Saturday, December 18, 2010


In an attempt to figure out the revs on Salty, I picked up a cheap little tachometer from Prohoists. It is self-powered, and pretty darn easy to install. The pickup signal wire wraps around the main coil lead, and ground wire mounts to a chassis ground. The end.

And it works. I've heard I might need to play with how many times the signal wire wraps around the coil wire, but so far it seems to work. It might reading a tad high, but I want to borrow the wireless tach from work to compare the two before getting it dialed in.

I built a quick little aluminum mount that attaches to the steering stem. I still need to pickup a couple small bolts to mount the unit to the bracket I built.


Thursday, December 2, 2010

Drilling Jets

I decided to get myself setup to drill out the main jet on the Mikuni mounted on Salty. As it happens, I also have been dialing in the tuning on the same model of carb mounted on the 140cc chinese engine I have in my Trail 55 rat bike project.

I came across this fantastic page, which saved me the time and effort of converting the numbers and matching up the drill sizes:

As luck would have it, I had picked up a cheap drill bit set from Harbor Freight last month, just to fill in some gaps I had with other drill bit sets.

Salty's carb had a 95 main jet, and is acting as if it too lean. I've had to move the needle clip to the bottom most position to get it to pull at part throttle, yet it totally falls flat at wide open throttle. My spark plug is also too light in color after I did a few spark cuts.

Ratty's carb came with a 97.5 main jet, and has always acted very lean at part throttle application. Almost like a lean surge you would feel with a weber carb on a car when it was too lean.

So I made up a little aluminum block fixture to mount the main jet in, which fits nicely in my bench vise. I made a one jet size increase at a time (or as close as I can get) so I used a #60 drill bit for Salty, and a #59 for Ratty. The process was very easy and quick. I can remove the carb, take off the bottom half and have the main jet in my fixture in less than 5 minutes.

Unfortunately, I've had no daylight hours to run either bike since I drilled the jets. And the weather has started to turn a bit rainy this evening. Hopefully I can get out on the road this weekend and try to dial things in.


Thursday, November 25, 2010

More Jetting Notes

So...I was completely wrong in thinking I was running rich in the mid range. After adjusting the needle clip up two grooves (making it leaner), I went for a ride. It was terrible. It wouldn't take throttle at lower rpm, and would lose power at 3/4 throttle. I was able to clear it up by adding some choke, which adds fuel.

I rode home, and adjusted the needle clip to the lowest of the five groove positions, making it full rich. It responded instantly. It now runs great through the rpm range, even capable of pulling from a stop in 2nd gear. It is amazing how much of an effect such a small change can have.

As a reminder, here is the diagram of the needle clip arrangement:

The only issue I'm seeing now is I'm puking a bit of oil out both the main crankcase vent, and around the dipstick. Now I see why they made aftermarket breathers that screwed into the dip stick opening. I'll have to scan ebay for such a device.


Wednesday, November 24, 2010

Mikuni Carb Adjustments

I've been tinkering with the jetting on Salty the past couple days, and have had a couple old Honda enthusiasts show interest in how this larger 24mm Mikuni will work on a small 50cc Honda. I'm curious too, and have only begun to start messing with things.

First, I wanted to link everyone to this page:

This is a fantastic primer on how a typical Mikuni motorcycle carb functions.

The first two times I've run Salty, it was very boggy at lower rpm. This was compounded by the fact I have it geared very tall, using a 16-tooth front sprocket, a stock 40-tooth rear sprocket, and the taller 2.75"x17" rear tire. I'm also running a 1/4-turn throttle mechanism, which reacts much quicker than a typical slide throttle.

Pulling away from a stop wasn't easy. It would bog very badly unless I gave it a little Fred Flinstone action to get rolling. It also ran very poorly at low rpm in second gear, when trying to pull away from slower turns.

So I started by adjusting the pilot circuit, as this has the biggest effect on low speed, and low throttle opening running. Usually this screw is set at 1.5 to 2 turns out from all the way in. In my case, it was set at 1.5 turns out. After getting the bike warmed up, and with a decent idle, you simply turn the adjustment screw in or out, and you'll be able to hear/feel a change in idle speed. In my case, it was rather dramatic, as turning the screw out (making it leaner) raised the rpm quite a bit. If you go too far, the rpm will start to lower. So you get a feel for where to set it based on rpm. In my case, I settled on 2.5 turns out. I then adjusted the idle speed back to where I wanted it.

