Project 1970 Honda CB350 — Part III

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by Richard Backus
Our project Honda CB350's finished frame.

The is the third in a series on our 1970 Honda CB350 build project. Read Part I and Part II for earlier stages of the project, and Part IV, Part V, Part VI, Part VII and Part VIII for the later installments. You can also watch video of our Honda running for the first time.

We’ve been pretty satisfied with the rate of progress on our project 1970 Honda CB350. It hasn’t been too hard squeezing the tear-down work in between our “real” work, and things were going really well until — you knew this was coming — we got hit by the unexpected: And it wasn’t a problem with the bike.

The unexpected problem had nothing to do with our CB350, although, somewhat ironically, it did involve a Honda; just not this one. A few weeks after shipping the last issue, I was kickstarting my 1966 Honda CA95 when the kickstarter stopped, but my leg kept going. The resulting torn Achilles’ tendon, followed by surgery, took me out of commission for a few weeks. I’m starting to get back up to speed, but the injury had a big impact on our progress. Tech Q & A man Keith Fellenstein, editor Landon Hall and myself have been knocking this out in our free time: Knock any one of us out and things slow down.

But it’s not all bad news, because we have managed to take care of a few important bits, some of them even with yours truly on crutches.

What’s happened

The most visible progress is the frame, which we carted off to Stuart Armstrong at Custom Coatings & Metal for media blasting and powder coating. As we’ve come to expect from Stuart, the frame, swingarm and various other metal bits we gave him came back looking so good, it’s hard to believe they’re the same parts we dropped off.

A major concern unearthed last issue was a broken engine mounting boss. We’re not sure how it happened, because there’s no frame or other damage around the mount like you’d expect if someone had hit something riding. We decided to see if it could be welded back up, so after letting the engine oil drain for several days (accompanied by heating up the block with a heat gun to encourage flow) we trucked it over to Bruce Silkey, who’s made an art of repairing broken Harley-Davidson and Indian engine cases, cylinders and heads.

From the outside, there’s nothing about The Pit Stop, Silkey’s country shop, to suggest anything special goes on here. There’s no sign, no motorcycles out front, it’s just another Butler building — until you walk in and see Harley and Indian engine bits in various stages of welding repair. A Shovelhead engine in a fresh frame sits on a cart on one side of the shop, the wall above it lined with dozens of Harley and Indian connecting rods, while the other wall is lined with lathes and other tools of the trade.

Silkey gave the engine his attention, explaining what he was doing as he cleaned the area around the broken mount before heating the case with a propane torch to burn out any contaminants and encourage the weld. Satisfied it was ready, he bent down and got to work, and 20 minutes later we loaded up our engine and carted it home for final dressing and cleanup. We didn’t ask for the level of detail — or time — Silkey gives his favored V-twins, but it came out great.

We also got our wheels disassembled so we can send the hubs off to Buchanan’s Spoke & Rim. Originally, we planned on having Buchanan’s lace up our hubs with new spokes and rims, but after talking to Robert Buchanan, we’re taking his advice and just having them respoked. Replica chrome rims are available, but Robert says it’s hard to match the quality of the Honda’s original D.I.D. rims. While not perfect, our rims are actually in fairly good shape. They’re straight with no dents, with only mild blemishing and some mild corrosion on the inside. A quick clean and they came up well, and thoroughly cleaning and coating the inside  where the tube sits with a coat of silver epoxy should keep any corrosion at bay. We still need to polish up the hubs, but once that’s done we’ll ship the hubs and rims off to Buchanan’s.

The control cables had all seen their best days, and a quick check with Barnett Clutches & Cables confirmed they could make up new ones for us — including the tachometer and speedometer cables with their unique mounting at the engine and wheel. We duly boxed them up and sent them off, and I’d almost forgotten about them until they came back, the day before we shipped this issue. We’ll show you photos of the new and old next issue, but the new cables from Barnett are predictably excellent, the front brake and clutch cables featuring nylon-coated wire and a lined, heavy-duty outer sheathing. They’re black, not gray like the originals, but that’s OK, because we never intended this to be a trailer queen. It’s going to be a rider, and these are perfect.

Barnett also shipped along a full set of clutch discs and springs. We haven’t gotten to that stage of the project yet, but it’s good to know we have the parts. We should know where the clutch stands by next issue, as we plan to pull off covers and get into the engine a bit as we clean it up. If we decide to paint any parts of the engine, friend of the magazine Tim O’Mahony sent us a can of VHT High Temperature Wheel Paint to test. He says it matches the original Cloud Silver beautifully; after painting the side covers on his wife Karen’s CB160, he had someone ask where he managed to find new-old-stock covers. We’ll let you know.

Next step

We still need to polish the hubs before we send them off to Buchanan’s, and there’s a lot of work to do as we get ready to start hanging parts off the frame. The front fork tubes need to be replaced, so we’re turning to Forking by Franks for a new set. New tubes from Franks (we’ve used their tubes on just about all our projects) will be guaranteed straight and smooth, and the quality can’t be beat. Naturally, we’ll overhaul the front forks while we’re at it. We’d originally planned on converting to tapered bearings for the steering head, but the stock races are in fine shape. Tapered bearings will take a much bigger load than the original ball bearings, but these aren’t such big bikes that it’s critical, so we may just get new ball bearings and call it good.

That leaves a myriad of details, including deciding on tires and finding a replacement seat base; ours looked OK until we removed the cover and discovered that it’s shot. We already have new foam and a new cover from Sirius Consolidated, but a replacement pan has proven elusive as the early pans (1968-1970) hinged at the rear instead of the side, as the later bikes do. But hope springs eternal, and one way or another, we know we’ll sort it out. And besides, it’s part of the fun. MC

Project Honda CB350 Suppliers

Barnett Clutches & Cables: New clutch, brake, speedometer, tachometer and throttle cables, new clutch discs and springs
Better Life Technology
: G-Floor vinyl shop flooring
Buchanan’s Spoke & Rim
: Relace wheels with new chrome spokes
Charlie’s Place
: Electronic ignition, ignition coils and mounts, voltage regulator/rectifier
Custom Coatings & Metal: Media blasting and powder coating
Dime City Cycles
: Tapered steering head bearing kit, miscellaneous hardware
Forking by Frank
: New fork tubes
Hagon Shocks USA
: Classic I chrome shocks
Sirius Consolidated: Master carb rebuild kit, seat foam, seat cover, seat strap and buckles
The Pit Stop: Aluminum engine welding — (785) 887-6626

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