I Built a 3 Cylinder TWO STROKE Bicycle (From Scratch)

Hinzugefügt: 2026-05-23

[00:00:00]This is my motorized bicycle with a three-cylinder engine that I developed and built myself over the last 2 years from scratch. But the bike has one problem. It doesn't nearly have the power that it should have. That will change in this video. Today, I will modify the bike. So, it went from running like this to this.

[00:00:26]First, we will start by waking the bike from its winter hibernation. It's been sitting in here for half a year now, and since it's spring and it's getting warmer, it is now time to get the bike running properly. I just finished the bike in the fall of last year, and since I want to drive it before the winter comes, fine-tuning wasn't that important to me. That's why we're taking care of it now. Also, one problem the bike currently has is that something is wrong with the middle carburetor, as it immediately loses fuel as soon as I turn on the fuel tap. I first removed the first carburetor to get better access.

[00:01:01]Then I removed the float chamber and immediately found the problem. Something inside has come loose. After that, I reassembled everything and addressed the actual problem. Back then, I still believe that the problem with the low performance lay in the ignition and how I set the ignition timing. I set the ignition timing in millimeter before top dead center and not in degrees before top dead center, which isn't wrong in itself, but I figured the problem had to lie somewhere. Then I removed the cylinder head of the first cylinder and used a dial gauge to determine the exact top dead center. Then I also set the ignition timing to zero. Then my timing gun arrived. I should have gotten one of those already last year. Anyway, I then had to remove the battery from a super moto. And after studying the instructions for hours, I was finally able to set the ignition timing with the timing gun. After that was done, I wanted to replace the clutch gear assembly because a bolt on the base plate broke off during a trip last year.

[00:01:58]So, I started by disassembling the clutch. After everything was removed, I discovered I could turn the drive shaft back and forth. This is a problem because there shouldn't be any play as the sprocket and chain are currently installed on the other side of the drive shaft. This means that the nut holding the sprocket has come loose. I actually wanted to take a test drive now and see if adjusting the ignition had made any difference in performance. But unfortunately, I now have to remove and disassemble the entire engine to tighten the nuts again. It is what it is. I need to remove the engine anyway to install the new window pistons and the read upgrade kit which I developed during the winter time. These are the read valves of an AM6 engine. And those are my read cases. Of course, they are all billet and are slightly twisted. So, they are as short as possible. They would be longer without the twist because the mounting bolts would be before the re like on the G2 system. And with my style, the bolts are next to the re. So, with this, they are an additional 5 mm shorter than the G2. So, now let's remove the engine, install the read upgrade, and tighten the nuts.

[00:04:52]I have now took the cylinders off and found a nice surprise. Basically, all of my uh connection or bearings are ready to replace. They have a significant amount of up and down play and also side to side play, which means I have to now take the whole engine apart and take also the crank apart and uh change all the crank pins and all the crank bearings, which is not a problem. I just saw that I have uh plenty of Chinese crank bearings and crank pins lying around. I could also just install the new window piston, put on the cylinders, put the engine back in the bike again, and I'm ready to go. But I think this wouldn't last long. And I think after a few weeks or months, the whole engine is basically crap. And to prevent this from happening, I see no other way to replace all the bearings. But then the engine is perfectly as new. And yeah, so let's take the whole engine apart and change the bearings.

[00:06:06]Ha.

[00:06:13]Aha.

[00:07:08]Ha.

[00:10:18]Some days have passed since I've assembled the engine again and also assembled the whole bike. I have to say the read housings looks very good to me.

[00:10:26]It suits the bike really well.

[00:10:28]Unfortunately, I didn't have enough room to also fit air filters because, as you see, it's more than tight. I have absolutely zero space left, but as it is right now, it works. The weather is now finally good enough to take it out for its first test ride. And this is exactly what I'm going to do now. Let's hope that my improvements I made now finally transformed the bike to the monster that it's supposed to be.

[00:11:35]Heat. Heat.

[00:11:55]Heat up here.

[00:12:11]Heat.

[00:12:20]Heat.

[00:12:50]Heat. Heat.

[00:12:55]Heat.

[00:13:11]Heat.

[00:13:30]Go.

[00:13:56]Heat. Heat.

[00:14:24]As you just saw, the bike is absolutely a beast. It drafts absolutely free without any problem at all. I had never expected that those reads would make such a huge difference. It's a huge It's a night and day difference. Without the reach, the bike rev one half of the RPM that it is right now. It's absolutely mind-blowing.