It immediately improved throttle response. Even with the bike just sitting in neutral at an idle, it was very boggy before. Now it just revs clean with no hesitation. I then went for a short ride. It was dramatically improved, especially pulling away from slow turns in 2nd gear at lower rpm.

I now need to turn my attention to full throttle use, as it isn't quite right. I have a feeling I'm quite rich overall, especially since I needed to lean it out so much even at small throttle openings. When I'm cruising at mid to upper rpm in second gear, it pulls very nicely as I open the throttle. But I notice the last 10-15% of the throttle opening makes zero difference to acceleration. If anything, it feels like it stumbles a bit. A check of the plug indicates it is running rich. Going from 3/4 to full throttle opening is right in the transition range between the needle and main jet circuits.

I don't have any spare main jets, so I'll need to order some. In the meantime, I thought I would play with the needle jet position (1/4 to 3/4 throttle mixture) by adjusting the needle clip position leaner. I'm currently set in the middle of 5 clip positions. so I'll move it up a clip and see what that feels like.

If it isn't too cold tomorrow, I might go for a short ride.


Monday, November 22, 2010

Brake Light and Another Ride

I wanted to throw a brake light on Salty, so I could run him on the street. I never really thought about that when I made the seat/cowl though, so I needed a simple solution. Thanks to my previous experience doing a taillight for my rat bike project this spring, I decided to use a simple 9V battery as the power source. This way I don't have to tap into the lighting coil and worry about the rectifier with the stock wiring loom.

The end result is a 9V battery, a 9V battery holder, some wire, a stock rear brake light switch, and a pair of 1/2" push-in red lights. All the components are housed in the left side pod cover, and runs through the seat in plastic tubing to avoid and chaffing on the fiberglass. The lights simply push through a 1/2" hole I drilled in the bottom edge of the seat cowl, as shown below:

The lights are actually quite bright when viewed from behind.

After completing that task, I took another ride around the north part of town. I've learned a few things riding it:

-I need to move the pegs a couple inches lower, or a couple inches further back, or a combination of the two. I'm just too cramped.

-Having the bike geared so tall means that 2nd gear isn't that usable for putting around city streets. 1st is too short, 2nd is too long, especially for slower speed corners. I think I'm going to throw a smaller front sprocket on the bike, which luckily doesn't take much time.

-This bike is fun! It doesn't have the scoot of the rat bike, but being all hunched over and close to the ground makes it exciting, even at 40mph.


Sunday, November 21, 2010

Kickstand and Number

I finally got off my duff today around 1pm, and did a bit of work to Salty. Job one was to make up a kickstand, to replace the center stand. Centerstands are great for performing maintenance, but they are difficult to work around. Usually the exhaust, chain, and rear brake levers all have to be positioned just right to avoid interfering with the centerstand.

In my case, the only thing that interfered was the rear brake lever. I had built it with the centerstand down, not realizing it would swing up against the brake lever with the bike on its wheels. The easiest solution was to just take the damn thing off! I can still slide it under the bike if I want to use it for maintenance, but I built up a simple little kickstand for day-to-day use.

I had found a $7 kickstand made for a kiddy bicycle at Wally World a few week ago, which I installed on the Trials bike. As luck would have it, the K-Mart just down the street had the exact same unit. I bolted it right under the motor (where the stock footpegs normally bolt) and shortened it a tad to be the correct length. I topped it off by welding on a washer to give it a bit more contact area with the ground.

Job number two was to finally put some class letters/numbers on the number plates I had built many moons ago. In this case, M-PG 50. Modified chassis, Pushrod Gas, 50cc.


Saturday, November 20, 2010

Chain Cover

I spent a little time in the garage today working on Salty. It is about 45-degrees out, rainy and windy, but luckily the garage is warm! I raised the front ride height about 1/2", as I found the front shocks wanted to just barely bottom-out on small bumps. That wasn't difficult, just fiddly.

The other thing I did was take on old chain cover from the parts bin, clean it up, fit it, and paint it. These early Hondas had a fully enclosed chain cover to keep the oil from flinging off the chain and onto the bike, and keep dirt/grunge from getting onto the chain. Usually these covers are ditched the first time the chain is adjusted or replaced.

The cover is in two pieces, a top and bottom. Each piece bolts to the swingarm, and then they fit into each other for a tight fit.


Friday, November 19, 2010

Riding Salty for the First Time!

