Topic: 1976 CB550F Super Sport

[Gary in NJ]

I bought a non-running 1976 CB550F Super Sport 3 years ago and I've been waiting until I retired to do a full restoration on this bike...and I retired on August 1st. Time to get crackin'.





I bought this bike from an 18-year-old after he had owned it for a summer. I know...sounds like a red flag...probably is. The bike wasn't running right for him so he decided to rebuild the carbs...took them a part...and got in over his head. I met both the young man and his father at his father's garage. Dad is in the heavy equipment business. He wasn't happy about his kid getting a motorcycle...and let him get into the project to see how it went. He assured me that the bike is a runner, but it was running too rich. The bike has about 30,000 miles on it.

Overall the bike is in fair condition. It looks like it was largely garage kept. There is some corrosion on the fork caps and shock bolts. The tank is in good condition as are the side panels (the left is a little warped on the top edge due to what appears to be a fried circuit in the fuse box). It looks like the owner at that time moved the fried circuit to the spare to the right. I'll investigate.



I have been giving the bike some thought for a few weeks, deciding how to tackle a non-running project that I want to do a full restoration. My thought process is to first get it running to see what else needs attention. To that end I got the bike up on my stand and gave it a compression test. Since the bike has sat dormant for years, I figured a wet test would be needed. The factory spec for compression is 170 psi, with an acceptable range of 153-170 with no more than 10 psi varriation. The battery is holding a steady 8VDC...so the kick starter came in handy.

Round one: With 10 kicks cylinders 1-3 show between 50 and 54psi. Cylinder #4 shows 53psi..I give it an extra kick and the reading jumps to 75psi. Hmm...I wonder of 1-3 will show a similar improvement with a few additional kicks?

Round two: Cylinders 1-3 show between 75 and 78psi. Cylinder #4 now shows 110psi. I like where this is going.

Round three: Cylinders 1-3 show between 120 and 125psi. Cylinder #4 now shows 148psi. Let's do this one more time....

Round four: Cylinders 1-4 show between 152 and 155psi. No need for a wet test. I'm in range with a stone-cold engine.

So the other thing I have to do to get this bike started is to rebuild the carbs. When I got the bike I received an assembled carb bank, and a bag of removed parts. The bag of parts looks complete, but I've ordered a carb kit because I have no idea the condition of the brass and all of the rubber is dry (o-rings and boots/isolators). I now have the carbs completely disassembled and ready to go through my Vapor Blaster and Ultrasonic cleaner.



Hopefully I have the bike running in a few weeks. I have a new battery on order, and by the time I get the carb rebuild parts I should have everything cleaned and stagged for reassembly. I'm hoping the engine runs well...but if not I'll fix what is needed. I'd rather not rebuild the engine... I do plan on painting the engine...so if I have to rebuild the engine it does make painting a lot easier. We'll see.

[Mark1976]

   Before going any further, lets identify what kinda of brass you currently have in your carburetors, and then identify what type/brand of carb kits you've purchased. If you don't have the original kehin brass and needles you're going to struggle getting the carburetors to perform as they should with aftermarket brass, needles and o-rings.
   Looks to be a great starting point, 550f's are great bikes...

[Gary in NJ]

Thanks for the reply Mark. The brass is aftermarket. I'll likely go with a 4into1 kit just to get the bike started...and then swap out for Keihin brass before I have to wrestle with the final fitment of the airbox/carb bank.

Looking at the spark plugs, the existing jets are clearly too rich. Of course being a who-know-what brand, what is imprinted on the jets may not be close to what they actually measure. I also have a janky exhaust system on this bike. A previous owner "modified" the beautiful OEM header by cutting the pipes before the collector...realized his mistake...and "repaired" the pipes with exhaust wrap. This is silenced with some kind of shorty muffler. I'm sure it sounds like hell unleashed...but it could also result in the black spark plugs due to loss of back pressure and poor scavenging.

The good news...I did score a replacement OEM 550F header on FB Marketplace for $25, and it's in very good shape. I can't seem to find a muffler with a 2-1/2" inlet anywhere. What are others using?

[denward17]

Nice start, following for progress....

[scottly]

I now have the carbs completely disassembled and ready to go through my Vapor Blaster and Ultrasonic cleaner.

I wouldn't use the Vapor Blaster on the inside of the carb throats or the slides.

[Mark1976]

Thanks for the reply Mark. The brass is aftermarket. I'll likely go with a 4into1 kit just to get the bike started...and then swap out for Keihin brass before I have to wrestle with the final fitment of the airbox/carb bank.

Looking at the spark plugs, the existing jets are clearly too rich. Of course being a who-know-what brand, what is imprinted on the jets may not be close to what they actually measure. I also have a janky exhaust system on this bike. A previous owner "modified" the beautiful OEM header by cutting the pipes before the collector...realized his mistake...and "repaired" the pipes with exhaust wrap. This is silenced with some kind of shorty muffler. I'm sure it sounds like hell unleashed...but it could also result in the black spark plugs due to loss of back pressure and poor scavenging.