[00:14:50]I always thought the problem was the ignition and the way that I set the ignition, but it was never the problem.

[00:14:58]The only problem was the missing reads.

[00:15:00]I have also ported all the cylinders and not just the bits. I have taken out quite a lot of material out of the cylinders to achieve the timing someone with knowledge given to me. And I think this timing with missing reads was the biggest problem because the engine was not compressing the air fuel mixture as it does right now. After every run, my underside of the seat and all the frame here was covered in fuel, which means that all the fuel that is supposed to be in the crank case was pushed out of the carb and under my seat. So the engine was not compressing the air fuel mixture. It was pushing it out of the carb again. But now I have figured out the problem and also those reads are pretty big. Now we come to the next problems which came up during the test ride. The first problem is that the whole bike is just running with choke on which means that my jets or my pilot jets are too small which is no problem.

[00:15:50]I have a lot of jets lying around and I going to install bigger ones. Next problem is that the bike just dies while riding. I think that this problem lies on the fuel lines. When I look at this fuel line right here, I see it makes a very hard corner and I think not enough fuel is going through this line and the carbs are just running out of fuel. And the last problem is, as you saw in the video, the carb just fell off. I think I cut the rubber which is holding the carb a little bit too short and now it does not have that much surface to hold on to the carb. But otherwise, this first test ride, went really, really well. Nothing broke and I have find just a few minor issues. Now the next step is to order new fuel lines and new rubber so the carb didn't fell off again. So now I have to wait until the package arrive with the new parts and then we're going to install everything and then we're going to make another test. Right. Now everything I've ordered arrived. I going to show you the parts real quick. At first I bought some FL then some elbows for the fuel line.

[00:16:55]Then of course the fuel line and most importantly two new rubber hoses for the carb. Now I going to assemble the new parts and then we going to make a new test ride.

[00:17:53]This is now the finished fuel end system. Honestly, it doesn't look as good with the hose clamps, but it's functional, and that's the most important part.

[00:18:04]I've now fully assembled everything.

[00:18:06]Like I already said, it doesn't look that beautiful, but if everything works, it's fine. And one problem I forgot to mention is that my clutch was slipping quite heavily. I have now adjusted the clutch. I have just pre-loaded the spring more. This is already the BTT clutch from Smolik Performance. It is a 3D dry clutch. And yeah, I have pre-loaded the spring even more. This is already an heavyduty spring. And yeah, let's see if this holds all the power with the adjusted preload. Heat up here.

[00:19:02]Oh, heat.

[00:19:26]Oh, so far so good. At first, I going to start with the positive things. At first, the adjusted preload on the clutch was a very good idea. The clutch was still slipping a little bit, but not as bad as at the first test ride. So, most of the power the engine makes actually goes in the road and not uh dies in the clutch. And also, the fuel line system does also work. So, there's not a problem. It does not leak. It just works. But I think the old one doesn't have a problem because the problem with the dying engine still remains. And now we come to the bad things. I think the engine is still too lean. I still have to lift the choke horn on in order to have the engine running, which means it's still too lean. I have already a 52 pilot jet installed and 110 main jet. At full throttle, there is no problem. So, I think I'm going to continue to make the pilot jet bigger. Unfortunately, I have no bigger pilot jets here, so I have to order one. I think I'm going to install a 60 pilot jet next. So, now I have to wait until the jets arrive. The new jets have now arrived, and I've already installed them. I've also experimented with different jet sizes and settings. It all took some time, but I have now perfectly tuned all the carburetors to the engine. I have also solved the problem with the engine constantly stalling. The problem was the fuel level was too low. The tank was at least third full, but because the fuel line at the third cylinder has a bend upwards, there was insufficient pressure behind it. And from there on, I always make sure that the fuel level is at least 2/3 full. And from there on, I've never had the problem with installing engine again. During the second test ride, it was still audible that the clutch was slipping slightly. I have now increased the spring preload to the maximum. It really can't be increased any further. I have already driven it.

[00:21:28]It still slips a tiny bit, but it is what it is. The engine have probably too much power for the clutch. Anyway, that's the best I could do with it. The bike is now running absolutely perfectly. It even runs without the choke on as the carburetor chat settings is now perfect. The bike also now idles steadily which it never did before. I've already started this project 2 years ago and it is finally running perfectly. So now after 2 years I've now taken the test drive you all have been waiting for.

