Backfire Moto

Yesterday I took the bike to my first Backfire Moto event, a local vintage motorcycle meet-up that happens on the 3rd Wednesday of the month. Last night was Backfire Moto #37. The bike ran great, no problems and good power. Here are a few pics. Only the red Honda SL350 is mine. The other pics are a few of the other bikes that were there (there was probably around 100 bikes there).

What Next?

OK, in my last post I mentioned that I was going to try and top up my battery. After an overnight charge on a 1 amp float charger, it only got up to about 11.36V and was falling (with nothing attached to it). The battery definitely seems toast. I took it to the auto parts store and asked them to load test it. They said that they don't load test motorcycle batteries. But they did have some other sort of tester, which they attached to my battery. It said that I have 0 cold cranking amps. The battery is only 6 months old, but I guess I have to replace it anyway.

Another potential problem, my new voltage regulator/rectifier is allowing my DC voltage to climb to over 16V at higher RPMs. I am hopeful that this has something to do with the bad battery. But I'll have to wait and see.

Got the new battery, filled it with acid, and gave it an initial charge. I put it on the bike, and thought that everything would be good to go. But, it wasn't.

The good news is that the issue that I was observing with the regulator/rectifier unit was indeed caused by the bad battery. With a new battery in the circuit it now doesn't go above about 14V. The bad news is that it ran like crap again. It didn't want to idle and it had no acceleration power.

I pulled the spark plugs. The right plug looked fine. The left looked dark and wet. I pulled the cover off of the points housing. The right cylinder points were sparking, the left were not. I pulled the left plug wire off with the engine running. No change. Clearly the left cylinder is not firing at all. I started to suspect the coil. As far as I know, you can't buy a new replacement coil identical to the original. You either get to modify or buy an old coil. And they aren't cheap. But, before assuming the coil was bad, I wanted to check for wiring problems. I undid my charging system wiring mod (the one that bypasses the headlight switch). No change. I pulled the tank and checked the wires to the coil. I noticed that the connector for one of the wires wasn't fitting snugly. And as I unattached and reattached it a couple of times, one of the connectors crumbled. I created a new pigtail to bypass the bad connector. Boom, I get spark on the left.

Well, it was after dark and getting late so I haven't done a thorough test. But my one trip around the block went great, the best power from the bike yet. Of course I need a longer test, but I am encouraged to say the least. I will consider redoing the charging system wiring mod. And the clutch needs adjustment. But I am shooting for a trip to Backfire Moto tomorrow night.

Charging Sytem Upgrades

Given that my charging system appears to have problems now, as I fix it I might as well upgrade it a bit. Apparently these bikes have always had a charging system that was barely adequate. And that was in 1971, before bikers ran their headlights all day. And on a bike that didn't come with turn signals (which I have added). So, I decided to do these two mods:

headlight switch bypass mod: http://www.hondatwins.net/forum/viewtopic.php?f=53&t=6185
regulator/rectifier mod: http://www.hondatwins.net/forum/viewtopic.php?f=46&t=14530

The first of the 2, on my bike, will only help when the headlight is off. That should be pretty much never. But I can see turning it off to try and limp home if I have another charge issue.

The second mod allows me to replace the existing regulator and rectifier on my bike with a single combined rectifier/regulator unit. Here are the old bits:

The stock voltage regulator

The stock rectifier. I dissembled it to get the wires out, I intend to reuse the pigtail.

I replaced both of the units above with this new combined unit (front and rear view):

I modified the pigtail like so:

Here is the modified pigtail attached to the new unit:

And here it is attached to the bike (where the old rectifier was mounted):

Unfortunately I cannot yet report on how it works. It appears as though I may have killed my new battery by discharging it too many times. I am going to try and top it off and see if it works. But if not, I will have to get a new battery and then test this mod.

Still Tuning

OK, so I haven't posted in a while. What have I been doing? Lots of tuning, some repeating old work but trying to do it better. For example, twice I adjusted the point gaps and set the timing. But I ended up doing it a 3rd time when I decided to put in new points and a new condenser. Similarly, twice I have disassembled and cleaned the carbs. But I just did that for a 3rd time with new internal parts (i.e. jets, needle, gaskets, etc.).

