Topic: My uncles 78 CB550K. New restoration

[Stev-o]

Unfortunately, I'm in Durango at the moment (observing the yellow river!) and don't have access to the pipes, but will take more shots when I get home.

Is "observing the yellow river" a euphemism for something?

Good question.  I've been to Durango, nice town, don't remember a yellow river. 

[MoMo]

Unfortunately, I'm in Durango at the moment (observing the yellow river!) and don't have access to the pipes, but will take more shots when I get home.

Is "observing the yellow river" a euphemism for something?

Good question.  I've been to Durango, nice town, don't remember a yellow river. 

Maybe he was pissing when responding..(but that'd be another thread, wouldn't it?)

[SohRon]

Not to hijack the thread, but yeah, Stev-o,  I do have quite a selection of parts left over from the build; some good, some bad and some definitely ugly. If I were heading for Texas I'd toss it all in the back of the van and dump it on your doorstep. Let me know what you're looking for. Same applies to you, Turbo, and anyone else looking for 550 parts.

"Yellow river" refers to a mining spill on the Animas. Don't you guys ever listen to the news?  Google "Durango yellow river" to catch up with the rest of us! 

[Turbogrimace]

hahahaha.  fun stuff.  I need an exhaust and a good 77/78K rear fender.  Everything else I might have coming from another forum member. 

I do need some small stuff like the top triple clamp bolts for the forks, lower rear engine bolt and passenger pegs.

[Turbogrimace]

I've been pondering what to do about the wheels nonstop. My friend has a nice set of cb750A aluminum rims and I'm considering saving a few bucks and lacing those to the stock hubs. What affect would reducing the rear wheel to 17" do to the dynamics of the bike? 17/19 vs 18/19.

Im pretty sure without looking that the rolling diameter would decrease. Bit this might be a good thing because newer tires are much taller than they were in '78. It might cancel out. But the front will be a tad taller too. I'm going with roadriders near stock size.  In terms of changes in the handling characteristics, I just want any change to be minimal or a net positive.

[seanbarney41]

I've been pondering what to do about the wheels nonstop. My friend has a nice set of cb750A aluminum rims and I'm considering saving a few bucks and lacing those to the stock hubs. What affect would reducing the rear wheel to 17" do to the dynamics of the bike? 17/19 vs 18/19.

Im pretty sure without looking that the rolling diameter would decrease. Bit this might be a good thing because newer tires are much taller than they were in '78. It might cancel out. But the front will be a tad taller too. I'm going with roadriders near stock size.  In terms of changes in the handling characteristics, I just want any change to be minimal or a net positive.

17" tires can be had in profiles near to the diameter of a standard 18", make up the difference with longer rear shocks...the lighter aluminum rims are worth any negligible drawbacks imo

[calj737]

While a drop in circumference will change the geometry mathematically, it is very likely that you can not ride that difference on public roads. Much is hashed on about rake and trail changes on this forum, and while it's accurate completely, I also contend that 99% of the riders will not be ill-effected. Either they simply don't pilot their bikes with such vigor to detect the changes, or, they're too inexperienced a river to utilize the changes.

Track bikes and road racers likely might see it on a public road, definitely on a track, but a citizen motorcycles on public roads? I'm not persuaded. Add to that the variable of solo riding, two-up riding, even toting some gear, all of these things greatly effect the handling far more than 10mm of circumference can.

Install the 17" and buy two good tires. Then ride on!

[MoMo]

While a drop in circumference will change the geometry mathematically, it is very likely that you can not ride that difference on public roads. Much is hashed on about rake and trail changes on this forum, and while it's accurate completely, I also contend that 99% of the riders will not be ill-effected. Either they simply don't pilot their bikes with such vigor to detect the changes, or, they're too inexperienced a river to utilize the changes.

Track bikes and road racers likely might see it on a public road, definitely on a track, but a citizen motorcycles on public roads? I'm not persuaded. Add to that the variable of solo riding, two-up riding, even toting some gear, all of these things greatly effect the handling far more than 10mm of circumference can.

Install the 17" and buy two good tires. Then ride on!

agree with cal's assessment that a large percentage of riders would not feel much difference(know I would fit in there)...Larry

[Turbogrimace]

I totally agree and I know that I'm overthinking it relative to how the bike will be used 95% of the time. I'm just trying to preserve the original feel of the bike.  I've had everything from stock rake/trail to 40* rake/9" trail to 56* rake/3" trail.  Those last two were fun. For a custom bike, build it with sound geometry and learn to ride it.

Im curious about diameter changes because I've read a few threads about racers preferring 18/18 rims, and some preferring 17/19 and 18/19.  Im not sure why though.

Finding spokes is going to be the hard part.  Buchanons doesn't have the specs for 77/78 CB550 rear spoke heads, so I have to send some in for measurement.  The spoke flange on the rear hub was wider for 77/78.  Add to that the 17" rim.  mmm time for custom spokes again.

has anyone ordered buchanon's spokes for a 77/78 CB550K?  If so, I can get your name and they can pull up the measurements.

[Turbogrimace]

Finished the resto several months ago.  Last December everything but paint was done.  I finally got the paint complete in the spring.  Thanks for all the help guys.  and a big thanks to Sohron for the must have exhaust system!

Theres a shot of my uncle sitting on the bike.  He hadn't been on it since 1986 and was through the roof to see it back on the road.  My son helped with a lot of the work, including carb rebuild, restoring the pegs, cleaning, and changing up the suspension.  This was my first resto and it was a very different experience compared to building a custom bike.  It was like putting a scale model together aside from punching out the plastic parts. 

















I took it down to north Carolina for the Honda chopper meet with the stock suspension to learn the stock feel.  Immediately after, I added 15 wt to the front and put on a set of 75/120 progressive shocks I got for the amazing price of free.  Since the rear shocks were 0.75" longer, and I didn't like the twitchy feel of the front end at high speeds prior to putting them on (everything was tight), I also added a steering stabilizer with a stainless bracket.  These three modifications completely transformed the feel of the bike.  The suspension responds well, feels balanced front to rear, and the steering is incredibly smooth.  No more pogo-ing or sinking around corners.  I absolutely love this bike.  Unfortunately during the rebuild, my uncle developed a hip problem and cant ride at the moment.  Hopefully he'll heal up and can take it for a spin.

Once again, thanks to all the board members who offer up advice, support, "constructive" harassment, etc.  I'm glad theres another one back up on the road.

[Pan1cReaper]

Awesome story and he bike turned out great. Good job man.