Topic: 1974 CB550. Racetech Monoshock. JMR Head. Built Engine. "BLAC"

[Denver_Larry]

If I can put my 2 cents in here on your quick and dirty photoshop mockup:

Consider making the new hoop that runs over the tire (from the original shock mount locations) a bit snugger to the tire than you have shown.  And possible using a longer support tube from the swingarm pivot area.  These both will help with the geometry, as it is now you will have a falling rate setup instead of a mostly linear or rising rate setup.  Or get the front end of the shock lower...

[BLAC]

I have to commend you. Despite the multitude of folks who chase an aesthetic and don't give much through-thought, you on the other hand have mocked, photoshopped, analyzed, and now are prepared to have professionals perform the critical calculations. Its really great to see someone update these bikes "properly" and get what the want out of it. I doubt this will fall into the "Started, never finished" bin due to lack of commitment.

You will invest far more than the market for this bike will return. BUT, you will have a truly custom bike, that you built, that can be bought, no one else has, and it will still be a blast to own/operate and cheap to repair in 20 years. If I had a hat on, I'd remove it for you-

Thanks, cal I really appreciate it!  I figure that if I'm going to do it might as well do it right!  And there are people way smarter than I am, so might as well pick their brains.

If it's no fun to ride, I have wasted a lot of money 

[Retro Rocket]

I have to commend you. Despite the multitude of folks who chase an aesthetic and don't give much through-thought, you on the other hand have mocked, photoshopped, analyzed, and now are prepared to have professionals perform the critical calculations. Its really great to see someone update these bikes "properly" and get what the want out of it. I doubt this will fall into the "Started, never finished" bin due to lack of commitment.

+1
Thats the exact reason I commented here Cal, There's very few here that actually do it right when performing these type of mods   

[RAFster122s]

I'm looking at the photoshop mock up and if I think about the arc of travel for the swingarm would it translate into the motion needed?  It arcs forward and then down, right?  But, I haven't really looked at monoshocks, so, maybe I haven't considered it enough or studied them at all.  So, never mind.

I think that Godfrey's monoshock conversion would be worth looking at...  He has some very nice builds documented on his site.

[BLAC]

I'm back from the dead! It has been a few crazy months at work and I am just coming of 25 days straight on the road... The good news is I have made some more progress on the bike!

I bent a hoop out of 1" chromoly, and then decided to chop off and file down the stock mounting points from the swing arm and slot the "hoop bar" so it can sit recessed in there to look clean/stock once finished. 

Now on to the pics...

Milling the channels in the hoop.


Added the front brace bar (I'm finally getting decent at fish-mouthing!)


Test fitting... Getting Closer...


Ahh there it is.


Mock up.


Looking good for now!


The one thing I don't like about the lines of my bike is the Joker Machine brake strap.. Is there a way to remove that, rotate the drum a bit and mount the tab to the swing arm or the hoop bar I made (or any number of possible mount points)?

[calj737]

Wait until you mock up with the exhaust, it may disappear behind it. If not, perhaps anodize or powder coat it in black. A hole saw makes fish mouths very accurate and easy. 

[540nova]

A hole saw makes fish mouths very accurate and easy. 

+1 it's what I always use. Tubing notchers are pretty inexpensive.



1974 CB450, 2006 CBR1000RR

[BLAC]

There must be a reason that the drum brace bar is so long and attached up at the front of the swing arm, is it to limit the twisting of the swing arm when heavy braking is applied?  Im just wondering why it isn't anchored to the swing arm much closer to the mounting point?

[calj737]

I think it has more to do with finding a secure point in the same plane than anything else. Also, there's far less movement from the mount point on the pivot tube then there would be if the brace were attached to the leg, which moves vertically constantly. Granted, it should only move relative to the wheel hub, but movement introduces weakness and the potential for instability.

[luvmy71]

Just started reading your thread.  Great job!  I just started a 550 build (first build for me) from a frame and engine so this along with several other 550 threads and the input from the great members here are going to be extremely helpful.

Did I see an Oregon Ducks Fiesta Bowl t-shirt somewhere along the way?   Go Ducks!!!  Class of '81 when it was painful.

I live right down the 5 in San Diego.  Would love to connect with all the LA board members sometime when there is a fun event.

Keep up the good work!

Kevin

[SOHC4 Cafe Racer Fan]

blacSOHC,

This is looking great!

[BLAC]

Did I see an Oregon Ducks Fiesta Bowl t-shirt somewhere along the way?   Go Ducks!!!  Class of '81 when it was painful.

I live right down the 5 in San Diego.  Would love to connect with all the LA board members sometime when there is a fun event.

