We Built a 670cc Harbor Freight Mini Truck From Scratch… FIRST DRIVE

Added: 2026-05-05

[00:00:00]All righty, fellas. Last time we worked on the mini truck, we built custom miniature fourlink suspension and a never ever seen before hybrid four-wheel drive system. But this is the most important week because we're going to be seeing if all of those systems work and hopefully at the end of the video getting this thing to drive for the very first time. Now, it's really important that this thing does drive because we've got the most diabolical adventure planned for it. And if it breaks down, we're going to be stuck in the middle of nowhere with no way home. Now, before we dive into all this complicated stuff, I want to tackle one thing that historically we're very bad at, and that's a seat. If you look in here right now, there's really nowhere to sit. And usually when we design our seats, we make it very crammed and very uncomfortable. So, this one, I want everyone to fit in, and I want it to be very drivable. And I think the perfect candidate is over here in the graveyard, the mini trophy truck seat. Now, I'm thinking the way we're going to mount this seat is right over the axle. And then your body weight is going to kind of give this thing like a 50/50 weight distribution.

[00:01:06]>> Well, that would be nice.

[00:01:07]>> Which would be pretty nice. Let's see what it's going to feel like, though.

[00:01:11]>> Can you kind of fold yourself up?

[00:01:13]>> I have the leg room is the real question.

[00:01:18]>> It's a lot more comfortable than a normal go-kart seat. Now, we've just got to figure out a mount for it. Now, we're going to be using the easy method to mount this thing and using something that's already been provided to us, and that is this seat extension that came with the mini trophy truck. I think it's for kids. It made sitting in the trophy truck impossible, so we took it out. But now we have it, and this seat bolts perfectly up to it. So, what I think we're going to do is take the top section of this square with the seat bolt mounts on it. You can kind of see that they're angled. So, that'd be complicated to make, but we already have it. So, we'll cut this apart and repurpose it in the little truck.

[00:02:03]Now that we've got this thing cut and cleaned up, this is how we're going to mount it. We're going to have some tubes coming off this support over here. And I'm going to angle this bracket so that when we bolt the seat up, it's laid back a little bit. And that's going to give you a whole bunch more room. And that's super important in this machine. All right, this seat mount is looking pretty good. Now, we've just got to support the back because right now it's only supported from the front. It's actually pretty strong, but I don't have faith in it over bumps and jumps. So, what we're going to do, I was thinking we were going to take some tube from the back, but that's going to be a really complicated angle to get that to sit at.

[00:02:37]So, I'm going to do is I'm going to head over to the Arc Droid. And I think we already have some tabs that is going to work perfect for this. Now, we've built so many things on the Arc Droid now that we have a stack of over 200 creations on here.

[00:02:50]>> 200 >> 200. But I think this one labeled mounts are the suspension mounts on the mini truck. So, we'll just reuse those. And these are already made for a 1-in bar, and they'll slide right on, and we can weld them up.

[00:03:17]Well, we got one and the others scoundrel down into the pit of despair.

[00:03:22]Look down there. Look how much crud is down there.

[00:03:29]Oh, that's the next one we need. And now that we've got these tabs, I can show you where they're going to go. It's going to be quite simple, but I think it's going to work out great. So, if I can situate this, it's going to go something like that. And then we'll just fill that space with well, well, they're in there. They're in there a little crooked, but I found if you just say it's by design, then people just have to take it for what it is. And now we can get that seat in here, see how it fits.

[00:03:59]Dude, that seat's not going anywhere.

[00:04:01]>> That looks mighty solid.

[00:04:03]>> That is the most solid seat. Honestly, the best looking seat that we've ever made in any vehicle. I think you got to get in there and see how it's going to fit. Because I'm bigger than you, do I have to try it out first?

[00:04:15]>> Yeah, Taylor's the test dummy. Because usually I just build machines so I can fit in them.

[00:04:21]>> But now I get to fit. I think Wow, this is actually really nice.

[00:04:26]>> What's the leg room looking like?

[00:04:28]>> I feel like we could build like a little foot platform, but it I'm totally comfortable. Is your knees hitting the fan?

[00:04:35]>> No. Pretty far away. I have lots of room. How does it look with someone in it?

