The Honda CT70 is looking beautiful after its Redline Rebuild treatment and, of course, it’s running like a top. Davin is not one to keep secrets about the work that’s been done and what challenges arose along the way. There were  plenty of updates along the way, but sometimes the best time to talk particulars is when looking at it reflectively. So Davin and lead videographer Ben sat down to talk through the nuts and bolts of this big little project.

First, Davin explains why he chose a Trail 70. “We’d been getting messages about doing something other than an engine for awhile, and motorcycles always rose to the top of the conversation. Between my personal experience with the Trail 70 and its nearly legendary status with enthusiasts, it was the perfect choice.” Of course, when it came time to pick up a restoration candidate, Davin fell back on an old maxim: Purchase the best example you can find to restore. In this case it meant a running and riding bike.

“That machine was pretty tired though. Complete, but tired.” That often makes things a lot easier for a restoration. Documenting how parts fit together during disassembly is a lot easier when they’re all there. Also it can make better financial sense to buy something with parts that can be restored rather than swiping the credit card for each missing piece. Davin guesstimates there are about as many parts into the entire Trail 70 than a single V-8 engine, which means this project might look fairly simple, but it  can also be deceptively complex—mainly to keep organized once it’s all apart.

In that blown apart phase it was all about cleaning and acquiring parts. Luckily, Davin had the experts at Trail Buddy on call to help find and advise on just what he needed. They also helped rebuild the front forks and sprayed the tri-stage candy paint, a paint that surprised Davin both then and now. “It really blows me away that Honda would have done such a complicated paint process on what amounts to a kids bike. These were often used and abused, and that paint makes touch ups really difficult.” No matter when he was re-spraying the entire frame.

Then it came down to assembly, which is where this man thrives. Between Davin’s trusty shop manual and the guys at Trail Buddy, the bike slipped together quite quickly. Now it’s ready for some off road adventures—right after someone puts the first scratch in that beautiful paint. Davin is still a bit squeamish, but he knows that after that first ding, all bets are off. This bike was made to have fun, and that’s what it’s going to do.

To keep track of this and other projects in the Redline Garage, be sure to subscribe to the Hagerty YouTube channel. — Kyle Smith

Thanks to our sponsor RockAuto.com, an auto parts retailer founded in 1999 by automotive engineers with two goals: Liberate information hidden behind the auto parts store counter (by listing all available parts, not just what one store stocks or one counter-person knows), and make auto parts affordable so vehicles of all ages can be kept reliable and fun to drive. Visit RockAuto.com to order auto parts online 24 hours a day, 7 days a week, and have them conveniently delivered to your door. Need help finding parts or placing an order? Visit the Help pages for further assistance.

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Davin and the crew in the Redline Rebuild garage love a giant project, but they love a tiny one, too. Especially since even their small-scale projects are pretty involved. The latest full rebuild to begin is also the first to be finished. That’s right, the 1973 Honda CT70 is done. Might have something to do with the number of parts … Or maybe the fact that Davin used his phone as much as he did the wrenches.

The CT70 is better known at the Trail 70 and served as a literal and figurative jumping-off point for the lifelong passion of many gearheads. Honda introduced the little trail machine in 1969 and produced it until 1981 without changing much. With a lay-down, single-cylinder four-stroke engine, the CT70 is easy to maintain and has enough power to scoot around most adults, although with slightly less vigor that it would a lightweight kid. The easy-to-use, clutchless three-speed gearbox most models featured meant that just about anyone could operate one—and get hooked on the fun of two wheels.

Davin enjoys a motorcycle ride as much as the next guy, but the shop is his happy place. He didn’t hesitate for a second when this bright orange model popped up for sale in the Traverse City, Michigan, area. It was more than a little tired, but the pint-sized bike was complete. “It was really a perfect restoration candidate,” Davin says, sitting atop the finished bike in the Redline Garage. “Everything was there, and it hadn’t been cut up or really abused.”

That made for a quick teardown that left only the bare stamped-steel frame on the workbench. Davin then realized this machine was a little bit outside his normal piston-powered projects. Out came the phone and soon on the other end of the line was Trail Buddy Inc in Zeeland, Michigan. The crew there served as the expert resource for Davin throughout the Trail 70 restoration process. In fact, it was Trail Buddy that helped rebuild the front forks and sprayed the frame with three-stage orange-candy paint.

The 700cc thumper was all Davin, though. “A little engine like this is great for beginners to learn, and really fun for experienced folks, too. There aren’t a lot of parts but they all work just the same as they would in a bigger and more complicated engine,” says Davin. Add in that most, if not all, parts you will need for a rebuild are available and fairly affordable, and you have a great project candidate.