The bike now seems to run a lot better, but only under certain conditions. First, it is harder to get it started. Once it starts it runs well and has more power ... for a while. Twice I have ridden it to work. It ran well, both time, for the initial part of the ride. But it was running rougher by the time I got there. Both times I was barely able to keep it running for the trip home. I concluded that it ran fine cold, and even warm, but hot was a problem.

That is until I discovered another problem. The charging system wasn't working correctly. I had attributed the change in how the bike ran to its change in temperature. But I now think that it was simply how long I rode. You see, I was putting the bike on a trickle charger at home. But when riding it, it eventually drained the battery to the point where it runs poorly. I am now putting this theory to the test.

Turn Signals Working

With the switch mounted and a new electronic, universal motorcycle flasher installed (the one I bought previously was mechanical and failed to work properly) I was ready to wire up the new signals. I mounted the front signals to the sides of the headlight can, as they are on Honda CBs. For the rears I made two brackets (one for each side) that I screwed to existing threaded inserts I found on the frame, and mounted the signals to these brackets. Note that I had some initial problems getting the signals to work due to insufficient grounding. The signals have case grounds, so I used ring terminals attached to the turn signal post mountings to ground all signals to a good ground (there was an available green wire under the seat and one in the headlamp can). Here is a short video of the working signals:

Turn Signal Switch Install

With my modified turn signal switch in hand, I set out to install it on the bike. The first thing to do was to remove the old horn-only switch. I unhooked the wires from within the headlight housing, disassembled the switch housing and tried to pull the wires out from inside the handlebars. They were in there fairly snug. Unfortunately I ended up tearing the wires off of the original horn switch, but I got them out. To facilitate installation of the new switch, I had attached a piece of string to the old wires before pulling them out of the bars. I now had a string running through the handlebars, along what would be the route of the new wires.

Well, that all sounds great. But there was a problem. The old hole, to get wires into the handlebars from the switch, was too small. The new switch has more wires and requires a larger hole. How was I going to drill out the hole without loosing the end of the string running through the bars?

Well, I decided to push the string just inside the bars and then drill the hole. I was hoping that I'd be able to fish it back out somehow. The string ended up slipping too far into the bars and I was unable to see or reach it after drilling. The solution I came up with was to use air to blow the string back towards the hole. I don't have an air compressor, so I used that canned air you use to clean out electronics. It worked great!

The switch housing had a pin in it which protruded towards the bars, presumably to make sure the housing is properly oriented on the bars. Since my bars lacked a receiving hole for this pin, I just cut it off and ground it down flat.

After much wresting and a bit of re-soldiering, after I tore a wire loose from the switch, I got the new switch wires run and the housing mounted. Unfortunately it is not perfect. I cannot get the housing to close all of the way. I don't have a good picture of it, but there is about a 1/8th inch gap between the upper and lower parts of the housing. The wires internally are keeping it from closing. I'm not sure what to do about it, perhaps I started from the wrong switch. But for now it is installed sort of. Fitting the new switch was by far the hardest part of adding turn signals to the bike.

Modding the Switch

As I mentioned in a previous post, the original, optional, turn signal switch for this bike is nearly impossible to find (unless you are willing to spend exorbitant amounts of money for it). Sources a reasonable replacement, from another vintage Honda, is a problem also because they all seem to have one of two issues:

1. They have a headlight hi-low switch on them. On the SL350 that function is already controlled from the other (right) handlebar switch.

2. They have the base of the clutch lever, and rear-view mirror mount, cast integral to the switch. On the SL350, there is a separate bracket for the clutch and mirror.

So, I bought a switch (aftermarket part, like the vintage Honda switches but not for a specific model) that had the clutch and mirror mounts, and decided to try and modify it to resemble the original. Here is a picture of the part before I started (the protrusion on top is where the clutch and mirror mount):

I began by cutting off the bulk of the mount with a sawsall:

Next I used a rotary grinder to further shape this area. And then I sanded the results of that.

 

Lastly I painted it, and then I was ready to go, or so I thought.