[00:04:40]>> It looks sick.

[00:04:42]>> And with the seat up a little higher like this, we don't have to worry about not being able to see because we're higher than we thought we were going to be. So, I can see good. Now that we have our seating figured out, we are one step closer to driving this thing. But we have a major problem. Check this out.

[00:05:03]Oh no, that is just not going to do. Now Taylor's right. We can't have our wheels flying everywhere on a crazy adventure.

[00:05:10]So to fix that, we're going to be installing this very crusty steering rack that we've had in the shop for a while. This is from the frog cart, but we're done with that project. So we're going to be donating it to the little truck. Now, I've been thinking about this for a while. I think the best spot for this steering rack is going to be way down here under the motor. It's quite a squeeze, but I think it's gonna sit somewhere around there. Now, thankfully, because we've worked with this steering box before, we've already welded mounts to it, which is half the battle. But now, we need to take these mounts and give them something to bolt to. So, what I'm thinking we're going to do is we're going to take another piece of steel, notch it, and cross it from this bar to this bar. Then we'll weld it and then put some riv nuts in it and then this will bolt to that and then you'll be able to remove it if it needs to be serviced. And what I really like about this is it angles our output up towards the driver. If this had to be in front of the diff, we'd have to do something diabolical like chain steering or something crazy. I don't want to do that. I want to keep this as simple as possible.

[00:06:30]Oh, well, it'll hammer on.

[00:06:38]>> Dang, man.

[00:06:41]>> Playing some beats.

[00:06:47]>> All right, we've got our mounting bar.

[00:06:48]We also have riv nuts installed. And if you guys don't know what a riv nut is, it's this really cool little thing that uses this gun. I've linked this down in the description before, but I'll link it again. If you look that really closely, it does that inside the pipe. So, it secures these in there. And then you have threads in your metal that we can just bolt an M M8125 bolt into and this will mount right up. Our steering box is in, and it's moving. It's doing what it needs to do. Now we just got to take these tie rods and connect this to the wheels and see if everything works.

[00:07:30]Okay. Is this going to work out or no?

[00:07:33]>> I don't know. Time to find out.

[00:07:35]>> I'm a little nervous. I am a little curious. Look at the positioning of our tie rod. What do you guys think? I know someone in the comments is like a tie rod expert. So, if that's like totally wrong, let us know. We're still going to try it, but it might be a problem. I don't know.

[00:07:52]>> I feel like it's going to work. Which way are you going to turn so that we know?

[00:07:56]>> I'm going to turn this way. Hopefully, it doesn't go that way.

[00:07:58]>> Yeah, exactly.

[00:08:00]>> Oh. Oh my gosh.

[00:08:02]>> All right. Oh my gosh.

[00:08:06]Yo, >> that's pretty good.

[00:08:09]>> That's awesome. Check out the suspension, dude. finally get to see with the forlink. It really works.

[00:08:15]>> It really works. We're on the jack. Look at that thing move.

[00:08:19]>> That is pretty sweet. But for this steering to have a steering wheel up by the driver, I think we're going to work backwards. It seems counterintuitive, but I think this is the way that's actually going to allow us to position this where I want it to be. Now that our steering wheel is tacked up, we need to figure out the components that go from our wheels on the ground up to the steering wheel. So, the first thing that we need to tackle is this output coming from the gearbox. It's all wiggly and wobbly, and we just can't have that while we're driving. So, we need to figure out a way to secure this thing.

[00:08:50]And I think how we're going to do that is take some bars, if you look over here, basically just how we made the motor mount bars. And we'll do it right here, and take a bearing off of that and support this.

[00:09:07]Perfect.

[00:09:12]Okay, we've got our support welded in.

[00:09:13]And I also went ahead and built this bracket on the arch droid. Now, this bracket is going to bolt to our bearing.

[00:09:18]And our bearing is going to slide onto the steering shaft. And then we're going to take that whole system and weld it to our support bar. And then our steering shaft won't wiggle all about and it will be rolling on a bearing, which is going to be really nice.

