Topic: Blue Falcon - Honda CB 550 Street Racer

[Oette]

Hi folks,

After being a passive member of the SOHC4 community for almost 2 years (studies, internships in Munich and San Francisco) I am back in Germany and brought not only quite a few extraordinary memories but also the urge to start a more consequent build and refurbish my already cafe'd CB 550.
I guess some people would call that withdrawal effects, well... it might be.

However, I made quite a few steps in this build already and documented every move with pictures. For a proper introduction, let me tell you the whole story.

Some might remember this bike, as the color was quite outstanding. It has been a reliable companion for almost 5 years now, carried me around in Scotland for almost 3000 miles without even having a single misfire.





After participating in the famous 'Glemseck 101' sprint race in 2015 I started my long lasting internship trip and had the bike covered in my garage.

For those who are interested in some of the numerous previous modifications, please refer to this old thread here: http://forums.sohc4.net/index.php?topic=86356.0

During my stay in California I felt a little homesick in terms of bike building, so I hunted down this old 22 liter race tank on ebay, which is quite rarely to get here for the CBs. It pretty much all started here.
Getting back to Germany I am on a little vacation between my masters studies and the upcoming PhD in August, so I started to sketch the bike around this tank a little further and remembered a post about a pretty much racy Moto Guzzi Le Mans that fascinated me with the plain and lean style (find it here, awesome looking bike: https://www.blessthisstuff.com/stuff/vehicles/motorcycles/moto-guzzi-by-kaffeemaschine/).



Comparing that to the tank's view on the bike it was that particular moment when I knew where the journey will be going, so I collected parts for a similar bodywork but with regard to some subtle modern accessories.



A minimalistic electronic multiswitch, operating the whole bikes electronics centrally in a matchbox format and a new throttle lever where the first parts landing on my desk.

After having read about the Yamaha R6 front fork conversion roughly 100 times I did the math and after a quick pencil and paper session, I shot a cheap fork on ebay which should replace the maintenance-intensive and weakly breaking and handling original front end.



Disassembling and cleaning the upper fork brace





Converted the tank to a modern fuel cap due to the missing original one. One more small modern piece on the bike that greatly merges into the tank's shape.



Dialing in the front wheel hub



and making the long process short by turning it down to the measurements that I collected here in the forum.



At this point I really have to credit the authors and thank you all for gaining and preserving such a broad knowledge to keep these old bikes and their variants on the road for some more decades!



Meanwhile I ripped the bike apart and sold some stuff like the forks that will never return to the machine to get some more cash for more build measures.

[Oette]

As I have no access to a CNC machine shop, I decided to manufacture the adapter plates for the front hub manually.

Turned them on the lathe



And used the mill to drill the holes for all the screws before cutting all the threads into it by hand





Rebuild the forks with new seals and the CB 900 disc setup



and solved the spoke clearance issue by removing 2.2 mm from all the brackets and applying a small angle to the back of the calipers (8 degrees)





Meanwhile the new clip-ons arrived with the four micro-switches for the bike's lighting and horn mounted for visual inspection. It is accompanied by a hydraulic clutch lever as the clutch will be converted to hydraulic.



Got my hands on a barely used set of CR 29 carbs and tore them apart for ultrasonic cleaning treatment





Mounted all the levers on the clip ons with small indicators and new grips - looks really clean!



Applied a small gimmick to the ugly hollow brace nut 



And stripped the frame from all unnecessary bolts and braces which once accommodated the original foot pegs and brake levers. Then repainted all these small blank spots in the same color again.



Threw in the fork after dealing with the bearing covers and steering lock



And had a first chance to see if my custom made rearsets will fit the frame and looks. And they do!



While the rims where at the shop for new tires, I installed the steel braided brake hoses





Marrying the engine to the frame again unveiled the really 'modern classic' look that this fork combination applies to the bike. The fork is incredibly more stiff and finally those will be brakes that can handle the output of the 660cc engine with hot cam, porting, valve job and so on...