Turn Signals

Well, so I've been contemplating adding turn signals to the bike for some time now. I just think it would be safer. I mean, you can use hand signals and all, but not always when you want. The signal hand is also the clutch hand. Plus, I've been getting mixed messages about whether or not they are required by law in Washington. Some say that the bike is grandfathered in, due to its age (it didn't have signals when new, it doesn't require them now). Some say that the Washington turn signal laws don't apply to motorcycles. And a lot of web sites list Washington as a state that doesn't require them. But the RCW that applies to turn-signals seems to suggest otherwise:

http://apps.leg.wa.gov/rcw/default.aspx?cite=46.37.070

So anyway, Ive started the process of trying to retrofit the SL350 with turn signals. Apparently these were optional items when new, though I think few had them. The parts for the SL350 specifically, like the handlebar switch, are nearly impossible to find. But there are available substitutes from other vintage hondas. Here is a little video of some initial testing of some of the parts I've acquired.

Safety First

My new helmet has arrived.

Tire Changing

Holy crap, who new this was going to be so hard. I'm not sure if it was because the tires that were on there had gotten stiff with age, but they were impossible to get off. I ended up, after hours of wrestling, cutting off the back one with a saws-all and an angle grinder. And don't get me started about those bead lock devices in the rear tire. I forgot to take a picture of those, sorry.

Here are some pics of the process. As you will see, the first thing that I had to do was construct some devices to help hold the bike upright while I tried to lift one end. Coming up with a proper lifting scheme took some time. At one point I had the bike tied to the ceiling of the garage until a rope broke and it nearly fell over.

As there was no way to put anything wide and flat under the frame (the exhaust being the lowest part), I was left jacking the bike up by a single point at the bottom of the engine. This meant that I needed another way of keeping the bike upright. This contraption above is what I came up with. The pic below shows the bike on the jack, help upright with my rig, with the front wheel removed.

The wheels were rusty inside, underneath the tires. Before I put the new tires on I cleaned them up a bit with a sanding screen and wire brush. I then painted on some rust converter. I also added new rim strips (there was no rim strip in the rear). I modified the rear rim strip, adding extra holes for the two rim lock devices (not pictured). I considered omitting these devices since they were difficult to install and probably unnecessary for street riding. But I got them in eventually.

And here is the rig on the front with the back wheel removed. It was far more precarious this way since the front wheel can turn.

Here is the tube that came out of the back wheel. It had 8 patches on it! I guess Gary must be an expert at changing tires.

And here it is with the new tires on, finally.

Choke

So far, the posts I've made showing the bike running have been only with the choke on. The choke is simply a mechanical door that restricts airflow through the carburetor. I've had a running theory that the problem might be partially related to the fact that I have had the air cleaners off of the bike. The air cleaners on this bike are fairly restrictive, they are oil soaked foam elements. Today I reinstalled them and tested. It now idles fine with the choke off. So I guess there isn't a problem. Nice!

First Test Drive

OK, so it's only in 1st gear and only in the driveway. But hey, it's a start.

Oil Filter

Before I ran the bike any more, I wanted to make sure that the oil filter was clean. This motorcycle doesn't have a disposable paper filter like is typical on a car. Instead it has a centrifugal type inside the crankcase. I disassembled and cleaned it out. Here are a some cleaned-up pics.

Now, when I took the crankcase cover off, it had a gasket on it that immediately self-destructed. I looked through the manual that came with the bike, a repair manual that I purchased, and several online sources, none of which indicated that the bike originally had a gasket there. It looks as though an earlier bike, the CL350 had one, but this bike should have had an o-ring only. During reassembly I used a wet stone to improve the surface and put in a new o-ring. I am going to test and see if that provides a sufficient seal. Just in case it does not, I have cut my own gasket from some gasket material. I didn't put it in, but I am hanging on to it just in case.

Does She Breath Fire?

So I went back into the carburetors and tried to figure out what went wrong, what caused them to leak fuel all over last night. I tore them apart and did a more aggressive overhaul than last time. I removed the jets and did a more thorough cleaning. I adjusted one of the floats. When I reassembled them and turned the fuel back on, one of them started leaking again out of an overflow vent. I tried a trick I read about online described as a "trail-side repair". They mentioned knocking on the side of the float bowl with a piece of wood to unstick a stuck float. This worked like a charm. Then I tried again to start the bike.Remember, it hasn't been started in 25 years.

1st Attempt to Start It Up

With the fuel system fairly well restored and with a few other initial items done (Marvel Mystery Oil in the top of the cylinders, new plugs gapped and installed, fresh oil, etc.) I decided it was time to try and fire up the bike. Now, there are still a lot of reasons why she might not run. But this is just for diagnostic purposes.