After many months of little issues, combined with the fact I built up another complete bike (the Trials bike) I finally got back to Salty the past couple days. I had it running, but not very well many months ago. It was running very strangely, and sporadically. Sometimes it would kick over first try, other times I would wear my leg out trying to kick it over. If I got it running, I could never get it to hold an idle without needing the choke fueling circuit on, which of course raised the revs up high enough. So basically, I've been troubleshooting little issues and not having a lot of luck isolating the main problem. It wasn't fun dealing with the same problems everytime I turned my attention to it, so I moved on to other projects.

Yesterday I decided to take off the complete carb/manifold/fuel line and do a thorough cleaning. I drained the tank and didn't see any sediment. I built up a new fuel line with a small fuel filter, which it didn't have before. I also disassembled the carb and gave it a douche, even though it looked spotless inside. I put everything back on, and it fired up fairly easily. It still hunted a lot while trying to fast idle. Then, as I was glancing down at the ground, I hurt it sputter and I saw a little puff of moisture shoot out around the base of the intake manifold I had built. It kept sputtering, and shooting out. It was obvious there was a little crack in the intake manifold where I had welded it together. For a refresher, here is the manifold I built:

The "left" side of the manifold is where it bolts to the cylinder head. It is a very tight fit between the pipe and the nuts that secure it, so I had to file away a bit of meat. I also apparently didn't do a fantastic job welding it in that area, as the crack formed right there.

Guess what? I did a shitty job welding two intake manifolds. I had built a test manifold before this one, to get all my angles and dimensions correct. So I grabbed it out of the bin, and bolted everything back up. Salty fired on the first kick, and ran great for about 2 minutes, holding a perfect idle and taking throttle. Then I heard it stumble and saw a puff from the same exact location! What the hell. I think I'm just cracking what little weld is there as I tighten the nuts to secure it to the head. Two manifolds down. But at least I maybe found my mystery problem?

Instead of trying to fix both manifolds, or make a new one, I thought of some better solutions. One of which uses a stock C110 intake manifold, which I happen to now own three of. The two C110 parts bikes I grabbed from Ashland for $50 each had one. The problem is, this manifold is designed to use a small section of rubber hose that clamps to a round section of the stock C110 carb. The Mikuni I'm using has a bolt-on flange. So I have a few options. I can make up a new flange and have it welded to the stock C110 item. Which may be the best long term solution. I don't weld aluminum, however, so I'll need to find someone to do that for me though. I'll likely have two built.

The short term solution was to hack off the carb side of one of the manifolds I built. This side has a much wider hole spacing for the two mounting bolts, so I have a very good welded connection there. I then connected this piece to the stock c110 intake with a piece of 7/8" ID fuel hose I had. It is a very snug fit, and with a few ugly hose clamps it fits and feels secure.

It worked too, as the bike fired right up, held an idle, and even held a nice low rpm idle with no choke after it warmed up. It takes throttle well too. So of course, I grabbed my helmet and realized I was going to actually ride Salty for the first time. I was never able to get it running well enough to want to try.

So I did. I blasted up and down the road a few times, going through all the gears. It actually runs on the road now! I was very excited. It wants to bog a bit right off idle, but if I'm smooth with the throttle and give it a quick paddle or two to get it rolling, I can accelerate off. The engine in the bike is a 3-spd auto clutch, with a large front sprocket. So first gear is a bit tall, and I think the 1/4-turn throttle I have on it is a just a bit too quick reacting. I'm sure I'll get a bit smoother as I ride it more.

So there you have it, Salty not only seems to run, but it goes down the road. It isn't the most comfortable bike in the world, but it is actually doable on the road. I just fold up my long legs, hunch over, and go for it. I'm going to fiddle with a few more things this afternoon, and hopefully take him around the block more before the rain comes this weekend.


Saturday, July 3, 2010

Proof it Runs

After a few minutes of tinkering, I got Salty to kick over easier, rev a bit cleaner, and eventually idle fairly smoothly. Here is me tinkering:

And proof it runs! I'm thinking of renaming him Smokey, as he tends to smoke a little. Probably a bit of blow by the freshly honed cylinder and new rings. And I think I squirted quite a bit of magic oil in the cylinder last year so as not to turn it over dry.

I still need to build a shift lever and adjust the auto-clutch before I can see if it motivates down the road under its own power. But at least it manages to run and idle better.


Friday, July 2, 2010

De-Gunked Engine and Freshly Sealed Side Cover

I whipped off the side cover on Salty's engine, and gave it a good thorough douching inside and out. There was about half a gasket stuck to the case, so that took some scraping and wire brushing to get it off. I also cleaned up the mating surface on the engine, and gave the entire area a good spray cleaning and brushing.