[00:09:36]Now that we've got our steering shaft stabilized, we've got one more piece of this puzzle, and that is the connection between this and the steering wheel. So, I scounded around the shop a little bit, found this rod with some joints on it, and it also came with this weird spline thing that is going to make this whole system removable. So, we're going to take this section, weld it onto there, and then we're going to shorten this bar up a bit, and this piece will connect to the steering wheel. And then our steering will be done. Now, even though this is the smallest linkage, it's the most important because it connects our steering wheel to our front wheels. And any problem here is going to correlate directly into our steering. And if this system breaks, we're going to be left in the middle of nowhere with no way home.

[00:10:23]So, I'm spending a little extra time to make sure that it's serviceable and super strong. Everything's welded up.

[00:10:29]Let's see if this thing steers. Dude, I think this is going to steer really well.

[00:10:34]>> I mean, it's a pretty simple system, so it should.

[00:10:37]>> Are you ready?

[00:10:38]>> Give it a go.

[00:10:41]>> Hey.

[00:10:42]>> Oh, dude, that worked so good. Now that our front wheels aren't wiggling all over the place, we can actually work on some fun stuff. And the first thing that I want to address is this electric front-wheel drive system that's part of our four-wheel drive system. And we've never designed anything like this. And unintentionally, I think we may have just left just enough space for all of our electronic components to fit. Look at this. The battery fits right under the engine, right next to the CVT. It actually looks like a really good location. We've just got to hop on the computer and figure out a mount for this thing. Okay, so I was thinking of doing something fancy with this mount, but I realized if you look at this space, it really just needs to be a square. So, that's what we made. I tried to get a little fancy with it. Added some fillets so the corners are rounded, but other than that, we just need to cut this plate out. And I also made it long enough so that we can fit the controller in because we also have space for the controller. I can't believe it. I wasn't even thinking about this when we made it, but it just worked out. We have enough space.

[00:11:56]Wrong one.

[00:12:00]Bombs away.

[00:12:13]Well, yeah, that's a square. That's going to work great. So, here's the plan. We've got our square. We've got our battery. Battery is going to sit something like this with this that came off of the Lego cart.

[00:12:28]If you guys haven't watched that video, you probably should. It's very funny.

[00:12:32]But, this is going to go on top of there like that. Some bolts go through the holes and then we'll have our little ECU, ECM, whatever this is called. And it will sit right there and mount up with some riv nuts. So then we'll take this whole assembly and weld it onto the cart.

[00:13:00]All right, check this out. I'm super happy with how this whole system turned out. We've got the battery right here.

[00:13:05]If you look down here, we've got a bit of a rat's nest, but everything's soldered together and plugged in. This thing should start right up, dude.

[00:13:13]>> Start right up.

[00:13:14]>> Electric.

[00:13:15]>> Power right up.

[00:13:16]>> That's right.

[00:13:17]>> Are you ready?

[00:13:18]>> Yeah. Plug it in.

[00:13:20]>> We've got the beep of success. So, we don't have the proper hubs on the back.

[00:13:25]It's going to add a whole bunch of rolling resistance, but if this motor can push this whole thing with that rolling resistance, that means we've got plenty of power. Should we just try it out?

[00:13:35]>> Yeah. I'm going to back up, though.

[00:13:37]>> Ready?

[00:13:37]>> I'm ready.

[00:13:40]OH, >> NICE, >> BRO. Completely silent frontwheel drive that works. That's awesome. Now that we've got our front end figured out, there's one last thing that I want to do before getting this 670 V twin running, and that's our brakes. We always leave them for last, and it puts us in situations like this.

[00:14:05]The brake does not work at all, guys.

[00:14:08]Now, believe it or not, most of the hard work's already been done for us because this custom axle has brake mounts and brake rotors. We also have these brake calipers that came from Go Powersports, and they fit up. Now, while you're sitting in this machine, if you look down here, there's not much room for your feet. So, what I'm thinking we're going to do is use this motorcycle front brake and put it right here. This is well within the body and super easy to grab. It's also going to be a really easy system to set up. These things actually look pretty good, dude.

[00:14:40]>> Yeah, they look sick.

[00:14:42]>> We've never had two brake calipers on a machine before.

[00:14:46]>> That's actually insane, too.

