating flaking off and clogging their fuel filters. I’m not sure if they didn’t apply it properly or something, but that may be worth looking into before you head down that path.

Urambo Tauro > 450X_FTW 09/12/2016 at 13:30

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Which part is considered the “cylinder head cover” on something like this? I see two 1.75" caps at the front and rear of the top of the engine, and a larger oval-shaped cap on the left side.

Urambo Tauro > Snuze: Needs another Swede 09/12/2016 at 13:34

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I saw those comments too, and I think it’s either a failure to follow the direction religiously, or perhaps there were some ambient temperature changes during the process.

I think I might get a clear-view in-line fuel filter to keep an eye on things until I’m satisfied that the tank is clean enough for long-term use.

Snuze: Needs another Swede > Urambo Tauro 09/12/2016 at 13:39

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It sounds like you’re really on the right track with this. This sounds like its going to be a good project. Can’t wait to see how it turns out.

crowmolly > Urambo Tauro 09/12/2016 at 14:12

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Oh sweet! I thought Eastwood just made the big kit, the cycle kit should work well.

450X_FTW > Urambo Tauro 09/12/2016 at 14:20

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now that look closer, I’m not sure lol. From what I can see online, the cylinder head and cover all 1 piece. Whatever you disassemble, make sure you use plenty of PB blaster. See a lot of seized bolts in the future

Pickup_man > Urambo Tauro 09/12/2016 at 14:59

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Looks like a good project! Keep us updated.

I used muratic acid on a rusty 3 wheeler tank I had, worked well, other options listed here are good ones as well, do a little research, decide which is easiest and best for you. Definitely add a fuel filter, there are clear small brass cone filters out there, put one on and leave it on, even if you think the tank is clean.

Everything else is pretty well covered here, clean the fuel system, new plug, check for spark, fresh oil. Once it’s running tackle the other items such as the rusty fuel tank, brakes, and lighting. Do a good assessment and determine your priorities before ordering parts otherwise you could spend a lot of money on parts that do you no good in the end.

citizenlambda > bob and john 09/12/2016 at 15:35

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I will bow to your superior knowledge as wrangler is SVs. I was under the impression the vacuum actuated a petcock or something but no actual pumping went on. I’ll have to dig out the shop manual now.. curse you :D

bob and john > citizenlambda 09/12/2016 at 15:55

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There is a vacuum operated fuel tapon the tank. Then the line goes to the throttle side of the bike where there is a vacuum fuel pump. From there it goes betqeen the carbs and splits to them.

Birddog > Urambo Tauro 09/12/2016 at 22:45

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Vintage Honda on FB.

Get it cleaned up and running first. The best Carb cleaner you can buy is Pine Sol. No joke. Buy the biggest jug and soak it.

Urambo Tauro > Birddog 09/12/2016 at 23:23

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(Sorry, I don’t FB.)

Pine Sol? I’m gonna have to try that. Just the regular formula, no diluting?

Birddog > Urambo Tauro 09/12/2016 at 23:59

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I tried that. Any 3 wheeled contacts i can get are pretty valuable though. I can request parts if needed.

Yes. Regular Pine Sol full strength. It’s reusable too. I’ve used it to save carbs so bad they should have been chucked.

Urambo Tauro > Birddog 09/13/2016 at 00:08

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Thanks! Huh. I’ve never used Pine Sol for anything but mopping. When used full-strength, does it need to be rinsed off or anything?

Birddog > Urambo Tauro 09/13/2016 at 00:34

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A quick rinse in water and blow it off with compressed air. Or rinse and air dry and hit it with some WD40 or similar.

Monkey B > Urambo Tauro 09/14/2016 at 10:14

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Change the oil and make sure the piston isn’t seized. If the tank wasn’t so beat up I’d say clean and coat the inside...but you can probably replace it fairly cheaply with a nicer one. Never heard of the Pine Sol trick but it makes sense as it’s probably easier on the gaskets and seals than a solvent would be and a good degreaser, I’ll have to remember that. Once the carb is done and you know it cranks it’s all pretty easy from there. New brakes, tires, cables and chain oiled/adjusted and there’s not much else.

If the carb needs rebuilt it’s be the only thing you may need to have done by a pro. I’ve always found it’s best to have them done by those who are good at them...but I have fat clumsy fingers and low patience for little bits.

gmporschenut also a fan of hondas > Urambo Tauro 09/16/2016 at 20:18

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Cool