Attached the lever linkage to the footpegs - solid titanium:



Same for the other side after making a first prototype for an angled brake linkage

[Oette]

Here comes the third and last part of the progress on that build so far:

The footpegs also clear the kickstarter effortlessy:



I felt that the exhaust system that originally was designed for the CB 550 had too much limitations in throughput because of a resonance based dampening system. That said, I scraped the materials together and started designing an absorption based damper, designed for better exhaust gas flow to get the most out of the CR29s.



A conic reduction optimizing the internal gas flow into the absorption pipe



Filling the new system with glass fiber wool



And finally refurbishing the pretty much 'raped' exhaust system that suffered some stains after running forever and ever, even over Scottish roads.

Before





And after -  as good as new!



As I have no bending machine, I started bending and drilling the brackets for the front fairing by hand on my workbench. After some small adjustments this is the framework that holds the fairing in place.





it all comes together slowly....







And lastly, this is where I stopped my garage time yesterday.
I cleared the fairing from excess material and brought it into a neater shape to compliment the bike's proportions. While doing so, I cut the hole for the new headlight which absolutely fits into the fairing's shape and made a bracket to hold it in place.







The bracket bent from aluminium:



The brake fluid reservoirs take their place on the drilled fairing brackets and the clutch is installed and already working.



To give a short insight into the more 'unofficial goals' of this project:

First:
The bike ran exactly 192 km/h (120 mph) on GPS before this rebuild. I set myself the goal that I stop modifying it when it hits the magic double metric ton of 200 km/h. Why is that? I don't know. Just keen to prove that it is possible with that old lady.
One of the reasons for the R6 forks and CR29s to step into the game...

Second:
Nearly all unnecessary weight other than everything necessary to operate the bike street legal in Germany is removed. Plus the fact, that I cant afford an aluminum tank and seat combo, I plan to land at less than 175 kg (386 lbs) for the whole setup (to win a bet against my uncle haha )

I'll keep you updated on progess with seat, bringing the fairing windshield into place.
Also I plan to attach a small oil cooler. However, I am still manufacturing and collecting everything necessary.

Now it's bed time over here so I'll leave you guys with these first impressions.

Best

Oette

[Stev-o]

Very impressive!!!   Subscribed to follow along...

[SOHC4 Cafe Racer Fan]

Glad to see this one again.  I like the fork conversion. 

For those who are not familiar with Oette's bike, it features a 650 top end on a 550 bottom end (retaining the crankcase and kickstarter.

[flatlander]

very cool.

how is it in germany with those stricter regulations: do you need to get every part that you make or modify approved for roadworthiness?

[Oette]

Hi,

Thanks for that welcome here again.

In general it's not too strict in Germany as long as the work is executed in a technically solid way. It furthermore depends on who is inspecting the bike for road worthiness.

With bikes build before 1986 noise and emission regulations are pretty loose too. However, some critical features must be found on the bike which are proper lighting, mirrors and tanks fabricated from metal (no fiberglass or carbon because of burst risk)

[flatlander]

ok that's lucky. from what i heard, i thought that regulations were super strict there with regards to aftermarket parts and modifications and that you needed to get specific approval for any deviation from the factory configuration. glad to hear it's not quite that bad.
here in the netherlands... you can do whatever you want. there is not even a yearly roadworthy test for bikes like there is for cars.

[Oette]

You, my friend, live in a bike paradise! If I get in trouble I rent a room in NL to get the yellow license plates 

[flatlander]

screw the yellow plates. the old dark blue ones are much nicer 

[Oette]

Something happened in between...

I adapted the CR29 carb spacing to the specs of the CB 750 carbs I had on the bike before and set up a pre-jetting which according to collected information should meet the requirements quite precise.



That's how it looks like now and they are ready to throw them on to the bike.



As the old box housing the electronics and so on has gathered too many useless holes and brackets over time, I decided to quickly build a new one.



After that I set up my sheet forming tool and started with the seat / hump combo, which lines have to follow the frame and therefore are quite a little bend.



First shot first goal.



After a short session of organ donation, the seat comes slowly into shape.



On the bike:






After seeing this I decided about 2 changes to follow:

1) The hump has been angled / shortened according to the yellow markings
2) The hump's rear end will be shaped a little different to get away from the quite square looks. For that I'll cut the thing and weld it again sometime within the next days.

But here is the result for the meantime:





Once I am confident with the looks, I'll apply all the welds.