[00:14:48]>> If you think about it, we always just have one. And I think that's our problem. So, now we have redundancy. We also have double the braking power. But you might notice we have two lines and one master cylinder. So, what we're going to do is we're going to take this three-way splitter, bolt it up under the seat, run these two lines to the splitter, and then run a line off of that to our master cylinder. Our brakes are connected up, and supposedly they're bled, but we need to see if they actually work because usually we have some serious problems. Hey, Katie, are you done painting that turbo?

[00:15:21]>> Uh, yeah.

[00:15:22]>> You want to come over here and spin this thing? We've got a bit of a guest appearance on the show today.

[00:15:27]>> Okay, I'll spin it. All right. Spin it like we're going really really fast.

[00:15:32]>> WELL, >> try really hard. Try >> try really hard.

[00:15:38]>> Now, really try >> try.

[00:15:41]>> I'd say that's going to do.

[00:15:42]>> It looks like Shrek's ears.

[00:15:44]>> Um, I'm an artist and so is Shrek, so I kind of replicated him in my turbo.

[00:15:51]>> He's my inspiration.

[00:15:53]>> It looks pretty nice.

[00:15:54]>> Thank you. Now that we have the brakes settled, it's time to focus on our big bad 670. And as you can tell right now, this thing's going to be pretty loud. We don't want it to be that obnoxious. We do have the stock exhaust, but this thing's pretty heavy and honestly really ugly. So, what we're going to do is we're going to cut these connectors off of this. And then we have this bag full of all this nice pipe of different turns and everything. We'll make our own custom exhaust and it'll be nice and sleek.

[00:16:32]>> That made a kind of funny noise.

[00:16:34]>> It sounded like a digery do.

[00:16:40]>> All right, Taylor went ahead and got these little nubbins cut off the exhaust and cleaned up. And now we can take these little nubbins and bolt them to our engine.

[00:16:50]And that will give us a great spot to start planning out this exhaust because it's going to be quite complicated.

[00:16:56]There's going to be a ton of bends and I want it to look really nice. So, we're going to take our time.

[00:17:11]We've got an exhaust that looks pretty nice, dude.

[00:17:15]>> I like it.

[00:17:16]>> It looks interesting. It's got a couple bends in it and it's stainless so it shouldn't rust. Well, the welds aren't stainless so they'll rust. But the rest of the pipe's going to look really nice.

[00:17:26]So, it bends down here and I'm thinking for this exhaust, I don't want to go all the way to the back. That's a ton of material and I just don't think it's going to look as cool as if we come out the side of the car. So, we're going to have this exhaust end that our friend Frank gave us. I don't know what it goes to, but it looks perfect. Perfectly small, perfectly cool. And it's going to sit something like that. Come out the body right here. Side exit. Very steey.

[00:17:54]We've got some STE points for this one, I think. And then we'll just figure out how to get the pipe to go from here to the entrance of this exhaust and be done.

[00:18:15]Our exhaust is done. And look at this thing.

[00:18:19]Dude, >> that looks really professional.

[00:18:22]>> It does. Right now, this exhaust looks like it's sticking way far out, but once the body goes on, I think it's going to look really sweet. So, let's get that body on here, cut the hole, and see what this whole thing looks like.

[00:18:39]Perfect. Perfect. Okay. Yeah, that's going to work great, dude.

[00:18:57]Oh, dude. It's perfect.

[00:19:00]Last night, we designed this super sick exhaust. I mean, just look at it. Comes out the body of the car, and I think it's going to sound mean. But before we can hear this engine start up, we've got to figure out one more thing, and that is our gas tank. Now, this is the gas tank we're going to use. It's the perfect size and it's got a great mounting location right around here so that when the body goes on, it's going to be completely hidden. We're just going to have to design a couple of mounts that weld to the tank and hold it to this tube work. All right, we've got our mounts cut out. And in the past, we'd probably just weld this tank on, but I made these ones removable, so they'll bolt to the frame and that way our tank can come off. I don't know if it will ever need to come off, but it's a nice little feature. So, we've got three of them. And I think that's going to be plenty. One sits right there. One sits right there. And one goes right there. What do you think?

[00:19:51]>> Looks good.

[00:19:52]>> I think it's going to work.

[00:19:55]>> Wo.