The paint was not the only item for which Davin called in the experts. From the final cam-chain tension adjustment to his dad stopping in to re-cover the seat, this project evolved into a serious group effort. Davin admits the process was more involved than he expected, but he’s still adamant about telling folks to undertake similar projects themselves. “There is nothing wrong with phoning the experts or reaching out in-person to someone who knows more than you do. No one knows everything, and the friends you will make in those conversations can last a lifetime.”

With any luck, this Honda CT70 will last just as long. Where will Davin take this little adventure-ready bike? We don’t even know, but if you want to find out, and discover what is next for the other projects in the Redline Rebuild garage, subscribe to the Hagerty Youtube channel and wait for the weekly updates like the rest of us. We promise it’ll be worth the wait. — Kyle Smith

Thanks to our sponsor RockAuto.com, an auto parts retailer founded in 1999 by automotive engineers with two goals: Liberate information hidden behind the auto parts store counter (by listing all available parts, not just what one store stocks or one counter-person knows), and make auto parts affordable so vehicles of all ages can be kept reliable and fun to drive. Visit RockAuto.com to order auto parts online 24 hours a day, 7 days a week, and have them conveniently delivered to your door. Need help finding parts or placing an order? Visit the Help pages for further assistance.

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As slow as the CT70 will be once it’s done, it is sure coming together fast. Davin is making big strides to tidy up the little machine and ready it for its first outing. Between here and there are some hurdles though, and they have the Redline Rebuild master calling for a little help.

The front end of the bike, which was pre-assembled a few weeks ago, slid right into the steering neck of the stamped steel frame, and a burette that’s normally used to cc combustion chambers in the engine room got repurposed to put just the right 3.5-ounce oil into the fork legs. It’s probably a little bit of overkill on the accuracy, but Davin is not one to ballpark something he can measure perfectly. That might be why he struggled with the second task of the day.

The cam chain has a hydraulic tensioner, but it still needs a base setting. The manual was no help as it says to set the tension with the bike running. Davin doesn’t want to risk damage by starting the engine and then adding tension. That could lead to the chain skipping a tooth and causing valve-to-piston contact. So Davin dialed up Trail Buddy to get get a professional opinion. A quick conversation got the base setting dialed so the engine should be all but ready to start.

Before that first fire up though, the bike needs a seat. It’s been looking awfully naked this entire time, and though upholstery can be an approachable first project, it is Davin’s dad who comes to his rescue this time to make the CT70 seat better than when it rolled out of the factory. A new cover, foam, recondition trim and base all combine to become one very tidy and pretty package when assembled by skilled hands.

Speaking of skilled hands, the engine was assembled by Davin, and that’s why the spark plug fires a strong and bright spark when he turns the kickstarter by hand. Only finishing touches are left, but you won’t get to see this one again until it’s all done and running. We promise it will be worth the wait. Be sure to subscribe to the Hagerty YouTube channel to get notifications with each video that goes up—including the full timelapse of this restoration.

Thanks to our sponsor RockAuto.com, an auto parts retailer founded in 1999 by automotive engineers with two goals: Liberate information hidden behind the auto parts store counter (by listing all available parts, not just what one store stocks or one counter-person knows), and make auto parts affordable so vehicles of all ages can be kept reliable and fun to drive. Visit https://www.rockauto.com/?a=HG-YT-21Q3 to order auto parts online 24 hours a day, 7 days a week, and have them conveniently delivered to your door. Need help finding parts or placing an order? Visit our Help pages for further assistance.

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The orange Trail 70 has been a real fancy workbench decoration for the last six months. All the new and refinished parts have been sparkling from their perfectly organized places in a corner of the Redline Rebuild garage. Now final assembly is underway, and the bike’s current is a unicycle. Davin thinks he could still ride it. We think he shouldn’t try.

Assembling the Trail 70 gives a real lesson in the thrift and cleverness that the Honda designers had back in the late 1960s. There are plenty of 10mm bolts clamping things together, but the gas tank is an example of effective cost cutting. Rather than clamping it in place, there are a few small rubber isolators that effectively wedge the tank inside the stamped-steel frame. A small top plate keeps it all snugly in place. Simple, relatively fail-proof, and easy to assemble.

