Topic: 1977 CB550F Super Sport brat project

[n8guy]

Background: I'm new here but thought I'd start posting some of my project, in case anyone is interested, or can help me avoid major mistakes before I make them.    I come from a woodworking background, and have done a very little bit of metalworking and mechanical projects.  This is by far my biggest project in this realm.  I'm mostly doing it on lunch breaks, so it's slow-going.

The plan: a functional, comfortable, brat-style cafe racer (with an open back triangle) in a classic, timeless styling.

Some design inspiration:

• http://www.wrenchmonkees.com/bikes/monkee-68
• https://godfferysgarage.com/wp-content/uploads/federal-moto-cb750-4.jpg
• https://www.bikeexif.com/honda-cb550f-super-sport
• https://i.pinimg.com/originals/e5/2c/6e/e52c6e95fc8ece3174c9f40f8fd75db9.jpg
• https://www.pipeburn.com/honda-cb550-cafe-racer/
• https://gyazo.com/e709cef6af6928326e7e2e262bd9fdf2
• https://www.dotheton.com/proxy.php?image=https%3A%2F%2Fmedia.discordapp.net%2Fattachments%2F490727445163671592%2F509152809317302282%2F2018-11-04_15.38.png%3Fwidth%3D878%26height%3D586&hash=d6a98aa5f84849e7967e041a8d115fc2
• https://i.ytimg.com/vi/J-4nkRqZ7Zc/maxresdefault.jpg

[n8guy]

Step 1: remove clunky OEM parts & getting started (Sept 2019)

I never wanted the cafe seat, just had it laying around from a previous project, and it helped with a bit of inspiration.

[n8guy]

Step 2: remove handlebars and controls (May 2020)




This might have been hasty, but in order to pull the wires out of the original bars, I thought the best way was to cut the main cable.  In hindsight, disconnecting these wires on the other end would have probably been better.



And this is me soldering and heat-shrinking them back together.

[n8guy]

Step 3: initial frame cutting and tab removal (May-June 2020)

Lots learned here.  Definitely some cleanup remaining.

[n8guy]

Step 4: rebuild carbs (April-May 2020)

HELP!  The small "t" was remaining after my rebuild (large "t" for reference).  Any idea where it comes from?!  I couldn't find a reference to it anywhere!



I found a cheap ultrasonic cleaner on Craigslist, and used some of the special aircraft-safe Simple Green in order to protect the parts.  The carbs were filthy and this was a long process (that would take me much less time now).

[SOHC4 Cafe Racer Fan]

n8guy,

You've likely thought of this, but after removing the rear crossmember (that acts as a mount point for the rear fender) remember to replace it with another cross-member or rear hoop.  Otherwise the rear of the frame will twist and be unstable.  If you are going to install a rear frame hoop, make sure to consider rear tire clearance. Under full compression, a rear tire can bottom out on a hoop.  This is why many builds incorporate a hoop that is kicked at an upward angle.

[n8guy]

...after removing the rear crossmember ... remember to replace it with another cross-member or rear hoop.

Thank you for the great tip!  I've actually already done this, just haven't documented it, since I figured ya'll would be more interested in seeing the step mostly completed.  Before cutting away any of the rear crossmember, I added a significant crossmember directly over the rear shock mounts.  I haven't yet welded in the hoop, as I've had a hard time sourcing one that will work with my seat (an upswept Tuffside).

If you are going to install a rear frame hoop, make sure to consider rear tire clearance. Under full compression, a rear tire can bottom out on a hoop.  This is why many builds incorporate a hoop that is kicked at an upward angle.

This is great advice, and something I've wondered about, but haven't put much thought into.  I'll be careful to take this into consideration!  And hopefully I don't have to remove the crossmember I already added.  Thank you!!

[SOHC4 Cafe Racer Fan]

...after removing the rear crossmember ... remember to replace it with another cross-member or rear hoop.

Thank you for the great tip!  I've actually already done this, just haven't documented it, since I figured ya'll would be more interested in seeing the step mostly completed.  Before cutting away any of the rear crossmember, I added a significant crossmember directly over the rear shock mounts.  I haven't yet welded in the hoop, as I've had a hard time sourcing one that will work with my seat (an upswept Tuffside).

If you are going to install a rear frame hoop, make sure to consider rear tire clearance. Under full compression, a rear tire can bottom out on a hoop.  This is why many builds incorporate a hoop that is kicked at an upward angle.

This is great advice, and something I've wondered about, but haven't put much thought into.  I'll be careful to take this into consideration!  And hopefully I don't have to remove the crossmember I already added.  Thank you!!

No worries.  Just trying to help you avoid issues many others have encountered.  Looking forward to see what you build.