Kevin

Heck ya!  I was actually born in San Diego but I grew up in Eugene.  I have 6 aunts and uncles who went to Oregon, my mom works for the school and my cousin played as a back up wide receiver for them 3 years ago... Needless to say, I bleed green

[BLAC]

blacSOHC,

This is looking great!

Thank you!  It has been a ton of nitty gritty work, but overall its coming together nicely (I think)

Here is another photochop of the bike with a spring


I am liking all the angles in the rear, I used the same dimension (different size and flipped) triangle to keep all of the angles in a similar family, I think it is looking intentional at least lol

[Camrector]

Looking great. I'd paint that brake stay black as well. You'll have another "angle" running through there with the push rod.

[riverfever]

I haven't been around much since school started up. Glad to see you're still plugging away. Bike's really looking super man. Really impressed with what you're doing. Keep at it.

[BLAC]

I haven't been around much since school started up. Glad to see you're still plugging away. Bike's really looking super man. Really impressed with what you're doing. Keep at it.

Thanks I appreciate it!  Getting the monoshock ordered and mounts fabbed will be the next time suck on the roadmap.  I have been to NY 3 times this month on business, so shop time has been slim.  Once I get the shock in, I will toss the motor back in it and get it all mocked up so I can make sure the tabs I think I want to cut off the frame are actually unused and then its time for disassembly, powdercoat, and then trying to figure out how it all goes back together =)
 

[BLAC]

A little update:

I have been making slow and steady progress that I will update this thread with once I get a little free time, but for now I will just share this piece I got from Cliff =)

[bill440cars]

        Just got into this thread and this is some kind of cool build, with lots of great input. I will be checking for updates on this one. I am one of those who would like to see those as nice as this, be restored, but I am really liking the thought put into this, and after all, he who provides the bucks, has final say, right? I'm subscribed brother, build on. 

[540nova]

I've never seen wheel weights like that, home made?


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[SOHC4 Cafe Racer Fan]

Nice fender.  How are you planning to mount it? 

[Stev-o]

Nice fender.  How are you planning to mount it? 

+1.  And polish it to match fork lowers?

[BLAC]

Nice fender.  How are you planning to mount it? 

+1.  And polish it to match fork lowers?

I drilled out the rivets on the stock fender and am looking at lowering the side risers to bring it in tighter to the tire or make a custom 'bracket strap'.  I made a template out of cardboard that should work, i just need to make sure that the asymmetry of the brake side is bent and shaped right.. it wont be easy, but I think I will be able to fab up something (hopefully out of aluminum so I can weld directly to it on the inside) that will work.

Yes Im planning on polishing it to match the fork lowers, and maybe to a pinstripe of color around the crease to pop some color, once I figure out the pant scheme..

[BLAC]

I've never seen wheel weights like that, home made?


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I have the wheels laced by Buchannan's and I guess that is the 'period correct' style? not sure but I am told it works haha

[BLAC]

        Just got into this thread and this is some kind of cool build, with lots of great input. I will be checking for updates on this one. I am one of those who would like to see those as nice as this, be restored, but I am really liking the thought put into this, and after all, he who provides the bucks, has final say, right? I'm subscribed brother, build on. 

Thanks for the kind words!  I totally understand where you are coming from regarding the originality.  This is my first time getting into a CB and I really wanted to see how things went together as a whole unit.  If I do another one in the future I will start from a bare frame (and all of the learning from this build  )

I am investing a lot of time and money into it, once it's done my goal is for it to be a 'well executed' build.  I know style is subjective and isn't going to make everyone do backflips, but I'm doing my best not to cut any corners and really do it the right way.

Next step is to have RaceTech make my custom rear spring... anyone have $900 I can borrow?   

[calj737]

.. it wont be easy, but I think I will be able to fab up something (hopefully out of aluminum so I can weld directly to it on the inside) that will work.

Be mindful that if you weld something underneath you are moving the fender further away from the wheel. Not much since you're planning to use flat stock, but some.

Consider coming over top of the fender with round stock and then down. Using aluminum, you can then flatten the end (heat and squash) to drill mounting holes for attaching to the fender. It may also prove easier to persuade the mounting offsets from each side.

If you check out Devin's IG account, you can see a nice shot of one of their test bikes with the fender fitted and tucked up tightly to the tire. Looks very sexy-

Yes Im planning on polishing it to match the fork lowers, and maybe to a pinstripe of color around the crease to pop some color, once I figure out the pant scheme..

If you polish the fender, your paint won't stick. So wherever you want to paint will need a decent scuffing up. Maybe consider anodizing the fender? Or have just the  edging powder coated? Then you can polish the interior? Or paint/powder the entire fender then remove the crease only and polish it up (polished stripe, painted fender).