It was much cleaner that I thought it would be, as witnessed by the photos below:

I used some permatex gasket sealer on the mating surface and installed the side cover. I pulled out my trusty in-lb torque wrench and carefully went around the bolts a few times until everything was snug.

I figure I'll wait till morning to fill it with oil, and then get back to running it a little and dialing in the idle and mixture settings.


Thursday, July 1, 2010

It Runs!

After work tonight, I started playing in the garage. I had several small fixes in mind for Salty, but didn't think I would be trying to get him up and running. Somehow, things just came together, and the end result is a running engine!

Fix number one was to modify the center stand return spring plate. When I built the rear brake arm, I apparently fit everything with the bike sitting up on its center stand. Unfortunately, when I lowered it down on both wheels, the little "C" shaped bracket that attaches to the frame and the return spring interfered against the brake arm. A little grinding, drilling a new upper locating hole, and some fiddling, and I got everything to work together.

Then I installed the spark plug and fit a kick start lever from some random bike with just enough "curve" in its shape to clear the exhaust. After that, I decided to put a small amount of fuel in the tank to see if the rebuilt petcock I had mounted worked and held fuel. After a few minutes of no drips, I then decided to fill the crankcase with oil.

I gave it a few slow kicks to get the oil circulated and noticed a few small leaks around the "passenger" side case. Then it hit me, that I never made a gasket for that side case. I had simply fit it on loosely when mocking up the exhaust. It didn't leak bad, but had enough drips to where I'll need to pull it off and make a gasket. Or I'll just use some gasket sealer snot.

So, I had a carb getting fuel, a spark plug getting spark, and a bottom end with oil. Well hot damn, I guess I better take it outside and see if it starts.

As a reminder, the engine in Salty right now is sort of a Frankenstein. It is an old ass Cub 50 bottom end, with the 3-speed auto clutch. And by old ass, I mean it came out of a parts bike and had a thick oozy goop coating the insides. I "washed" out the innards and soaked it in the solvent tank for a few days at work. It turns over, but other than that, I have no idea how the bearings and trans looks.

Then I mounted fresh top ends parts, which are the main hot rod items on the motor. In this case, I'm using one of the two freshly honed standard bore cylinders that I had 0.040" milled off the top of the barrel. Combined with the ported C110 aluminum cylinder head that has a matching 0.040" milled off the bottom mating surface, that raises the compression from 9:1 to around 12:1. I also fit stock sized lightened valves, lightened rocker arms, and used, but nicely cleaned up stock piston with new rings. Like I said, a Frankenstein engine I figured would be perfect for just using to mount up in the chassis and build stuff around. If it wants to actually run, then that would be cool too. So my expectations were pretty low at this point.

A big part of getting Salty up to record speeds will be the gearing. Last year, I spent a lot of time making a spreadsheet to determine speed in gear for both the C100 3-speed trans and C110 4-speed trans. I've long since forgotten the outcome, but I think both the 3-spd and 4-spd have similar top gears ratios, so if I could get up to speed using the semi-auto 3-spd, then I didn't have to worry about mounting up and building a clutch cable.

So, short story made super long, Salty runs. It took a while to kick over because I realized my throttle cable adjustment was too "tight" so the throttle barrel was lifted a little in the carb. Essentially, it was as if I was holding open the throttle. After solving that, I gave it a little choke and it fired right up, and revved to about 90,000rpm. It was probably only 4,000rpm, but god damn was it loud! I fiddled with the choke a little, and adjusted the idle screw until it sort of settled down. It wasn't running real great, and wouldn't hold an idle, so it eventually died.

Then a few minutes later Susan got home, so I started it up for her. And of course it ran better, so I assume a little bit of heat and a few more adjustments to the idle and mixture screw, and it almost settled into a normal idle. It even revved fairly clean through its range a few times.

I immediately grabbed the oil drain pan and pulled the drain plug to drop the oil, since I'll need to seal up that out case cover. And of course Susan got a photo of my triumphant moment:

It still isn't quite road worthy yet. Obviously I need to fix the leaky side cover, put oil back in it, get it to run a bit better and hold an idle. Besides that, I need to fit a chain, do a full nut and bolt job on the entire bike to make sure nothing rattles off, and then do it again to make sure i haven't forgotten anything. Maybe this weekend I'll get to ride him down the street.


Sunday, June 27, 2010

Throttle Cable and Fuel Lines

I've actually done a few little things on Salty over the past couple weeks, but nothing exciting enough to really report on its own. I had rebuilt the stock petcock and mounted it, got the intake manifold mounted, and ran some fuel lines.

