Topic: 1977 CB550F Desert T-Rex

[minimo]

I recently purchased a ‘77 CB550F via a young ex-pat in LA allegedly making his living buying old cars and shipping them back home to the motherland (aka his uncle’s garage in London). His purchase of an old Ford came with some other contents of a small garage unit out in the California desert and that’s how this 550F came along. No plate. No paper trail. No history. Just some decades of old oil caked in dirt and dust and cobwebs and hornet nests.

Lots of oil spread around the gear shifter (easy seal replacement). Of course, the bike wasn’t running but the engine rotated with the kickstart which was a good sign. Master cylinder and front brake needed some love. Beyond that the bike needed a lot of cosmetic work though the metal side covers were seemingly clean with no sign of them being hit nor dropped. The carbs had numbered engravings on them - somebody’s been in there, maybe someone who cared. Missing ignition key. In my mind, I figured it’d be nice as a donor bike. The guy was asking $800 but we shook on $400 and like that, the bike was mine.


Tear down began immediately

With some surprises along the way





Oh, and here’s the T-REX reference

...because I imagine it was being ridden around the deserts of CA by someone with short arms

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[minimo]

Made an attempt to spot weld the gash on pipe #1, which is underneath on the leftmost side so it’s kinda hidden, but it only left a larger hole. I ended up trying to cut out a neat-ish square and then jigsawing a metal piece in there but it wouldn’t give


Yikes.

Well, now since the aim is to get the engine to turn over, I’ll wrap and clamp some exhaust gasket material to patch it with some of this and then sheath it with some thin tin sheet material and hose clamp it.

I am open to suggestions - of course aside from buying a new exhaust system. I’m eyeballing this set on Amazon:

Honda CB550F Supersport 4-1 Exhaust System Classic Muffler Stainless Steel 75 76 77 https://www.amazon.com/dp/B0747XDP22/ref=cm_sw_r_cp_api_RSDrAbV1KFCCA

[JoeCooley]

Nice start to a cool project! The engine looks to be in good shape. No major oil leaks or signs of neglect.

[calj737]

As badly rusted as that exhaust is, the interior is probably rusted worse in a much larger area making the metal paper thin. Good luck trying to weld it... About the best you might get away with is brazing a patch over it, but the exhaust will still be worthless for any length of time.

[strynboen]

that battery have done the job.

.and eating the exhosts..and korodet the frame..think a glass blast is the only vay to stop the accic..and/or some kemical mix to neutral the damage, before paint..

[SOHC4 Cafe Racer Fan]

All things considered, the motor turns, the wheels are in decent shape and the frame looks unmolested.  How about the tank?

[Stev-o]

Nice project, subscribed. I'd buy the Del exhaust....

[minimo]

Thanks, y’all.
The tank is in pretty crap condition. I guess it could be worse, but I’m gonna try to make it work with a little rinse out this weekend.

Meanwhile, got some more parts cleaned, slightly polished, and prepped for installation

And I was being real meticulous with these puppies

Strynboen, I employed your compressed air method to judge the float heights - I think this time I got it. For those of you not familiar, it’s where you link a low-pressure air line (I used one from my airbrush compressor) to the fuel line on the carbs and get the air up yet low enough to test each float height one at a time. You can keep the floats down with rubber bands as you’re measuring one at a time. So basically, the hiss of air represents the fuel. It’s definitely less mess (and that’s what you’re about, right, strynboen? :-D) I get the principle of it now but we’ll see soon enough on how well I executed this method. I find that it might help to be in a very quiet space to hear the hiss of air as the tangs release from the float valves. Very cool trick. I hope it works out.


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[minimo]

I’m happy with the way my seat turned out. I patched a big chunk of foam that was bitten off with a slab I had laying around from a previous project and used 3M spray adhesive 74 (a bit chunkier than 77 spray) to make the contact bond.

