Topic: 73 racer build

[Jhelgesen]

Hi Guys, wanted to share my project with the group, and see what the collective knowledge base thinks.

I have a 73 cb550 that was in storage for a few decades (actually had a pair of them, and took one back to stock), using this as my starting point.



I have the engine running and carbs cleaned out, electrical system in good shape. 

From there, the deconstruction happened.  Added the CX tank and the sport wheels I wanted.  I wanted to keep the rear drum brake, so I'm using cb750A wheels.  Gave me a 2.5" wide rear rim    Swapped on the cbr600rr front end.



Using my handy dandy 3d printer, sampled the spacers needed to adapt the brakes to the wheel.

Question for the group, should the axle be slightly shorter than the spacers and stack up, to put the assembly in compression when tightened?





Made the frame changes I wanted in the rear, and did some stitch welding on the front to stiffen it up.  Then got her outside for some pics.

[Ravie]

Very cool. I'm trying to use that same tank on my CB750 build and I think I finally came up with a good mounting system. I just need to get a few bolts welded in place to mount the rear, and the front I need to weld in some extensions to fit the narrower mounts.


I LOVE those wheels.

[Jhelgesen]

The space under that tank is HUGE!

I'll probably be able to mount all the electrics, a battery, and the kitchen sink under there.

[SF]

I like the direction your going

[goldarrow]

looks like you have a 74 550, if 73 - it would be a 500.  those gold inverted forks look so pretty.  if stock pipes are not rusted out with holes, i'm interested.

[calj737]

looks like you have a 74 550, if 73 - it would be a 500.  those gold inverted forks look so pretty.  if stock pipes are not rusted out with holes, i'm interested.

May be a 500 frame but it's definitely a 550 motor. Side covers tell the story-

[Jhelgesen]

ID tag has a 73 build date and says CB550, probably an error on the title that says its a 73, but I'm not gonna fuss with the SC DMV over it

[goldarrow]

ID tag has a 73 build date and says CB550, probably an error on the title that says its a 73, but I'm not gonna fuss with the SC DMV over it

if build date stamped on the neck is around second half of 73, then it's 74.  it's good idea to know the correct year for the bike, just in case you ever need to consult parts fiche for certain motor/frame parts, and true that DMV won't care much to what you have, as long as appropriate fees are paid

[Ravie]

Reminds me of the title I have for my bike. When they guy I bought mine from got a reprint, they entered the VIN wrong and it's missing a digit. I think I'm going to ignore it for the sheer BS I'd probably have to go through to get it corrected. It'll be right on my Insurance, anyway.

[Jhelgesen]

looks like you have a 74 550, if 73 - it would be a 500.  those gold inverted forks look so pretty.  if stock pipes are not rusted out with holes, i'm interested.

Two sets of stock pipes were patched together to make the one good set for the stock bike.  I've still got the remaining front halves of the exhaust though.  Check out those bars on the right hand bike, waaaaay cool.....not.

[SOHC4 Cafe Racer Fan]

Those bars are hilarious.  Thanks for posting up a new thread.  This is a great start.  The CX tank rides a little on the high side.  I wonder if you can modify the "c" mounts to let it sit a little lower and keep a flatter line flowing through the bike.  I was curious as to where you harvested the reverse comstars (from your post in Rusty Olive/Cameron's thread), so thanks.  Looking forward to how this turns out.

[Jhelgesen]

On the tank, yeah, its a bit high still. 

I've ground down the seam on the frame and rewelded it, along with some hammer work on the bottom of the tank.  I may try and form a small skirt around the bottom seam of the tank to try to flatten it to the lines of that I want, that and more hammering.

[calj737]

ID tag has a 73 build date and says CB550, probably an error on the title that says its a 73, but I'm not gonna fuss with the SC DMV over it

Disregard the build date and look at the VIN #. It will contain the model size within it.

[RobbyD]

Damn, great start man.  Keep up the good work

[quebec_monstro]

Wow really interesting I'll be following up that thraed...keep up the good work 

[vfourfreak]

These CBs look great with USD forks and modern brakes. Sort of indicates where Honda mght well have taken them if they continued their development beyond the early 80s.


Kev

[Jhelgesen]

Started a few sale threads to make space and gain some working funds.

http://forums.sohc4.net/index.php?topic=140213.0
http://forums.sohc4.net/index.php?topic=140181.msg1587551#msg1587551

Got the chain geometry in good shape to measure for spacers.  Won't need offset sprockets after all.



Pulled the filler cap from an otherwise banged up tank to replace the boring one on the cx tank.

[Jhelgesen]

Got my MotoGPworks SS exhaust this Saturday.  I have to say it a piece of art.  Can't wait to hear it.

Bike is back on the stand, started playing with changing the lines of the bottom of the tank.

[SOHC4 Cafe Racer Fan]

I like how this is coming together.  That CX500 tank is growing on me.

Don't forget to weld a hanger for your MGP pipe.  It will keep that weight off the head exhaust ports.

[Jhelgesen]

My day job sends me to China a few times a year, so my last trip, I get a buddy to give me a hand hunting parts on their equivalent to ebay.  Brought home some new parts, cb600 fender, shocks, two sets of clip ons, cnc levers, various brake parts, etc.  With shipping the damage was under $200US and it all fit in my suitcase. 

[brandEn]

Your off to a good start. I like the front end conversion.

[jgreen]

Excellent build thread.  What type(s) of modifications, if any did you have to make to the steering stem and/or bearings to do the fork swap?

Thanks.

[Jhelgesen]

Excellent build thread.  What type(s) of modifications, if any did you have to make to the steering stem and/or bearings to do the fork swap?

Thanks.

None, its a direct bolt in

I will need to trim the steering stops on the frame to gain a hair more travel.

[seed608]

I like the progress, did you do anything to the rear shocks? I have read that some guys rebuild them out of the box


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[Jhelgesen]

Nothing done to the rear shocks except bolt them on so far.  Looking at a longer set to pick up on my next trip, raise the rear just a hair more.