I recounted the tales of woe I experienced while riding this 1978 CB 550 to a two-day Kickstart Classic event in Alabama, within the CB550 rear shock upgrade. The suspension largely contributed to the woe in that tale and the ache in my back.
We upgraded the rear suspension by installing a set of Progressive Suspension 12 Series rear shocks and springs. In this issue, we’re installing a Progressive fork spring kit. The kit we’re installing is made specifically for this bike, but Progressive has tons of fork spring kits available for just about any make and model.
When deciding to upgrade the old or stock setup, there are several factors to consider: fork oil weight, progressive or standard springs (see step 8), or even rebuilding the entire fork. The front end on this bike had no oil leaks and moved nicely on the stock slides, so it didn’t require a complete overhaul. Not yet, at least.
Ride quality and perceived expectations from a new set of springs really come down to personal preference. I always refer to the owner’s manual or a well-trusted forum board to find the bike’s factory specs, then build off the stock platform. In this case, the old CB had a bouncy front end and tons of chatter. So, I wanted to slow down the rebound and soften up the forks. I used a new set of springs that were close to the factory spec, but a heavier-weight fork oil.
An important thing to note is that fork springs are under a tremendous amount of pressure, and the energy stored in a compressed spring can really pack a punch. So be aware of this and use caution when removing fork caps. Elevate the front tire and stay out of harm’s way when doing this. Enough talk—let’s get started on part two of the CB suspension upgrade.
Adjustable wrench large
Fork spring kit $97/#11-1106
Spectro Performance Oils
Spectro Fork Oil $12.99/SAE 10