Topic: Throw out your “cafe line diagrams”, cb550 bobber

[work9to5]

I'm liking where you're at with this build. I hope to go the same route with my next one.

Thank you DV, I appreciate the thumbs up. The 70’s chop n’ bob look have been growing for a a couple years now, but I’ll admit I’m a bit crazy to do it to a cb550 in In the end, I’m building it for myself and that’s all that matters, that I like it. But positive input helps thanks.

Progress- having some difficulty with the wiring. I’m getting a -2 volt drop in battery power as soon as I connect a freshly charged battery. I basicly get 3 three solid cranks of the starter before the battery goes to >12.5 volts and then she won’t start. It’s frustrating. Not understanding why 12.5 isn’t enough to start. Have swapped battery’s, swapped in a different starter still no difference. Considering I don’t have any other draw (tail light, headlight are not wired in yet).

[work9to5]

I'm liking where you're at with this build. I hope to go the same route with my next one.

I'm liking where you're at with this build. I hope to go the same route with my next one.

Thank you DV, I appreciate the thumbs up. The 70’s chop n’ bob look have been growing for a a couple years now, but I’ll admit I’m a bit crazy to do it to a cb550 in In the end, I’m building it for myself and that’s all that matters, that I like it. But positive input helps thanks.

[work9to5]

Ok guys, so she’s done except for a couple minor things and one MAJOR detail. Because of piss poor planning on my part, I’m up against it on front rotor fitment. During the planning and mock up i omitted one important step, I never mocked the front rotor  I was thinking I could use the oem cb550 rotor on the front rim with spacers to get the correct alignment with the brake caliper. Both are 6 hole slotted and I figured they would match in bolt pattern. THEY DONT. The cb rotor bolt pattern isn’t the same as the rims rotor mount bolt pattern. So I’m looking for a way to get around this. Suggestions?

I’m thinking the easiest way is to find a rotor that matches the Suzuki bolt pattern. But it’s got to be “flatter” than the oem Suzuki rotor. The oem gs550 rotor is larger in width (won’t work with the cb caliper) and sits too close to the fork when mounted. Can anyone point me towards a rotor that has the same bolt pattern as the Suzuki but has dimensions close to the Honda 550 rotor?

Completely frustrated by this. She’s ready to ride but I’m not chancing traffic without a safe front brake. Other than this I’m completely happy with her. I’ll get better pics up over the weekend. And include pics of the different rotors and wheels then as well. Thanks

[work9to5]

Pic

[work9to5]

Pics

[calj737]

Get a rotor that fits the bolt pattern, then make a caliper mounting bracket to move the caliper the necessary distance. Simple.

[Gurp]

Loving where this build is going so far!

[work9to5]

Thanks Gump! Hey Cal, yeah I thought about that. But here’s my problem, I’m having a hard time identifying through the internet what rotors have the same bolt pattern and hub center hole that would match a 81’ gs550. This morning I went out to my shop and pulled every rotor I had that is not on a bike, just to see the different characteristics of each to help me brainstorm this. The first pic is a cb550, second cb750, gsxr750.

1.) cb500 holes don’t match slightly. I can thread 2 of 6 mount bolts, putting the other 4 ascew but close to where they need to be.

2.) cb750 pattern doesn’t match at all but interestingly it sits perfectly so that the oem cb550 caliper I had intended on using lines up perfectly

3.) 97’ gsxr750 rotor lines up with caliper as well but the center hub and bolt pattern are way off, but of course looks stunning

It’s 110 in my garage right now. I’m going to wait till the weekend when I can just sweat it out in there without having to go to work afterwards. I’m going to put the oem gs rotor back on and decide if it’s too close to the cb forks. But I’m thinking that it will fit but I’d have to bend an angle into any caliper mount I make. Which is not really in my garage capablities (I don’t have a torch or bend press).

What thickness steel/aluminum do you recommend using for a custom caliper mount? 1/4”? Anyone with ideas on this whole problem please lmk. Thanks

[work9to5]

Cb550

[work9to5]

Cb750

[work9to5]

Gsxr750

I’m post over the weekend as well details on how I’m building and upholstering the seat.

[Bankerdanny]

This might be crazy,  but how about finding a rotor for an '81 GS550?

[work9to5]

Banker, I covered that in the last post. The gs rotor sits to close to the CB forks. I wouldn’t have the room I needed to fit a caliper mount safely and the gs rotor larger in diameter.

I’ve been thinking about this all day and I think I’ve got a solution. I’m going to take the cb550 rotor and the wheel to my machinist on Monday. There’s enough room in between the stock holes to place evenly spaced holes to match the wheel. I tried doing it myself an hour ago. Got as far as putting 3 center punch marks in the rotor and realized I’m never going to get the accuracy I need. I don’t know what it’s called but I’ve seen machine shops with a chuck and a degree wheel on the receiving end of a drill press/mill. Anyone know what I’m talking about? What’s the proper name for that? That you can clamp an object in and spin thus getting a perfect circle, and you use the degree wheel to know that you’re where you have to be to dig your holes.

Hopefully they can do it the same day and I can be done with this. 🙄

[calj737]

If you are taking the 550 rotor to the machinist, drill out the stock rivets and bolt in a new ring. Then, drill new holes in the new ring exactly where they are supposed to be. Drilling more holes in the ring weakens the stock ring.