[00:22:17]Heat. Heat.

[00:22:39]Heat. Heat.

[00:22:53]Heat up here.

[00:23:38]As you've seen, the bike is now running absolutely perfectly. I have also installed an RPM meter so you can see now how high the engine is actually reving. I have also got myself a speedometer so we can all see what the bike's top speed is. So now after 2 years we finally know how fast the bike can go. So now let's hop on and see what this engine is capable of.

[00:24:06]Unfortunately this will not happen. The engine is broken. Let me explain.

[00:24:16]Before I wanted to do the top speed run, I took a short test ride and played around with the carburetor settings a bit. Unfortunately, I didn't record that. I was driving slowly and only for very short distance. Then the bike wouldn't hold its idle anymore, and the engine was starting to behaving strangely. Then I turned it off and checked everything looking for a fault, but I didn't find anything. I tried to start it again, but the engine was running on just one cylinder and the bike was misfiring. I've also heard a grinding noise when starting it. At first, I thought one piston had rubbed.

[00:24:50]Then I cycled back home and removed all the cylinder heads. There we are now seeing that only one crankshaft is turning. The first two pistons are stationary. That means I've snapped the crankshaft between the second and third cylinder. So, what exactly does that mean for the bike and for the engine?

[00:25:08]Well, last year after the bike was finished, but still didn't have much power, I rode it a lot. I also recorded a lot, but since the videos of me just cruising around slowly are pretty boring, I won't posting any more of those. I still have a lot of footage left over from last year, but I probably delete it all eventually. In any case, I easily drove 500 km on the engine last year without having any problems. The engine did run great, but doesn't rev high and doesn't develop any real power.

[00:25:38]Then I did the read upgrade and installed the windowed pistons. A month later, the engine is now broken. I should mention that I also drove a few times without the camera and basically always pushed the engine to its limits.

[00:25:50]That was too much though, too much refs and too much power. It was only a matter of time, but I didn't expected it will happen so quickly. I had hoped it would last a little bit longer. At least I wanted to do the top speedrun with the speedometer. So why don't just fix it again? Let me explain it this way. If all three engine cases are side by side and all the crankshafts are connected, but no engine mount is installed and my connecting rods aren't attached and I turn the engine, you can see all three engine cases move independently from each other. The engine mount and my connecting rods stiffen the casings relative to each other and prevent any movement. This puts a lot of stress on the engine causing it to become very strained. That's due to the Chinese quality. But honestly, the engine was never designed for something like this.

[00:26:38]Obviously, I'm now in a dilemma. I can of course fix the engine again. That's absolutely no problem. I even want to repair it again. But it won't last long again because it's simply putting too much strain on the crankshaft. Of course, I just could go back to driving around slowly, but no one really cares or is interested in this sort of videos.

[00:26:59]As you can see, it's a really tough dilemma. I can't sell it for high price because it's not really a good engine, but I also can't sell it cheaply because so much money and effort and two years of work went into it. Besides, I don't really want to sell it because the bike looks absolutely beautiful with it and the engine is part of me and the channel. If you have any idea what I should do with the engine, let me know in the comments below. I've been working on this engine for two years now. I assembled it and put it back together at least 10 times. I'm really exhausted from it and I really need a break from this engine. So, I've decided to leave this engine broken for a while and turn my attention to a new project. I have also happened to have three stage 6 Pio MK2 racing cylinders lying around. I just happen to have ordered three connection rock kits for them. Also, purely by chance, I have a 3D clutch lying around. And coincidentally, I have the knowledge to develop and build a complete three-cylinder billet crankshaft and also the corresponding engine block. But as I said, it's just a coincidence. So, that's settled. Then, what's next for the rest of the bike?

[00:28:04]Since I've currently waiting for the crankshaft parts for my billet 6-speed MXS twin cylinder project and I have gotten pretty bored, I have quickly developed a new engine for the bike which is sitting in my mind for ages. I mean, when you look at the left, you can already see it.

[00:28:23]Yeah. So, there is it. I didn't even take a week for this, but I have to say it's not completely finished yet. But also, it's not that far from finished.

[00:28:33]So, more of this in maybe the next video. So, as always, stay tuned and see you next time.