Title and Registration

Changing over the title and registering the bike turned out to be a bit tricky. But I finally got it taken care of. Since the bike is of sufficient age (more than 30 years old), I was able to register it as a collector's vehicle. This carries with it a few stipulations, including that it can only be driven to shows, club events, or occasional Sunday drives. But the upside is that it is now registered for life and does not require re-registration.

Additionally, rather than purchasing new collector's plates, I was able to use "restored plates". Basically I cleaned up the old green Washington plates that were already on the bike and am allowed to display those. Here is a web-blurred pic of the plate so that you can see the style that I mean.

One interesting note, the guy at the DOL told me, "I have some instructions for you." He told me that, if I get pulled over, for any reason, and a police officer runs my plates, no record will be returned. He told me that the bike plate is registered as "equipment". He showed me the actual number (and symbol) on the registration that they will need to run. He explained that some officers will be familiar with this procedure, some will not. Huh, it sounded odd, but I took him at his word.

Electrolysis Update

It worked! At least well enough. I let the process run for about 3 days, but it had pretty much run its course in 2. Here is another video of the process, well, in process (about 17 hours in):

Regrettably I forgot to take a good before shot. However, here is a picture of the inside of the lid that gives a pretty good indication of what the inside of the tank looked like.

As you can see, it was pretty well covered with rust. Here is a shot of the inside of the tank afterward. It isn't one smooth uniform color. There are still darker patches. But those darker patches don't really look like rust. Though I can't really say exactly what they are.

Not perfect, but a vast improvement. I will call this good enough.

Perhaps not perfect, but good enough for a 40+ year old bike. As additional precaution, I am adding a new petcock with new in-tank screen and new petcock screen. Plus I am going to add inline fuel filters which the bike did not have originally.

Here is what the electrolyte solution looked like when I changed it out half way through the process.

Possible Electrolysis Improvement

Initially, when I first powered up the circuit, I was seeing about a 4A current draw. But this dropped off significantly as the rust particles began to build up on the anode. If you think about it, I am trying to remove rust from a relatively large surface area and collect it on an anode with a relatively small surface area. Frequent cleaning of the anode will help. But I may also consider changing to a different anode with more surface area, perhaps a flat metal bar, or something with many branches like a tv aerial.

Because Science is Cool

After many attempts I finally got the old fuel out of the tank, or at least the bulk of it. The final solution that seemed to work was denatured alcohol. But to be fair, I'm not sure if the success should be attributed to that particular solvent or to the duration of soak. I let it soak for 3 or 4 days which is considerably longer than I allowed any of the previous solvents to work.

Now that the sticky mess is out of the tank, I can more easily attack the rust. There are many methods I could try for this step as well (including a repeat of the dryer method I tried earlier). But the method that sounded the most interesting was the use of electrolysis. I made a couple of videos that explain the basic setup that I am using for this.

As explained in the above videos, I used a sodium carbonate and water solution as my electrolyte and a regular 12V automotive battery charger as my power source. The initial current draw upon supplying power to this setup was about 4A, though it dropped off over time (which I will mention in a subsequent post). The electrolyte began to bubble almost immediately and a brownish foam formed at the mouth of the tank. Below is picture of the anode after about 7 hours. Remember a couple of things; 1. rust from the tank is transferred to the anode, and 2. this is just the beginning, the process will probably take days.

anode before electrolysis (for comparison)

anode after about 7 hours of electrolysis

Carb Cleaning - What I Did Wrong

So I just watched a video on carburetor cleaning. I see that I made several mistakes, including:

• There are several other jets I should probably have cleaned besides the main jets.
• I should probably have tried to remove the jets and soaked them. While I cleared the center hole on the main jets, they have holes along their sides that can only be accessed by removing them.
• I should not have used carb cleaner on the float bowl. It is corrosive to the seal. That could cost me the price of a rebuild kit on both carbs. We shall see.
• I checked the needle valve for free movement, but not the little spring pin that may be in the center of it.

I have not yet decided whether or not to crack them back open at this point to try and correct these oversights. I may wait and see if I need to or not. As I mentioned before, my guess is that I will need to do a proper rebuild at some point anyway. Perhaps it is time to try and source a repair manual for this bike.

