CB550F Cafe Interceptor

[FunJimmy]

Some of you will recognize this bike as one of the bikes featured in the DTT Volume 1, Café Racers book, and I thought it might be valuable to some to see how it came together.

When I was a young lad in high school many of my classmates and/or their older siblings rode Honda CB550’s, 750’s and some of the Kawasaki KZ’s of the day, and I’ve always had a fondness for them, so after a lot of searching Craig’s list and Kijji classifieds, I finally found a good CB550F Super Sport in Edmonton.

This project began shortly after I purchased that little 550 in January 2007, but the build continues to evolve even today.

Before we get into the current stuff, I’ll give you the build from January 2007 till today.

This is the bike as I received it from the previous owner. You can see that it’s pretty much a dirty old stock CB550F daily rider.
 





The fruits of my labour.

[FunJimmy]

It only took the first ride to realize that priority number one was front brakes and suspension.
These may have been state of the art in 1977 but in this day and age, safety and control have evolved into much, much more.


Before I started tearing the bike apart, I built a nice solid wooden pedestal to raise the bike about a foot and a half off the ground.
 

[FunJimmy]

With that in mind I began searching for a modern fork assembly that would provide fully adjustable sport suspension without sacrificing the vintage look of the bike. Several late 90’s and early 2000 sport bikes where spec’d with conventional cartridge forks and after combing through them, I found that the 1999-2002 Yamaha R6 fork assembly was just about perfect.

Motorcycle geometry is quite the science, and I don’t profess to be a expert here, but searching the internet will provide lots of reading about the effects of rake and trail on the handling characteristics of motorcycles. What I did learn is that less fork offset equals more trail, and more trail will provide greater high speed stability at the expense of  fast light steering. The CB550 is well known for it’s neutral and agile handling, but this bike is (hopefully) going to need stability cause I want to turn it up a bit on the twisty bits.

The R6 triples have approx. 3/8” less offset than the CB550 triple and should provide slightly more trail and high speed stability. 
 

 

[FunJimmy]

The Yamaha lower triple is forged aluminum with a tapered and anodized steer tube. The steer tube diameter at the upper and lower bearings is 30mm whereas the CB550 steer tube diameter is 30mm lower and 26mm upper. This means that the Honda CB550 head bearings won’t fit. Thankfully All Balls Racing (www.allballsracing.com) can supply a custom selection of taper roller bearing to fit a multitude of different forks on our old bikes.
 

[squirley]

Jimmy,
It's good to see your on this site.  Your information and build quality are great and very valuable.  Have there been any recent updates to the Interceptor?

Jens

[FunJimmy]

Hey Jens
 
Nice to hear from you and thanks for the complements.
 
There's been some good things going on with the bike lately, but you’ll have to let me get caught up on the build history before I’ll give you the new stuff.
 
Mostly refinements and detail stuff.
 
Stay tuned.
 
Cheers
Jimmy
 

[FunJimmy]

As soon as I received the bearings from All Balls Racing I assembled the triples to check for clearances and was pleasantly surprised at how well it all went together.
The R6 steer tube is just about the perfect length for the 550 frame.
 

[FunJimmy]

To ensure the longest possible bearing life, the bearings must be protected from the elements.
This alloy bearing hood, covers the exposed bearing and extends ¼” over the head tube for a clean finish.
Anodized black and it’ll look factory!
 

[FunJimmy]

If you really wanted to make this an easy project, use the Yamaha R6 front wheel and brakes and it’s almost road worthy.
All you would need to get back on the road is some headlight brackets (these are Buell M2 Cyclone items), clip-ons (many available for 43mm forks), a bracket to mount the tachometer (currently no mechanical speedo drive available) and off you go.
You can see this front end fork swap only requires one custom made piece.
Many of you will have other ideas to make a bearing hood, but if you had one spun out of aluminum it shouldn’t really cost all that much.
 

[FunJimmy]

Fork stops are typically only required for parking and some tight lock to lock turns.
Most of us know not to smash the bars into our tanks, but stops should be provided, and I wanted to make a fork stop that didn't require welding to the frame.
If you look closely you will see that the metal stop is bolted to the factory fork stop and can easily be removed and replaced with a different unit if required.
 

[FunJimmy]

At this stage, the Yamaha R6 front fork assembly is pretty much mounted and ready to go, but decisions about the front wheel and brakes still need to be sorted out.

As mentioned earlier, using a Yamaha R6 front wheel and brakes would be easy and get this bike back on the road right away, but I’m after that classic vintage look, so let’s try using the stock CB550 hub and a spoke wheel first.

To do that, there are a couple of architectural issues to sort out. First, the R6 front forks use a large 22mm flex free axle to keep the wheel following a straight and precise path but the CB550 hub has a 15mm axle so larger bearings will have to be accommodated.

Secondly, motorcycles with spoked wheels use brake calipers with pistons on the outboard side only due to spoke clearance issues, and I want modern braking performance with only one disc to keep the stock look, so a 4 (opposing) piston caliper and floating disc would be ideal.

Another consideration is mounting a modern 300mm floating brake rotor. All of these goals can be accomplished by machining two large spacers to sandwich the front hub.

The spacers would be the diameter of the CB550 front hub/disc mating surface and as thick as required to provide clearance for the caliper with ’95 – ‘98 Honda CBR600 F3 rotor mounted. Honda CBR600 F3 rotors have a very similar 6 bolt pattern to the CB550 hub and have a substantial offset which will provide some of the clearance needed for the caliper.
 
Something like these!
 

[FunJimmy]

With the hub removed from the wheel, I chucked it in the lathe and machined the hub to accommodate the spacers. This hub will now accommodate any size axle and any rotor as long as the spacers are machined correctly.   

Photo of a stock hub before and after machining. 
 

[FunJimmy]

Hub complete with billet aluminum spacers and  a ’95 – ‘98 Honda CBR600 F3 rotor mounted.
 

[FunJimmy]

Here’s the wheel laced up with an Akront 2.5”x 18” alloy rim, stainless spokes and a meaty 110/90-18 Bridgestone BT45V tire.
 

 

[FunJimmy]

There is a much more aggressive look and feel to the front of the CB550F now that it’s all put together. Once the brake caliper is mounted I’m going to be working on a front fender.

I really like the sleek look of a ‘78 Suzuki GS750 fender, but they are too narrow for the 110/90-18 Bridgestone BT45V tire so I will have to cut my teeth at fiberglass fabrication.