Then I took my angle grinder with a sanding wheel and shaved the seat down to a shape I felt was appropriate for the tight seat cover I purchased via eBay from some fella in Florida, seller name, “hondasvintage”.
Then, one of my better decisions was the purchase of this:
Upholstery Tack Strip - 5 Pack by Online Fabric Store https://www.amazon.com/dp/B01AVV5BLU/ref=cm_sw_r_cp_api_ei0rAbTV72H6X
The metal spikes have had better days on this seat (50% of the upholstery spikes had broken off) so I had to find some way to attach the replacement seat cover. Well, this was probably the best $12 I spent lately. It’s a bit of a process to attach (with aluminum rivets) but I took my time with it and I think the results came out pretty good

Oh, and whoever suggested wrapping the seat tightly with plastic food wrap to compress the foam, it totally worked and it really eased the process of installing the replacement seat cover. Thanks!


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[minimo]

The front brake was a mess so I decided to rebuild the master cylinder and front brake caliper. I also honed the inside of the m/c cup while poking out the tiny holes with thin guitar string and blew out the passages with carb cleaner. Did the same for the front brake caliper. The hoses looked to be in good outward condition so I poked out the insides with some thin baling wire and a generous amount of PB Blaster to clear out the peanutbuttery-looking gunk from the inner walls.

New is always nice. This is an aftermarket brake piston from 4into1.com which I’ve purchased before for a couple of other bikes and they are good - oh, and don’t forget to replace the seal too

Master cylinder rebuild kit was also an aftermarket purchased from 4into1.com

Master cylinder rebuilds keep getting easier and faster for me, and it really could not be possible without my trusty Motion Pro snap ring pliers. I love these things. It was one of those “should I really spend money on these” kind of items but boy am I happy I did. Recommended purchase.

How else could you contend with this kind of mess?


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[strynboen]

mine air test gave a bit low fuel nievo in the bowls.so intresting to see if yours give the same resultat..my teori is that ve need to give it 1 mm less in gap..use the dry metode...(the flots sink a bit in the fuel before they float.. to kompensate..for that..so instead of 14 ve gibe it 13 gab messuring..to heighten the fuel level


.but i have the new type carbs..a bit strange you have the old type on a 77..but that can be a f bike thing...the older carbs is easyer and run a bit better..but have not the nice hand cnop cabel choker...vho can adjust the idel..nice on a Cold engine.if it runs a bit lean

[flatlander]

seat looks good, nice trick with the tack strips. where did you get the cover?

[WhyNot2]

scribed to hear more about the carb testing

[Stev-o]

That MC was nasty!

[minimo]

Thanks, everybody.

Flatlander, here’s where I purchased the seat cover:
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F262356579922
Not bad for $35 (plus shipping). Quick shipment too (from Tampa to LA).


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[minimo]

the older carbs is easyer and run a bit better..but have not the nice hand cnop cabel choker...vho can adjust the idel..nice on a Cold engine.if it runs a bit lean

Sadly, that large idle adjust knob was grossly bent and I tried bending it back without heat and it snapped off :-(

Maybe I will have Jim French http://www.jmfmicroweld.com take a look to see if he can do his magic to make it come back together. Jim French is the man to reach if you need any tiny aluminum bits welded, like float towers on the carbs that can snap off, well, Jim can fix that. Be sure to send him the float and the pin too so he can test fit it


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[flatlander]

Flatlander, here’s where I purchased the seat cover:
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F262356579922
Not bad for $35 (plus shipping). Quick shipment too (from Tampa to LA).

thanks! looks like a good repro of the original, even has the logo. the vinyl is black not dark brown, right?

[minimo]

Yes, mine is a black. They do also have brown options. I liked that they had the Honda logo on there too; sealed the deal for me.

Ebay seller: hondasvintage

They have so many other vintage seat covers (with logos printed on them too!)


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[flatlander]

brown ones (for 550 f1) are very rare. good to know they have them.

[SOHC4 Cafe Racer Fan]

Looking at the tank, I wonder if you could use paintless dent repair to get the ding out, and then polish the bejeezus out of it to see if the paint will come back (or have some nice patina on it).

[minimo]

Yeah, if I get this motor runnin’, I think PDR on the tank would be great and definitely worthwhile. Thanks.