The rest of the rear end is similar but has a few more fasteners. The swingarm bolts into place followed by the rear wheel, shocks, and brake pedal assembly. For once, things are sliding together easily. Could that continue through the rest of the Trial 70 assembly and first start? Maybe, but you’ll have to tune in to future episodes to find out. Be sure to subscribe to the Hagerty YouTube channel to never miss an update.

Thanks to our sponsor RockAuto.com, an auto parts retailer founded in 1999 by automotive engineers with two goals: Liberate information hidden behind the auto parts store counter (by listing all available parts, not just what one store stocks or one counter-person knows), and make auto parts affordable so vehicles of all ages can be kept reliable and fun to drive.

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This week Davin takes himself back to high-school chemistry class as we attempt to tackle zinc electroplating. Requiring only a few materials from the hardware store, this seems like a pretty straightforward process, but projects are never as simple as they first appear. This week’s video is less of a “how-to” and more of a “show and tell us what we can do better.” So, hit up those comments on Youtube and let us know how we can improve our process.

Thanks to our sponsor RockAuto.com. RockAuto.com is an auto parts retailer founded in 1999 by automotive engineers with two goals: Liberate information hidden behind the auto parts store counter (by listing all available parts, not just what one store stocks or one counter-person knows), and make auto parts affordable so vehicles of all ages can be kept reliable and fun to drive. Visit https://www.RockAuto.com to order auto parts online 24 hours a day, 7 days a week, and have them conveniently delivered to your door. Need help finding parts or placing an order? Visit our Help pages for further assistance!

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The small scale of the Honda Trail 70 means updates and progress happen fast. For example, Davin took a trip to the machine shop to get the precision bits cut to size and ready for assembly. Then he couldn’t help but go ahead and put it all together too.

The cylinder was the first thing to get mounted into the machines at Thirlby Automotive. A quick pass with one of the smallest boring bars in the shop brought the bore not only to properly round, but also to the size appropriate for the new piston. Final size was set with the hone to make everything just perfect. From there the attention shifted to the cylinder head.

The valve seats and corresponding valves were not in the worst shape, so the team decided to cut the valves and give a quick grind to the seats. This created fresh sealing surfaces to make sure the small valves won’t leak. It’s a simple process that requires a careful hand when dealing with parts this minute. The team at Thirlby provided that steady hand, and the finished product was soon ready to head back to the Redline Garage for final assembly.

That assembly went fast, but it was important not to miss any of the precision checks in the flurry of assembly excitement. Take the piston ring end gap, for example. The shop manual laid out the specs, and Davin got lucky that the new rings were perfectly in the middle of the range that was called for. Some oil and the cylinder slid down over the piston, followed by the cylinder head and valvetrain.

A couple of final touches and the engine was complete. It’s now ready to be slipped back into the chassis. If you want to see that, you’ll have to tune into a future Redline Update. Make sure you never miss an update by subscribing to the Hagerty YouTube channel.

Thanks to our sponsor RockAuto.com. RockAuto.com is an auto parts retailer founded in 1999 by automotive engineers with two goals: Liberate information hidden behind the auto parts store counter (by listing all available parts, not just what one store stocks or one counter-person knows), and make auto parts affordable so vehicles of all ages can be kept reliable and fun to drive. Visit RockAuto.com to order auto parts online 24 hours a day, 7 days a week, and have them conveniently delivered to your door. Need help finding parts or placing an order? Visit Rock Auto’s Help pages for further assistance.

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It should come as no shock that Davin has little resistance to a bit of wire-crossing. The Honda Trail 70 restoration proves that. The engine is on its way back together, which means that the charging system needs a bit of love before things can get finalized. Luckily, it’s only a few tools and a dab of solder to have this stator ready charge.

The stator of a motorcycle is akin to the alternator of an automobile. Because motorcycle engines tend to be compact, the stator gets tucked inside the case rather than bolted on the outside. Like its bigger, automotive relative, a motorcycle’s stator is comprised of just a few parts: copper windings, a large magnet, and the wiring to direct the created current. The Trail 70’s stator was actually in acceptable shape when the bike arrived on Davin’s workbench, but that is not good enough for the Redline Rebuild expert.

A couple screws and a dab of solder to make the final connection, and the Trail 70 is ready to charge again. Assembly continues next week and if you don’t want to miss an update, be sure to subscribe to the Hagerty YouTube channel.

Thanks to our sponsor RockAuto.com. RockAuto.com is an auto parts retailer founded in 1999 by automotive engineers with two goals: Liberate information hidden behind the auto parts store counter (by listing all available parts, not just what one store stocks or one counter-person knows), and make auto parts affordable so vehicles of all ages can be kept reliable and fun to drive. Visit RockAuto.com to order auto parts online 24 hours a day, 7 days a week, and have them conveniently delivered to your door. Need help finding parts or placing an order? Visit our Help pages for further assistance!

