Author Topic: CB550 Cafe Interceptor - Gentleman's Roadster (Read 488362 times)

FunJimmy · « **on:** October 12, 2007, 04:19:11 PM »

I'd like to preface by saying that the SOHC4 Forum has been very inspiring and incredibly informative.
I've always had a hankering to own a vintage racer and this site with all it's helpful members has made that realization possible.

I've been following most if not all project bikes and thank all of you for sharing your photos, ideas and stories with us.

This is my story. I hope you enjoy it and find it valuable.

I purchased a '77 Honda CB550F in January 2007, and immediately started collecting pictures, ideas, and parts for the eventual cafe project.
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 final picture is how the bike looks now. I hope you like it.

FunJimmy · « **Reply #1 on:** October 12, 2007, 04:20:15 PM »

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 solid wooden pedestal to raise the bike about a foot and a half off the ground.

FunJimmy · « **Reply #2 on:** October 12, 2007, 04:21:07 PM »

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 1999-2004 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 · « **Reply #3 on:** October 12, 2007, 04:22:01 PM »

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.

FunJimmy · « **Reply #4 on:** October 12, 2007, 04:23:23 PM »

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 · « **Reply #5 on:** October 12, 2007, 04:24:18 PM »

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 1/4"over the head tube for a clean finish.
Anodized black and it'll look factory!

FunJimmy · « **Reply #6 on:** October 12, 2007, 04:30:47 PM »

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.

rlarkin70 · « **Reply #7 on:** October 12, 2007, 05:09:25 PM »

Looks fantastic. I like the mix of new and old, and certainly the handling with the R6 forks will be light years ahead of the stock setup. I will be keeping an eye on your progress for sure.

What do you have planned for the back end? Also, I am curious what controls are those on the bars?

Good luck with the project, and keep those photos coming.

-Ron

cben750f0 · « **Reply #8 on:** October 12, 2007, 06:22:11 PM »

lookin really good M8... keep us posted!!!!...

peace

ScottB · « **Reply #9 on:** October 12, 2007, 09:43:42 PM »

Jimmy,

I'm glad to see this come together for you. Lots of planning - great work.

FunJimmy · « **Reply #10 on:** October 13, 2007, 08:17:57 AM »

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 · « **Reply #11 on:** October 17, 2007, 11:56:14 AM »

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 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 piston caliper and floating disc is a must!

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 · « **Reply #12 on:** October 17, 2007, 11:58:06 AM »

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 accordingly.

Photo of a stock hub before and after machining.

I've always been the type of guy that designs parts on a cocktail napkin before making my one-off parts so duplicating the process is almost as time consuming the second time as it was the first.
I have great respect and admiration for Franky taking the time to provide drawings and dimensions for the parts. Thanks Franky!

Note: You will require a metal spacer between the hub bearings. This spacer must have an ID the diameter of the axle OD and fit exactly between the hub bearings.

Below are some jpeg images of the drawings and here's a link to a scaleable PDF file http://www.franky.dk/Honda/franky_fork-spacer-drawings.pdf .

Overall drawing

Left Spacer

Right spacer

FunJimmy · « **Reply #13 on:** October 17, 2007, 12:03:31 PM »

Hub complete with billet aluminum spacers and a '95-'98 Honda CBR600 F3 rotor mounted.

FunJimmy · « **Reply #14 on:** October 17, 2007, 12:07:17 PM »

Here's the wheel laced up with an Akront 2.5" x18" alloy rim, stainless spokes and a meaty 110/90-18 Bridgestone BT45V tire.

FunJimmy · « **Reply #15 on:** October 17, 2007, 12:08:21 PM »

There is a much more aggressive look and feel to the front of the CB550F now that it's all put together.

volthause · « **Reply #16 on:** October 17, 2007, 12:10:31 PM »

Great thread! *subscribed*

750essess · « **Reply #17 on:** October 17, 2007, 12:25:56 PM »

Funny Jimmy, I like the way you bored out the hub and used the spacers to mount the bearings. It is simpler than my setup. Any concerns about the bolts coming loose though? I used the cb750 axle on mine and I have some flex, am currently fitting the bigger axle with new bearings with a bigger id of 20mm. IMO turning down the steer tube would be best. Very cool set up.

rlarkin70 · « **Reply #18 on:** October 17, 2007, 12:58:48 PM »

Jimmy- Looking GREAT! That thing should stop on a dime now. Just remember what bike you're riding when you grab a handful of front brake. =D

FunJimmy · « **Reply #19 on:** October 18, 2007, 11:08:40 AM »

The Brembo 4 piston monobloc calipers found on the Yamaha R6 are real nice.
These calipers are very light and extremely rigid, but fairly thick from side to side and left as is they will hit the spokes of a laced wheel.
Milling the caliper mounting tabs and the back side of the caliper will provide all the clearance needed.

Turning parts on the lathe is pretty easy when you have access to a good lathe, but milling is a little more challenging when the milling operations are performed on a drill press fitted with an inexpensive compound slide table and an end mill.

Careful measurements to provide true, level and square setup will ensure that the brake pads contact the rotor evenly.

cben750f0 · « **Reply #20 on:** October 18, 2007, 11:19:17 AM »

M8 it looks bloody awesome, like the way you have stuck to the one disc set up, keeps the older look, but has that modern tweak, sensational

peace

750essess · « **Reply #21 on:** October 18, 2007, 11:56:57 AM »

Yeah the hub is assymetrical on the 750 too. The faces where the rotors mount are even but one wheel bearing is deeper in the hub so the retainer can be screwed in. When you think about it there isnt much holding the bearings in position from side to side in the stock hub, only that left bearing is captured in the hub! You could use a honda 600 triple trees if all else fails, if the tubes are the same.

FunJimmy · « **Reply #22 on:** October 18, 2007, 12:05:03 PM »

Milling the mounting tabs 3mm to move the caliper closer to the fork leg will provide most of the needed clearance.

dusterdude · « **Reply #23 on:** October 18, 2007, 12:35:38 PM »

dude,that thing is tight!!!

StrongPerf · « **Reply #24 on:** October 18, 2007, 01:22:26 PM »

I like your approach!

I think your upper stem bearing is fine and like the cover you made. Since it appears you have access to a lathe, perhaps you could make a spacer ring that presses into the 48.5mm tube upper and would bring the dimension down to a bearing race outer diameter that is more common like say perhaps 45mm. You would of course have to make it thin enough that the bottom shoulder would still keep the new smaller race at bay. Not sure if it's possible but just a thought.
Like I said though you're probably fine like it is.

Love the front rotor mounting hubs!

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Author Topic: CB550 Cafe Interceptor - Gentleman's Roadster (Read 488362 times)

rlarkin70

ScottB

rlarkin70