Meanwhile, I got the front brake all installed. I miss the days of my Speed Bleeder - will consider getting one for this bike maybe once I get it running. I’ll be rebuilding the front forks (new seals and oil) so this’ll all be coming apart again anyway.

Meanwhile, getting the carbs on this stock setup sucks. Makes me appreciate air pod filters completely. After some head scratching, I figured the best way I could get the stock carb and airbox system all connected was to first get the intake manifold loosely in place sans the rubber boots (pulling the boots off is the key), muscle the carb rack on, and then pinch/fidget the rubber boots back on, working from the middle two and out.
What a pain in the arse it’s gonna be when I have to pull the carbs off again for any adjustments.


I’m missing the oval-shaped spacers (they kinda look like large-sized crimps) and the rubber bushings for the seat lock thingy. Are parts for these still available? A whole new kits runs around $20 - not going that route.



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[strynboen]

i use to heat all rubber use the heat gun.
.Mount the airbox.
.move the carb bank from dovn back......up to the intakes......and then press forvard and up..at same time..and NOt try to get the airbox fit.
.as the carbs get right on the intake studs..i then easy "svup "the airbox studs.. in the carbs..all my rubber is soft and easy going..it take a few minuts to do the "svup"...i have the new type carbs..think it is easyer to do them..


can you not use those elektric rubber isolators..for viring through Sharp plates...and cut a small tube as inner lining...somthing like you use at the rear light isolators/vibrasion dampers..in danisk ve call then ..."gummi tyller"-lednings gennemføringer..

[minimo]

Took a trip to my local Lowe’s hardware store, which was sad and empty because of NYE, but it allowed me full reign over the hardware drawers and I was able to find some rubber grommets and collar standoffs to make my seat lock thingy stay on for now:


I did have to take the collar (there was only one in the package) and chop it off with my cut-off wheel. This whole fix set me back about $3. Woo hoo!


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[MauiK3]

Cool project, funny how we go into these things and they take on a life of their own. Before you know it you'll have a very clean 550 to cruise around with!

[minimo]

Thanks, MauiK3. I’m definitely putting in some time and a lot of elbow grease into this bike that we don’t know for sure runs yet... But we are definitely getting somewhere.

I spent a good part of today giving attention to my exhaust. Here’s a chronology of how that all went down:

Essentially, I made a silicone gasket material sandwich out of some shiny plumbing pipe.

Went to Home Depot and picked up a shiny pipe that was close to the diameter of the exhaust pipe

Next, I got my angle grinder with a cut-off wheel and chopped up the pipe. One piece to fit inside the exhaust and one more that was larger, covering the hole on the outside

I clamped both strips together and drilled 1/8” holes on the ends and lined that over the top of the exhaust to make sure those holes all correspond to receive an 1/8” aluminum rivet. Light scuffing on the mating surfaces of the pipe strips was done to ensure a decent mechanical bond. I then smeared some high-temp silicone gasket material inside and around the hole

and then fished the thinner strip inside and kept that in place with a couple of tiny drill bits, smearing more and more of the gasket material over top (acetoxy and these household-type silicones are condensation cure-based so they’re not easily inhibited by other chemicals and cure relatively quickly at room temp and multiple layers can be coated)

After allowing this to dry for a bit, I gooped on more silicone material over the area and on the inside of the larger strip, squished that pipe cover on and quickly riveted the layers together while still wet

I decided to cover another tiny hole using only a thumbnail of the plumbing pipe and smeared some gasket material on and riveted it on just the same. While allowing this all to dry, other areas cleaned up easy with acetone.
I’m fairly confident this will all hold at least for a little while and the repair, which thank goodness is on the bottom is not too obtrusive. Whether the silicone gasket material will hold to the rust on the inside, well, that’s why the sandwich with the two strips and hopefully there’s enough tension on it preventing any of the exhaust pressure to escape. Fingers crossed this works at least well enough to get it going for a little while.
Here are some horrible nighttime photos, well, because it got dark


Luckily the Holiday has allowed me some time to get a little creative with these repairs, besides I want to minimize my spending on this project especially since I don’t know yet if it’s going to run. Getting closer and closer to kickstart. Stay tuned...



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