Possible Intervention Required

OK, so I may have a problem. I went to my dentist today for a 6 month cleaning. At the end of my visit, as is their custom, they gave me a new toothbrush. But what went through my head was, "sweet, new parts cleaning brush!"

Cleaning the Carbs

So far, for cleaning the gas tank, I've tried several solvents including acetone, new gas, mineral spirits, and carb cleaner. I've tried inserting several sorts of objects into the tank before agitating including ball bearings, nuts, and fish tank gravel. I've even tried using the dyer to agitate the tank. While I'm making some progress, so far I haven't found any magical solution. I found a post online claiming that denatured alcohol would dissolve the old varnished fuel, but that it takes a long time. So I've now put a quart or so of denatured alcohol in my tank (most of the remaining gunk is at the bottom) and I am just going to let it sit for a few days. In the meantime I decided to take a look at the carburetors.

I popped the float bowl off of the bottom of one of the carbs and took a look inside. It had some pretty nasty stuff inside. I decided that I was going to have to take the carbs off of the bike to clean them out. They probably need a complete rebuild. But for now I am going to try and get away with a cleaning.

First, I had trouble removing the carbs from the bike. The throttle cables on this bike are not attached to the carbs externally, but rather go inside the carb and attach to a piston that is moved up and down inside of the carburetor by the twisting of the throttle lever. The cable cannot be detached (and therefore the carbs cannot be removed) unless the pistons are removed from the carbs. However, on both carbs these pistons were frozen in place. After some wresting and liberal use of carb cleaner I managed to get them free.

Piston in carb that is attached to throttle cable

Here are some pics of the carburetors removed from bike and before and after cleaning pics. I'm not sure if I cleaned everything I needed to, but I did make sure that, for each carb, the main jet was clear, the needle valve moved, the floats were free of goo, and as I mentioned before, the throttle piston was free.

The carbs removed from the bike

Junk in the float bowl

Junk on the bottom of the float

Clean bowl

Reasonably clean floats, jet, etc.

Mechanical Agitation - Round 2 (Where the Tank Gets Really Agitated)

Step 1, remove petcock from bottom of tank. This provided another peek at the state of the fuel in the tank.

This time I wasn't going to mess around with the manual shake-shake-shake. I needed a more serious, mechanical method of providing the agitating action. I decided to try a method I saw on YouTube where a guy filled the tank with objects to scour the inside of the tank while rotating it in an ordinary clothes dryer. Here is a video clip and a few pics to illustrate the setup.

The tank in a nice secure bundle

Tank bundle in the dryer

Dryer half packed in with filler

Dryer packed and ready to begin tank agitation

OK, so I dried out the tank as best I could, added about 2/3 of the bag of fish tank gravel, and spun it in the dryer for an hour (air only, no heat), rotating it half way through. I had high hopes for this process. In the YouTube video that I watched, when the guy was done spinning his tank in the dryer, he dumped out a big pile of pulverized rust powder. This is what I was expecting. This is what I got.

Although you cannot actually see into the tank in the video, trust me that it is still filthy. I did manage to find 15 of the original 18 ball bearings. Well, back to the drawing board I guess.

Mechanical Agitation - Round 1

I have a multi-stage plan for getting the gunk and the rust out of the tank. In step 1 I was primarily concerned with getting out the old fuel. I used a couple of cups of acetone as well as a handful of ball-bearings. I was careful to count the ball bearings before adding them to the tank so that I could later be sure that I had removed them all. Here they are, all 18 of them.

I let the acetone soak for a while, with the tank sitting on each side. Then I agitated the tank by manually shaking it. Then I dumped the acetone into a container, through a screen to capture the bearings. I counted the bearings, beginning with zero, until I reached ... zero. None of them came out. They are all still trapped in the gunk and debris. Clearly more cleanings are required.

Tank Cleaning Begins

I took the gas tank off of the bike to begin cleaning.

While removing the fuel lines from the fuel cock assembly, one came off clean, the other not so much. Instead of the line coming off of the metal nipple, the nipple came off with the line. Hmmm, this could turn out to be a problem later, we shall see.

I dumped out the old fuel. It came out a nasty brown/black mess. But what is worse, the tank is full of big chunks of rust.