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The traditional Redline Rebuild is was just an engine, but in the case of the Honda Trail 70, Davin is working on the motor as just one part of a bigger machine. The engine on these small bikes goes together fast enough at normal speed that the time-lapse concept is almost overkill. Think we’re joking? This week’s Redline Update proves it.

Before assembly can happen, the cleaning must happen. It’s often an off-camera job simply because it is the most boring part of any project. It might be an uninteresting process, but the results are often worth the effort. For the Trail 70, Davin tried vapor honing, a technique he had not yet used on a Redline Rebuild project. The engine case was shipped down to Ohio, where a friend spent a half hour blasting away years of grime and corrosion. The finished product is gleaming and ready for the roller bearings to be pressed in.

Once a few bearings are in place, the assembly goes quickly. Since the Honda is mainly press-fit roller bearings, there is minimal measuring like the automotive engines Davin is used to. The simple transmission tucks in nicely before the crankshaft settles in next to it. The clutch plates soak in oil for a lunch break before going together to wrap up this assembly session.

Next up is the piston and top-end assembly, and if you don’t want to miss a minute of the process be sure to subscribe to the Hagerty YouTube channel to get notifications when each video goes live.

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Like many of us, Davin often finds that progress on his many project cars gets delayed. This week, he’s hung up with the ’37 Ford dirt-track racer—and, for once, that’s a good thing, because it’s time to build the Ford’s rear suspension.

Davin customized the leaf springs a few episodes back and now they are mocked up in the car. There is a second part to the suspension puzzle, though: The shocks, which keep the springs from bouncing wildly and thus help with chassis stability and traction. Two very important things in a race car.

Davin could simply bolt on the shocks between the axle and chassis and let “good enough” suffice, but we all know he isn’t that kind of guy. Instead, he takes the time to locate the shocks at the proper angle and distance, trusting that the additional time will pay off in the final build. For dirt-track cars like this one, the suspension is intentionally uneven in an effort to keep all the wheels in contact with the ground. The driver’s rear tire needs to droop while the passenger rear needs more compression, and the shock location and setup need to reflect that attitude. Davin makes the process look easy by fabricating a couple quick mounts that allow him to get all the components located easily.

After realizing he lacks the raw material to fabricate the final bits of the Ford’s shock mounts, Davin takes the delay as an opportunity to grab some parts for the Honda Mini Trail and head to the body shop. The frame is completely sandblasted, but that doesn’t that mean the Honda’s ready for paint.

The crew at Traverse Body and Paint make quick work of removing the one small dent in the pressed sheetmetal, and then add a quick glaze-coat of filler to smooth out any sanding marks or small imperfections. So many people hear “filler” and pucker up, imagining giant chunks of Bondo falling out of quarter panels, but that’s not what is going on here. In fact, the glaze-coat that Dave puts on this Honda is sprayed on and, once dry, mostly sanded off. Its sole purpose is to smooth out sanding marks and other minuscule imperfections. The final coats of color will be done by the experts at Trail Buddy in the coming weeks.

Stay updated on these two projects and many more to come by subscribing to the Hagerty YouTube channel. We promise there are some projects on the horizon you won’t want to miss.

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Probably the smallest project on Davin’s 2021 roster is this orange Honda Trail 70. It’s a running and riding bike, but it’s far from perfect and could use some love. Teardown time for the air-cooled single-cylinder moves quickly, so let’s get to it.

The Trail 70, or CT 70 as it is also known, came stateside in 1969. It was the perfect bike to get those curious about motorcycles absolutely hooked on riding. The diminutive size made it approachable and comfortable for just about anybody, and the peppy four-stroke, single-cylinder engine was both quick and easy to handle, especially with the three-speed transmission behind it. The Trail 70 is a machine that bike people often say “gives room to grow,” meaning that it’s forgiving enough to learn on, but remains entertaining and rewarding as the rider gains experience.

The orange model Davin is going after looks to be in pretty good shape at first glance, but with each step of disassembly this little machine delivers some piece of hidden bad news. Luckily, none of the items found are catastrophic and each can be easily rectified. Before those fixes can take place, however, everything is going to need a good bath and scrub-down.

That’s for next episode, though. For now, go forth and heed Davin’s call to go work on your projects. And if you don’t want to miss the next Redline Update, subscribe to Hagerty on YouTube.

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