Since it was 100-degrees outside this afternoon, I thought the living room would make a great garage space, so that I could build and mount a throttle cable. Luckily, Susan didn't mind as she was busy surfing the vast internets for dinner recipes:

I had this 1/4-turn throttle assembly in the spares box, and I modified a C100 throttle cable to fit:

With the help of Tom Cruise I got it all wrapped up:

I'm getting real close to seeing if this thing fires up.just a few more minor details to take care of.


Wednesday, March 24, 2010

Sparky McSparky!

After a bit of fiddling with various stators and coils, I finally got some spark to the plug. Apparently I have about four different stator assemblies, two different ignition coils, and a random selection of harnesses. What I had in the bike was a mixture of I don't know what, and it wasn't working.

So I grabbed the stator off the original C110 engine and cleaned it up. It really didn't take much effort, as I just ran some emery through the points, lubed the little foam pad, and blew the crud out with some compressed air. After I installed it, I mounted the stock C110 coil and ran a few wires. I don't plan on running any lights on Salty, so I didn't use the stock harness or key assembly.

I found this wiring diagram online here:

I isolated the ignition circuit and just a ran a simple on/off toggle switch up to the headstock area. The switch is grounded, so that turning it "on" releases it from ground, and the magic sparks happen.

I was pretty excited to see the sparkplug spark. So much so, I called my pops right away, since he was over last night doing some troubleshooting with me.


Sunday, February 28, 2010

Front Number Plate

I've actually been fiddling with Salty a bit the past week, but don't have much to show for it. One of the items I did manage to complete was a front number plate. Which is pretty much a piece of plastic cut to shape. I'm not exactly sure why it took several days to put together this little item, but it did!

At least Salty has had some company, since Ratty has been hanging out next to him.


Tuesday, February 23, 2010

Dirty Magneto is Dirty

I pulled the flywheel off a couple days ago, so I could get into the general flywheel/magneto area and do some cleaning. I took about half a pound of grunge off the inside of the flywheel, and began the dis-assembly and cleaning of the stator assembly.

The entire stator assembly comes off with a couple machine screws, and this is what I found:

Since I have a few extra engines, I grabbed a spare stator assembly that was in much better shape. I've already R&R'd the contact points, and will finish cleaning up the rest of the assembly tomorrow.

The "fresher" assembly:


Monday, February 22, 2010

Flywheel Puller

I realized I had no way to pull a flywheel off the C100/105/110 engine, so instead of trying to fab up some puller, I hit the easy button and ordered one via the internets. After some quick searching, I came across a unit that apparently fits about 1 million other types of bikes. I picked it up from Heartland Products.

The big threaded boss threads into the flywheel, and the smaller section gets turned up against the end of the crankshaft. A couple gentle turns, and the flywheel popped right off. Be sure to keep track of the tiny woodruff key.

Chris H.

Wednesday, February 17, 2010

Salty, Front & Center

A few things got arranged tonight, so Salty has some room to work.

Tuesday, February 16, 2010

Long Time No Salty

It has been well over a year since I've blogged about Salty. Unfortunately, that also means I haven't touched the bike for a year either. It is sitting comfortably in the garage between the Bridgestone Sport 90 and the Hodaka ACE 90. Looking lonely.

Over the previous winter, I decided to build a new race motor for the Formula Vee. This was something new for me, so I took my time on it. I had the engine in the car running, about a week away from my first race date, when a rod bearing decided he wasn't happy. I pretty much pouted for a week, then pulled the engine out and tore it down. It was very obvious what had happened. I then spent the next couple months building up the engine again, this time with success.

I built an engine stand to run the engine on before putting it in the car. It ran great. Luckily, it also ran great in the car. I've made two race days with it, which also meant a bit of fine tuning to the cooling system (scoops and oil coolers) and a few other odds and ends. Before I knew it, it was winter again. I haven't touched the race car for several months, nor have I touched any bikes.

But that will change. My race club is lacking local events early in the year, so I've decided to jump back on Salty over the summer. I don't know if I'll actually get to Bonneville though. I would need to make that a primary objective, schedule vacation, set other projects aside etc. Initially, I just want to get it running and finish him.

I'm also going to finish a few other bikes. The Bridgestone needs a few small touches, I have a Yamaha YG-1T that needs some details too. Basically, I'm going to pull all the bikes out of the garage, walk around them and make a list. If it isn't raining this weekend, I may do that Saturday. I'll also organize the garage and make a real work center for Salty.

So keep posted, as I hope to have more stuff to blog about over the next few months.

Chris H.