rear seat loop on a cb550

[nemo]

I want to weld a rear seat loop to my 74 cb550 like the one from DCC

My concern is that if i cut the frame off after the shock mounts the frame isn't exactly a perfect circle, so the loop wont match up and look good. I was wondering if any of you guys with a bike like this have already delt with this. Thanks for the help

 

[Mad Ratter]

Hi, I had same prob with my GS550 frame, cut off just behind the shocks. I got two pieces of ready bent tube (exhaust bends from a muffler shop) and welded them together to ensure it matched, is that what you mean? trouble was I could only find some that had a slight straight, so its not a perfect semi-circle but its a loop! Its 25mm tube and I used some 22mm from some old handle bars to use as spigots inside to line up and add strength, cut the inner tubes at the top halfway down and bend them up to give the loop a bit of a "lift"

 

[Clinedesign]

Mad Ratter, do you have a project build we could look at?

 

[Mad Ratter]

I'm right in the middle of the shitty part, degreasing engine etc etc, ya know the kind of stuff. Iin the middle of carb rebuilding too (what a mission!) will put some photos up with a new thread when I get chance and when the bulk work is done, have been taking photos right through so nothing is missed

 

[550 Okie]

I know this post has been dormant for a while, but I thought I'd reply anyway. I'm new to the board and came here looking for more thoughts on this same issue. Here's what I've found in all of my searching: a cb550 tail mod by Holiday Customs http://holidaycustoms.blogspot.com/2012/01/weekend-chop.html

As you can see, he just cut some sheet metal into a shield-like shap and bent up the sides to go blend with that extra metal. I hope this helps, but I'm sure you've already found some solution to this by now. If so, post a picture and let me know how it turned out

 

[MotoMadness]

A bit more work but this is what we did on the CB350 Stamped Steel frame. Shock mounts still need to be welded on and the front part will be made seamless. We can make the half or full loops too.

 

[TurdFurguson]

Mothgils did exactly what you are wanting to do on his 550, and we did it on my 100. If you sleave it out so the tube connects inside the frame, not just welded onto it then your going to have more strength and you can pull your frame straight with it. Here is a link to his project thread

http://www.dotheton.com/forum/index.php?topic=13680.10

Here's my 100 and how we did it (little better pics of the process)

http://www.dotheton.com/forum/index.php?topic=30330.90

 

[teazer]

Nemo, You are spot on. All the shop offs leave an ugly scar and open steel stampings and only a few have been finished nicely. In many cases the parts cut off could have been hidden within the seat, but that's not always the case. Flat hoops are the worst from a perspective of tire-frame clearance, so we always use an up-tilted loop if we fit one and it's rare for us to fit a loop at all. The frame has to be braced but it can be inside the seat and hidden. There is no need to have a loop hanging out the back from a stiffness perspective.

A loop does provide a convenient place to hang a fender or tail lamp and license plate, but with LED lights and sportbike license plate brackets, they can hang off a fiberglass seat without and drama.

When are seats with integrated plates and lamp mounts going to make a comeback?

Matt Ratter's is arguably the most appropriate and neatest loop on the page, but it's also very short.

Someone must have boxed in the steel stampings or modified the stampings to close the gap.

 

[J-Rod10]

Here's my 500. Cut the frame, bent a loop, welded a fender/tail light mount to it, and it to the frame. Then welded mounting tabs to the bottom of the frame for blinkers. On some of the newer stuff I'm doing, I'm capping the frame after cutting it, and before welding the loop on. Gets rid of it just looking like a hollow tube.