   There's a short list of items that create a rich condition, and unfortunately using that 4into1 kit most likely won't solve any of them, they're just junk kits... look its your money and your bike, do as you please, but buying and installing 4into1 junk is a waste of time and money. Getting the carburetion side of the equation right the first time around will save you time and untold frustration. And pulling a rack of carbs on a stock 550f is a immeasurable PIA. Right about the third time I'd done it my first thought was, "I'm not doing this again if I don't have to."
   But again, your time, your money, your bike....

[carnivorous chicken]

Looks like you've got a good solid base to work with. Always curious to me when someone would pair a cafe racer seat and chopped rear fender with the stock (huge) turn signals -- maybe they didn't get far enough along to replace them. I just put a '76 550F1 back into original shape -- I guess I technically could say "nut and bolt restoration" because I replaced a lot of janky hardware and allen head bolts, but it's also just a very clean rider.

Bummer about the exhaust, but good to know you've found a header at least. Not sure where to find a muffler. Mine's stock but it came with the bike, and I've poked around a little looking for another but come up blank.

For the carbs, this is certainly true:

   And pulling a rack of carbs on a stock 550f is a immeasurable PIA. Right about the third time I'd done it my first thought was, "I'm not doing this again if I don't have to."

But it is also possible to (very carefully) switch out internals like jets and float valve with the carbs on (although I broke a float tower doing it months ago...). I switched out allen bolts for the stock JIS for the float bowl screws, only thing I kept allen bolts on. I had taken the carbs off and on a few times after replacing the pods with the stock airbox and while tinkering to get it running right at altitude -- I'm at about 7500 feet elevation.

The stator cover plate is still available -- I think I got mine from CMSNL.

I've got a spare set of 069A carbs for the 550F with original brass. I bought a spare set, and an extra carb, and then found another super clean set at Bob's Salvage in PHX. I'm selling the rack for what I paid for it: $125 + shipping, and it's all there, just needs to be cleaned. HMU if you're interested, and best of luck.

[Mark1976]

Looks like you've got a good solid base to work with. Always curious to me when someone would pair a cafe racer seat and chopped rear fender with the stock (huge) turn signals -- maybe they didn't get far enough along to replace them. I just put a '76 550F1 back into original shape -- I guess I technically could say "nut and bolt restoration" because I replaced a lot of janky hardware and allen head bolts, but it's also just a very clean rider.

Bummer about the exhaust, but good to know you've found a header at least. Not sure where to find a muffler. Mine's stock but it came with the bike, and I've poked around a little looking for another but come up blank.

For the carbs, this is certainly true:

   And pulling a rack of carbs on a stock 550f is a immeasurable PIA. Right about the third time I'd done it my first thought was, "I'm not doing this again if I don't have to."

But it is also possible to (very carefully) switch out internals like jets and float valve with the carbs on (although I broke a float tower doing it months ago...). I switched out allen bolts for the stock JIS for the float bowl screws, only thing I kept allen bolts on. I had taken the carbs off and on a few times after replacing the pods with the stock airbox and while tinkering to get it running right at altitude -- I'm at about 7500 feet elevation.

The stator cover plate is still available -- I think I got mine from CMSNL.

I've got a spare set of 069A carbs for the 550F with original brass. I bought a spare set, and an extra carb, and then found another super clean set at Bob's Salvage in PHX. I'm selling the rack for what I paid for it: $125 + shipping, and it's all there, just needs to be cleaned. HMU if you're interested, and best of luck.

Buy the extra rack, it makes the process much less difficult, and if its got good brass ya just solved possibly your biggest issue...

[Stev-o]

Nice project, I love the 550F's.  +1...dont waste your time with any aftermarket kits and be wary of other cheap china parts from 4into1. 

I might have a muffler, not 550F original, but similar, I will check the size.


PS. Hondaman sells a nice plug & play fuse block...

https://sohc4shop.com/blade-fuse-holder

[Gary in NJ]

Thanks for the input.

Scottly - I have a lot of experience with Vapor Blasting. I use a 170-325 grit on carbs. I hold the nozzle (@55psi) about 1/2-inch to 3/4-inch for polishing, and 1 to 2 inches for cleaning. The interior of carbs get cleaned only. After they go through the VB, they get rinsed and then go into the ultrasonic for 20 minutes at 122F. Here is #1 done:



Stev-o - thanks for the Hondaman link, I will be using that updated fusebox. Let me know about the muffler!

Regarding the brass, using my non-OEM parts as reference, it would appear that I need Kiehin part numbers 99202-601-98 for the Main and 99124-076-038 for the Pilot. What would be the OEM numbers for the Needle, Emulsion Tube, Seat and Float Valve (maybe 18-4762?)? Are those parts even available anymore?

[Stev-o]

 Let me know about the muffler!

Regarding the brass, using my non-OEM parts as reference, it would appear that I need Kiehin part numbers 99202-601-98 for the Main and 99124-076-038 for the Pilot. What would be the OEM numbers for the Needle, Emulsion Tube, Seat and Float Valve (maybe 18-4762?)? Are those parts even available anymore?

Sorry, the muffler is not the correct size you need.

The brass parts should be available here and is a trusted source...

https://www.jetsrus.com/a_jets_by_carburetor_type/a_jet_kits_keihin_selection.htm

And BTW - when searching for a specific part, Google the part number and it will normally come up in the search  [even if no longer available from Honda]