Topic: 75 CB550 Pull-Shock Cafe

[Mypenname]

I have been working on my 75 CB550 that I picked up a few years ago and I thought I would share some of the work I have been doing. I have been wanting to do a cafe project for some time so this is my first bike project.
I am doing a few modification to the suspension and frame.

The bike was a basket case with a non-running engine and two baskets of parts.










The front forks were pooched



Started disassembly



Picked up a front off a GSXR and 19" tire off a Harley



New bearings were needed to fit the GSXR shaft.



I found a used pull-shock off a Buell



Cleaning up the shock



Powder coating the spring

Looks better


Time to work in shock mounts

Mocking up

Using some EMT for mock up




Needed a pipe bender so I picked this up.



Making some test pieces but I need to clear the header.



So I made it out of sections to get the tight bends I needed to clear the header





Front mount tacked on.









Time for the rear mount

Mocking up



Made some end links for the rear mount




Made some mounting tabs for the shock



Bent the hoop and welded on the end links



Rear swing arm done





Next will be working on the frame modifications

[tshrey]

That is fantastic work.  I haven't seen anyone do that.

[palepainter]

Really nice!!!

[SOHC4 Cafe Racer Fan]

Very nice fab work.  I have not seen a underframe monoshock suspension on a CB until now. 

Curious, how did you determine the correct spring for the bike, since there's a weight difference between the Buell and the 550 and the frame geometry is probably different, too?

[sinister902]

some nice lines developing here, will be interested to see where you take this.

[Mypenname]

Thanks for the compliments
 
I have studied a CB550 that was done by Old Empire Motorcycles that used a pull shock.
http://www.pipeburn.com/home/2015/09/25/honda-cb550-old-empire-motorcycles.html

I worked on the geometry for the rear swing arm link until I found a spring rate that I was happy with.

Here is a short clip of a pull-shock in motion.

[SOHC4 Cafe Racer Fan]

Unfortunately, many garage builders slap a shock that they think will fill a space, but with no mind for squat/anti-squat, suspension travel, etc.  It's more the exception to the rule that do it right.  For instance, BLAC went to Racetech and had them look over his monoshock construction and Racetech then built him a bespoke shock.  Can you give us a Cliff Notes version of what you did to come up with the right shock.  Maybe you can help either demystify the process or (alternatively) let people know what kind of math is needed.  Thanks.

[Mypenname]

SOHC4 Cafe Racer Fan: The pull shock that  I am using is from a 95 Buell and even though it does contain some adjustments and different spring rates are still available for this shock, I wont have a true idea on it performance until I am able to do some actual field testing.   

[Mypenname]

I did some more work on the rear of the bike on the weekend.

A little trimming of the frame. 



Cleaning up were the two frame tubes meet.



Bent some tube and filled in the area where the two frame tubes met at the swing arm
 


Made a rear hoop for the seat and lights.



Made up an aluminum battery box



Rolled a piece of tube for the uprights that will follow the contour of the rear tire.



Up rights fitted and tacked into place. I also made an aluminum cover for the battery box, The opening for the chain still needs to be adjusted.





Starting to work on the rear cowl and seat.

[SOHC4 Cafe Racer Fan]

The new subframe looks very nice and clean.  I hope the pull shock works out without too much brain damage.  For a first bike build, you definitely have some metal fab skills.  Also, have you thought of a shield for the shock to protect it from road grime, dirt, etc. getting in the shock?

[GV1390]

A friend of mine recommended me doing this a few months back and I thought it would be radical.....awesome seeing one done on a CB550! Haven't seen that before. Keep up the good work, those are indeed some impressive fabrication skills.

 

[SOHC4 Cafe Racer Fan]

The work on the subframe and swingarm looks good. I assume you used a jig of some sort to keep it all square.  (FYI - my posts are more for the benefit of others -- so you can share some expertise and knowledge before they cut their frames willy nillly).

[Darren Jakal]

That is some fantastic work!

FYI, I have seen another 550 pull shock by Old Empire Motorcycles. I always wanted to see their front shock mount, but no real decent pics of it.

Look forward to more,

cheers, dj

[Mypenname]

SOHC4 Cafe Racer Fan, That is a good point, it is very important that you have a very well established datum line. Brace, measure and remeasure. Make sure you are very careful when doing any cutting that things are not going to move. The changes that I have made to the main frame are just tacked in place so when I go to do the final welding I am able to mount it firmly to my welding table and brace it so that I don't end with a pretzel for a frame.

The rear swing arm was securely mounted to my welding table when I did the final welding.


Darren Jakal, The Ripon cb550 from Old Empire Motorcycles was my inspiration for the suspension. 

[SOHC4 Cafe Racer Fan]

Mypenname,

Although your thread is titled "First bike build," you definitely have some fabrication expertise.  Can you share a little back story as to your background, skillset, and what else you've built?

[tshrey]

There a reason you chose to kick the subframe upwards instead of staying on the bottom of the tank line?

[SOHC4 Cafe Racer Fan]

There a reason you chose to kick the subframe upwards instead of staying on the bottom of the tank line?

It looks like he pretty much DID keep the subframe level with the bottom of the tank line, until the rear-most portion FOR SUSPENSIONTRAVEL/TIRE CLEARANCE.

[tshrey]

There a reason you chose to kick the subframe upwards instead of staying on the bottom of the tank line?

It looks like he pretty much DID keep the subframe level with the bottom of the tank line, until the rear-most portion FOR SUSPENSIONTRAVEL/TIRE CLEARANCE.

I guess I disagree with your definition of a line, no need to shout.

[SOHC4 Cafe Racer Fan]

There a reason you chose to kick the subframe upwards instead of staying on the bottom of the tank line?

It looks like he pretty much DID keep the subframe level with the bottom of the tank line, until the rear-most portion FOR SUSPENSIONTRAVEL/TIRE CLEARANCE.

I guess I disagree with your definition of a line, no need to shout.

All caps can mean emphasis and not necessarily shouting.  Thanks for posting the photo with the line extended -- it definitely makes your point more compelling. 

[Mypenname]

Easter weekend not alot of time to work on the bike.

I took her outside in the sun for the first time in over a year. She is looking a little pail.





I also was not totally happy with angle the rear seat so I have been playing with the design. I want to still have room under the rear light for the plate.

[Medyo Bastos]

That stance is great. Would a side mount work for your plate?


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[tshrey]

Looks so clean above the swingarm without any suspension components!

[Mypenname]

Medyo Bastos; I might look at the side mount for the plate but i do not think it is legal in Ontario

tshrey; I am trying to keep it clean and uncluttered.


Made up some mounts for the the rear sets tonight. I wanted them easily removable just incase I wanted to move the rear set location.

[Mypenname]

Did some more work on the CB this afternoon. Modified the rear sets and made new linkage for the shifting arm. Modifying the rear brake rear-set is next.

[tshrey]

What is that linkage connected to?

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