Beating the Tariff: Brian's 1985 Honda CB700SC Nighthawk S

Brian's 1985 CB700SC Nighthawk S is taking up space in the shop right now. It is a clean survivor in the classic black-and-blue paint, but the machine has sat static for years. A mobile mechanic came through, took a look at it, and completely flaked on the job. Now it is sitting here for a massive recommissioning. Staring at this piece of iron every day is a good reminder of the political dogfight that forced Honda to build it in the first place.

Back in 1983, Harley-Davidson was getting absolutely crushed by cheaper, faster Japanese motorcycles. Instead of building a better machine, Harley lobbied the government. The Reagan administration bailed them out by slapping a massive 45% import tariff on any motorcycle over 700cc, deliberately designed to choke out the Japanese 750 market.

The Japanese did not roll over. They just did the math. Within a year, they sleeved and destroked their 750cc powerplants down to 696cc. They slid under the federal tax barrier by a fraction of a millimeter. But Honda didn't just shrink the motor on the CB700SC to save a buck; they engineered it to be an absolute anvil of a street brawler to prove a point.

First, they killed the worst part of owning an inline-four: the valve clearance check. Instead of forcing you to pull the cover every few thousand miles to swap shims, Honda engineered hydraulic valve lash adjusters. They are self-adjusting and silent. You close the top end and forget about it.

Next, they threw away the chain and put a shaft drive on a sport standard. To stop the harsh suspension jacking you usually get from a shaft under heavy throttle, they integrated a rubber-damper cushion in the rear hub. The result is a clean, bulletproof final drive without the grease splatter.

But it is not a perfect machine, and the 1980s engineering has a dark side. It is heavy, tipping the scales at over 500 pounds wet. Honda also bolted on a 16-inch front wheel—an '80s handling fad. Then there is the TRAC system on the front forks. Torque Reactive Anti-dive Control is a mechanical-hydraulic valve on the left fork leg. When you grab the front brakes, the caliper torque activates a valve that restricts fork oil flow, stiffening the front end to stop brake dive. On paper, it is brilliant. On the bench, it is a complex plumbing nightmare.

Right now, we are dealing with the mechanical reality of a bike that has sat neglected. The front brake calipers were completely removed before the bike even arrived at the shop. We are rebuilding those dual calipers, along with the brake and hydraulic clutch master cylinders, using customer-supplied kits. The clutch slave cylinder is getting a fresh K&L rebuild. When we drained the carbs, straight varnished fuel poured out. The entire inline-four rack is getting torn down for a deep ultrasonic solvent bath, body re-sealing, and a precision bench synchronization. The vacuum petcock is getting rebuilt, and we are chemically flushing the tank.

Finally, we are stripping off the rock-hard 2010 front and 2009 rear tires to mount and balance a fresh set of Bridgestone BT46 tubeless tires.

Despite the heavy lifting required to wake it up, the Nighthawk S features a bulletproof engine with a maintenance-free drivetrain and lines that still look mean forty years later. It is exactly what happens when you try to regulate a Japanese engineering department. Once this heavy recommissioning is done, we will get this tariff-beater back on the Atlanta asphalt.