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.