1975 CB550 - trip hazard phase1

canyoncarver

'hacking is learning'
DTT BOTM WINNER
So I've been here on DTT for a few short months, mostly reading, admiring builds, learning stuff and once in awhile popping off at the keyboard. I've been riding since I was about six thanks to my Dad but just started getting back into working on bikes in the last year or so. I've been reworking my garage space quite a bit over the last few months and have a nice setup now.

I've collected several project bikes and decided the one I want to ride first is the 1975 CB550. I literally tripped over the bike in a friends yard one night. Turned on my flashlight, saw it, and then talked him out of it for 150$ and a promise that I would get it running and ride it. It had been sitting awhile (7+ years) outside but stuff doesn't really rust here around Albuquerque. Best of all, I know the original owner of the bike and have a clear title.

My plan is to get it running first. It'll take alot of work to get it there, so time to nut up.
- Rebuild the carbs - using modified original airbox with K&N Unipod mod.
- Build a new wiring harness, starting with basic stuff first, starter, etc..
- New coils and upgrade to either Dyna or Hondaman ignition( orig coils & wires are toast)
- Rebuild forks, add progressive springs, fork brace, replace rear shocks (PO is 6'7", 280lbs)
- Tank was previously coated, so strip, clean, re-coat
- Make a seat
- and all the other required stuff to get it running

I'd like to avoid opening the engine until the carbs and electrical are done so I can hear it run and hopefully ride it a bit before the inevitable teardown.

I appreciate all helpful feedback, especially safety and performance info. I started a pseudo blog over here: http://kellysgaragedotnet.tumblr.com but figured a real build thread here on DTT will help keep me going.

This is already a work in progress so a few posts to catch up.

Here it is the day I picked it up:
 

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Re: 1975 CB550 - trip hazard

29, 518 miles on the Odometer so I'm guessing it'll need at least a top end
 

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Re: 1975 CB550 - trip hazard

Got it in the garage, stripping off all the broken, dirty, useless stuff.
 

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Re: 1975 CB550 - trip hazard

Took 'er out and hosed 'er down.
 

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Re: 1975 CB550 - trip hazard

Got the carbs pulled and on the bench.
 

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Re: 1975 CB550 - trip hazard

I did a bit of 400/800 sanding of the intakes, then a bit of polish to clean it up. There was enough irregularities that I figured this will help the airflow. BTW, the red compound doesn't do much...
 

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Re: 1975 CB550 - trip hazard

Bookmarked! Can't wait to see what happens next!
 
Here is my intake polishing setup. The good kind of ghetto.
 

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Inside of the carbs was gooey, black, sticky mess. Carbs 3&4 slides were totally stuck.
 

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I wouldn't worry about polishing the intakes. Grind out the chunky bits and sand it down to 220 grit and you should be fine. The boundry layer of the moving air makes polishing a waste of time and effort. Plus, a little turbulence helps keep the fuel suspended.
 
Also picked up a stainless hex bolt kit for the engine online but decided to make my own for the carbs by visiting the local hardware store.

My new stainless carb hardware:
8x carb tops 5x16mm .8 pitch
2x idler bracket 5x10mm .8 pitch
2x cable perch 6x16mm 1.0 pitch
16x float bowl 4x10mm .7 pitch
 
Sonreir said:
I wouldn't worry about polishing the intakes. Grind out the chunky bits and sand it down to 220 grit and you should be fine. The boundry layer of the moving air makes polishing a waste of time and effort. Plus, a little turbulence helps keep the fuel suspended.

I didn't try to get them anywhere near perfect. I'd read they need a bit of turbulence but good info.
 
Hell yeah I like it. Original pipes in good shape are always cool. I left mine on. Although I am thinking about taking them off and getting 4-1 to keep the original ones from getting too rusted out.
 
Cloyd said:
Hell yeah I like it. Original pipes in good shape are always cool. I left mine on. Although I am thinking about taking them off and getting 4-1 to keep the original ones from getting too rusted out.

Thanks Cloyd. I'm leaving them on for now. They seem to be in nice shape. I can't decide if I'd rather have a 4-1 or a 4-2 eventually though.
 
My brother has a mac 4-1 on his 1975 cb550 and it sounds pretty good.
 
Cloyd said:
My brother has a mac 4-1 on his 1975 cb550 and it sounds pretty good.

any chance you have a video of it running to hear it?

I like the Mac, it's period correct and does sound good. I have one on my 81'CB750 (also a work in progress)
 

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Not currently but it sounds very similar to the mac I had on my sohc cb750
 
4 into 2 is a classic period-correct modification. Jardine mufflers :) Put the original pipes in a warm dry place and keep them.
 
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