Hack mounting points for CB550F -Need ideas to keep OEM exhaust intact

[Megadeus]

I have a 1977 CB550F Supersport with the OEM swooped exhaust hanging down the right hand side. The exhaust collector is immediately adjacent to the right side bottom frame rail.

Has anyone here dealt with this exhaust system on a CB550F? Mine really looks too good to remove or hack up.


Not my bike but damn close.

[jaydmc]

For the lower front.

There should be two bolts that allow you to split the frame for engine removal. Take two thin plates and bolt it to both sides of the frame using two longer bolts. Then make attach them to a tube that comes down following the frame just a head of the frame. We could make you one of these using a CB750 we have in the shop as they are very similar.

For the lower rear, remove the center stand and make a braket that replaces the center stand (we can provide this one as it is the same as used on our CB750


For the two upper mounts use frame clamps which we can also supply.

Jay G
DMC sidecars
www.dmcsidecars.com
866-638-1793

[Megadeus]

I understand the 750 frame has a removable section but the 550 is a one piece. A subtle difference around the headstock. I can see how that lower front mount you suggested will work best.

[jaydmc]

I should have gone and taken a look at a bike rather then going by memory. The CB 750 is pretty much the same as the CB 550. The frame does not have a drop out section.
Jay G
DMC sidecars
www.dmcsidecars.com
866-638-1793

[MotoJ]

Just my $.02, but if your CB550F is as nice as the one pictured and is all original, I'd say don't hack it at all. Sometimes tugs aren't quite the same solo after towing a hack around, especially a bike with a light frame like that.

[Megadeus]

It's going to have a velorex 520 attached to it for dog hauling duty. I won't carry big weight till the mounts are sorted out. The CB is all original but not perfect by any stretch of the imagination. It's a 9 out of 10 for condition. Basically a time machine.

[Leaf]

Originally Posted by Megadeus

It's going to have a velorex 520 attached to it for dog hauling duty. I won't carry big weight till the mounts are sorted out. The CB is all original but not perfect by any stretch of the imagination. It's a 9 out of 10 for condition. Basically a time machine.

I have a 562 on my CB400 Twin. Even though it's a light hack, the forks don't rebound properly anymore after being continually subjected to the cornering forces caused by the hack. It also seems to be eating through speedometer cables really fast for some reason, but I am not sure if that's related to the hack-imposed forces or not.

I'm not saying don't do it, but I agree with MotoJ that it may cause significant additional wear and tear, which might be a shame on a still-decent machine that is probably pretty hard to find decent pit-free fork tubes for these days. :3

I made a bracket on the footpeg mount for my lower rear mount, that brings the eye bolt out past the exhaust. As a result, the lower rear mount is not square, rather it points forward and up, but it seems to be working ok so far. The mount gets in the way of the footpeg a little, which was annoying at first, but I no longer notice it.

[MotoJ]

Originally Posted by Megadeus

It's going to have a velorex 520 attached to it for dog hauling duty. I won't carry big weight till the mounts are sorted out. The CB is all original but not perfect by any stretch of the imagination. It's a 9 out of 10 for condition. Basically a time machine.

A 9 out of 10 time machine sounds perfect to me. Hacks are a lot of fun, but you should be aware of the consequences.
Just the empty car will be a lot of stress on that bike. A subframe might save the frame from twisting, but the swingarm, forks, steering head, shock mounts, etc. are all likely to get some tweaking. The wheel bearings will take a lot of abuse too.

At the least, I'd save that OEM exhaust and buy a cheapo MAC 4 into 1. Those originals are almost unobtainium nowadays. You could probably sell it to the right person and buy a whole other bike.

Whatever you do, post lots of pics!

[Megadeus]

Originally Posted by MotoJ

A 9 out of 10 time machine sounds perfect to me. Hacks are a lot of fun, but you should be aware of the consequences.
Just the empty car will be a lot of stress on that bike. A subframe might save the frame from twisting, but the swingarm, forks, steering head, shock mounts, etc. are all likely to get some tweaking. The wheel bearings will take a lot of abuse too.

At the least, I'd save that OEM exhaust and buy a cheapo MAC 4 into 1. Those originals are almost unobtainium nowadays. You could probably sell it to the right person and buy a whole other bike.

Whatever you do, post lots of pics!

I do have a 2nd CB550F in pieces and have a spare OEM exhaust in the rafters. A bit scuffed up but decent for 30+ years old.

[Pugsley/Hobbfather]

Does the 550 have the big triangles that hold the front of the motor?

If so, make new versions that use the same holes to mount frame to engine, and build mounts from those, they're a little high for lower mounts, and too low for high mounts, but they offer a strong place to start, I would think.

I've been making up a mounting system/frame for my '86 Concours that relies on a whole lot of cutting and bending to fab up mounts without a subframe, but I'm also not fighting with stock bodywork, as that was an impromptu roadside mod...

[Pugsley/Hobbfather]

What I mean by using both those plates, is to have essentially a bar that is cantilevered off both, so it's a solid piece coming out just behind the exhaust, in front of the cylinders...ish...

[Megadeus]

My bike does have the triangles attaching the motor to the frame at the front. I have the limited ability to fabricate items here at work. Attaching to the centerstand mount is a good idea too since that is a super strong point on the frame for obvious reasons. I'll overhaul the forks and springs rates for the additional weight. I will research fork oil substitutes with higher Extreme Pressure properties to help out the fork slider bushings live a slightly happier life.

Anyone have a leading link front end just sitting around?

[MotoJ]

Originally Posted by Megadeus

My bike does have the triangles attaching the motor to the frame at the front. I have the limited ability to fabricate items here at work. Attaching to the centerstand mount is a good idea too since that is a super strong point on the frame for obvious reasons. I'll overhaul the forks and springs rates for the additional weight. I will research fork oil substitutes with higher Extreme Pressure properties to help out the fork slider bushings live a slightly happier life.

Anyone have a leading link front end just sitting around?

Progressive springs will help you, or just preload the existing with some pvc spacers. You're gonna want a fork brace, a billet top plate, or both- that front end will twist. Steering dampener too, and a better front brake (drilled disk, stainless line, soft EBC pads), or look for a dual set-up.

Finding a used LL for your bike will be tough, I bet.

http://www.dimecitycycles.com/vintag...a-12-2112.html

[Megadeus]

After some discussion with some sidecar savvy folks.. I'm going to start designing a 100% removable subframe assembly. Going straight to the frame for the lower front mount is asking for trouble.
I'm going to start off with 1" square steel stock for material and go from there.
Here are the mounting points I'm thinking of using.

I'll duplicate the triangle stock with a triangle of my own and have a 1/4" steel spar running along side the frame tubing to the L shaped square tube frame I will have bolted to the lower engine mounts with steel ears.

I will run one square tube spar back to the center stand mount but I'm short on ideas on how to approach this one.

Run a bolt through the center stand pivot ( its hollow) to a u-shaped bracket that is part of the front assembly. Or keep it independent?

Here is how the exhaust affects the rest of the mounts.

[Megadeus]

I wonder how much trouble I can get into with this?