Best

[SOHC4 Cafe Racer Fan]

I agree as to the squareness.  It would help if the straight lines (ridges) were less pronounced and more curved.  Just my $0.02!

[kpier883]

Subscribed!

[Oette]

Since my last post there has been something going on here. Let me tell you the story:

I bend the new adapters for the oil cooler feed



Threw it on the bike and it looks perfect and is in the position as intended and measured, so that I can run the hoses to the oil cooler up the frame in the front.





As I found the new hump far too bulky I changed it a little to compliment the bike better. To do so I cut out a significant amount from the hump.



First try on the bike reveals the better shape





The place for the BMW oil cooler is already found. It is neatly merging into the frames shape and doesn't appear to huge.



Went on with the seat and integrated the brake light



In combination with the newly shaped hump the bike's look is far better than earlier







I still need to cut the windshield into shape though...

Some more progress with some smaller things which are the following

I bled the brakes so that the 4 piston calipers are ready to bite the discs now.

Welded in a bracket to mount the seat on the rear frame. Everything will be powder coated before painting in the end.



The tank got it's mount too.



It is actually fulfilling a double function, namely retaining the battery in the electronics pan.



The rectifier was located under the pan to get sufficient air cooling.





Everything can be mounted securely on the bike now and looks as following when fastened



Small problems, small solutions: The spring for the rear brake switch wasn't long enough anymore, so a keychain took over a part of the function.



I finished the oil cooler adapters by soldering two rings onto the tubes which act as a retainer for the tube fittings later.





Some hoses for the oil cooler as well as new cables for the electrics are on the way, so there will be progress with that soon.

Best

Oette

[Oette]

Today the oil cooler has been married to the frame. It actually looks better than the wide OEM version Honda sold with the CBX bikes IMO.







The oil line adapters are practically in line, waiting for the hose to connect them to the cooler. These parts will come in within the next days I think. Then the engine is ready to be filled with oil again 

[greenjeans]

Looks great.   Seat and tail combo looks good.  Really like the single tail light.

[SOHC4 Cafe Racer Fan]

Nice changes.  Good work on the seat (slimming it down and installing the brake light).

I like the oil cooler.  I'm going to run one on my 650 since it gets some balmy here in SoCal combined with some nasty stop and go traffic.

[Gene]

have to see how it ends up. looks great.

[tiretread]

Amazing work! I loved riding/living in Germany.

[SOHC4 Cafe Racer Fan]

Oette,

Is the gas tank aluminum or steel?  I saw that you "hunted" it down.  Was it a vintage part?

[Oette]

Hey guys.

First, let me answer the question:

Tank is vintage aftermarket steel tank from a German manufacturer ;-). Super hard to get here in a good condition.

Second: It took me some time to finish my graduation and get some other things on track. Bike is pretty much finished now, just the fairing windshield needs to be shortened. However, I am very probable relocating to California by mid of September, so I am giving it into the hands of my uncle for cyclic runs, polish and care for at least the next 2 years.

Let me show you some pictures of the (nearly) final product and the last steps it took to bring it there :-)

Questions? I'm happy to answer!

Oil cooler attached, hoses clamped and ready to roll!




Two days of wiring to get the button-operated electric system going


Meanwhile, all other parts were sitting at the paintshop waiting for the first layer in Long Beach Blue Metallic. Coming back, it looks like this:







After a round of sanding, marking the spots for some silver lines on the tank and waiting another week, parts returned from the paint shop, which did a BAD ASS JOB!
(Please do not complain about our huge German license plates. Trying to get a smaller one but it sucks in general  )













Windshield needs to be shortened soon, bike is running well till 3/4 throttle. I will have to sort out some minor issues with needle position and main jet once I am back from Sweden next week.

Best

Oette 

[02z06dave]

I dont know how i missed this thread before, but DAMN! Job well done. Looks like a future bike of the month

[Gene]

Nice job.

[SF]

Fantastic job! I like the blue


Sent from my iPhone using Tapatalk

[flatlander]

not sure what's going on but i can't see the pictures.
more importantly: how do you know you can trust your uncle? you should just leave the bike with me instead, i'll take good care of it