[00:19:58]>> Okay. Yeah, it did. It >> glad I did that. Holy cow. That would have sucked to be welding and have your face right here. Is it going to do it again?

[00:20:09]>> Wow.

[00:20:10]>> Wa. Yeah, there was a lot of fuel in there.

[00:20:26]Wow, that's really satisfying. Now that we've got our gas tank bolted up, everything should be done. We've got fuel line running from the tank to the engine, and I'm a little concerned that there's not going to be enough pressure at the mechanical pump. So, I added in this little primer bulb, which you can press while you're sitting in here. It's going to be really nice. I also went through and finished up a couple of things that I didn't really think was worth filming, like this foot pan. If you remember before, your feet were just kind of sitting there with nowhere to go, and I was a little worried that they'd get wrapped up in the drive shaft. So, now that's good. I also simplified the 670s switch panel cuz this thing is advanced and it's large.

[00:21:08]It sat right up at the front of the engine and I just didn't like the way it looked. So, I built this little key thing right here. I think it's pretty nice. It's right up next to the driver.

[00:21:18]It's way simpler than this and I think it's going to work really great. But is there anything we're forget, dude?

[00:21:25]>> Uh, I don't think so.

[00:21:26]>> Besides getting the body on here and taking it for a test drive. Let's go.

[00:21:30]We've got the truck outside just in time. It's about to get dark, but I have to see how this thing works because Taylor and I have spent multiple weeks building probably the most complicated project ever on bomb. Are you ready, dude?

[00:21:45]>> I am very ready.

[00:21:47]>> We've got fuel. What if it just takes off when I turn it on?

[00:21:52]>> Well, then just turn it off if that happens.

[00:21:54]>> Yeah, I guess I've got the switch panel really close. All right, fuel is primed up to here. If I turn this switch, we should be good to go.

[00:22:04]>> Okay.

[00:22:04]>> Ready?

[00:22:05]>> Yeah.

[00:22:12]>> Oh, choke. Maybe.

[00:22:13]>> Maybe.

[00:22:17]>> Oh.

[00:22:17]>> Oh, >> she's about to go. I'm so excited to see what that exhaust sounds like.

[00:22:23]>> Yeah, dudes.

[00:22:24]>> Ready?

[00:22:31]OH YEAH, BROTHER.

[00:22:33]>> That sounds pretty good.

[00:22:35]>> Oh, it wants to go. Should I just give it a go?

[00:22:40]>> Let it warm up.

[00:22:41]>> Okay, we'll let it warm up a little bit.

[00:22:43]Dude, this feels proper. We don't have a air filter on the top, so all the fuel kind of busts out of here into your face, but other than that, >> dude, this sounds really good.

[00:22:55]>> I'm really happy with the exhaust. that >> I was thinking it was going to be louder than that, BUT THAT SOUNDS PROPER. AND I'M MOVING.

[00:23:03]Holy Wait.

[00:23:06]Yeah.

[00:23:07]>> Look at this. Check that out.

[00:23:11]>> Wow, dude. Do it again.

[00:23:15]>> Okay, that is so cool.

[00:23:18]>> That's holding together.

[00:23:19]>> It is.

[00:23:20]>> Okay.

[00:23:22]>> Yeah.

[00:23:22]>> Let's see. It should be warmed up.

[00:23:24]>> Give it a trundle.

[00:23:25]>> Okay. Ready? Wait. Brake. Good. Yeah.

[00:23:28]All right.

[00:23:28]>> I think the brakes Yep. The brakes working. I'm going to go around the block.

[00:23:33]>> All right.

[00:23:36]>> Oh, wow.

[00:23:44]For a first drive, that thing seems to work really good. There's no way we managed to pull this off.

[00:24:01]I can't believe it. That is the best situation I could ask for. This thing feels locked in. It's like spending some time on a project for once actually paid off. Let's see if the brakes work. Yes.

[00:24:19]Oh my gosh. Yes. Thank gosh.

[00:24:23]Oh, we've got some crazy camber going on.

[00:24:40]>> Oh.

[00:24:40]>> Oh no.

[00:24:43]>> Oh no. What happened?

[00:24:46]>> Um, yeah. So, something is not right with the steering.

[00:24:50]>> Oh man. What in the heck is that, bro?

[00:24:55]Before that happened, it was driving nice. I think we might have some problem going on with our suspension. I wonder if the regen on the electric motor in the frontwheel drive system is like locking up because once you get going pretty fast, >> it like starts vibrating the front diff.

[00:25:15]>> Well, that's not good. hard like but bro that is so cool. I never want to use a chain driven system ever again. Having proper rear end on this thing makes it so enjoyable. It does the squat when you give it power.

[00:25:31]>> It does.

[00:25:33]>> Yes, >> man. We've just got to figure out what's going on here. All right. So, here's what's going on. It's a very interesting problem. And I kind of didn't even think this was a problem we were going to run into. Our wheel bearing, our Amazon wheel bearing total itself. Dude, >> you didn't think about an Amazon wheel bearing maybe failing?

[00:25:56]>> I thought these would at least hold up for a little longer than that. And I think it failed for a very specific reason. There's something going on between the experimental electric four-wheel drive, our weird suspension, and the very improper steering.

[00:26:12]Yeah, something isn't working right. So, this thing naturally wants to tow out when the suspension compresses. And because we have a 670 up front, it always compresses when you decelerate.

[00:26:24]And that's when this happened. I was giving it a little gumption. This is a test drive, so I really wasn't going very hard. And I let off the throttle, compress the suspension, towed out, and then towed out way too much. broke the bearing, jammed up our wheel, and destroyed a whole bunch of stuff.

[00:26:44]>> Ah, there we go.

[00:26:47]Okay. All right.

[00:26:48]>> Ah, a little piece of our bearing just popped out, >> dude. It is mangled.

[00:26:55]>> Oh my gosh.

[00:26:58]Holy cow. What the heck? Good thing I didn't keep driving it. It would completely mangle up our hub, man. Maybe we rushed the first drive.

[00:27:08]>> Maybe.

[00:27:09]>> Possibly. I thought this was going to go a little bit better. It sounds awesome.

[00:27:13]Everything we built works except for the front suspension. I think that's our problem.

[00:27:18]>> Yeah, I guess so.

[00:27:19]>> Something's going on here that's fishy.

[00:27:22]Froggy, some would say.

[00:27:26]And this is why you make all your components serviceable. Taylor, >> that's a good point. You're asking why everything needs to be removable. It's cuz if we're on a trail in the middle of nowhere, we're going to have to be able to remove all of this stuff. Oh my gosh.

[00:27:43]I can't believe the damage, honestly.

[00:27:49]Oh, there's our wheel bearing. Wow, look at that.

[00:27:53]>> Gone. Where'd it go?

[00:27:57]>> That's all right.

[00:27:57]>> Got a couple loose bolts. Not a proper project if it doesn't have a couple loose bolts. Well guys, we have a problem. I took apart this hub a little more and it turns out both of our bearings are destroyed. This is what's left of them. And we only have one bearing in the shop that could fix this.

[00:28:15]So, unfortunately, that's where we're going to have to end this. I wanted Taylor to get a drive it, and I'm sure he will be able to in true will fashion.

[00:28:25]I destroyed the machine before you could test it out, bro.

[00:28:28]>> Well, it's not the first time it's happened.

[00:28:30]>> I'm honestly so disappointed. I thought that the frontwheel drive system was going to work a little bit better, but it honestly needs quite a bit of work to function correctly. Now, let's take a look at this suspension.

[00:28:43]Take a really good look at this suspension and let me know with all of your guys' brains. What's going on here?

[00:28:51]Why do we get this weird toe out? Or was that just the Amazon wheel bearing? Cuz I really don't know. I'm at a stump. I think we did everything right. But the only thing I do think might be a problem is this steering angle or maybe the electric four-wheel drive. I don't know.

[00:29:09]But that's it for this video. I'm very happy with this machine. For three weeks of work, we've got a fully custom frame, miniature four-link suspension, a front-wheel drive system that's electric and kind of works, and a truck that looks super sweet. Also, an exhaust that I am blown away with. So, if you like this kind of content, make sure to subscribe. We post every single Sunday, and we'll see you next time.

[00:29:40]Yep. That's 10:30 for sure.