Project CB690 (KTM 690 engine in a CB550f frame)

[goodoltup]

Welder finished the swingarm and sent me these pics, they will drop it off soon!

 

[Jimbonaut]

Pretty sure I'd learn more in an hour hanging out in your garage that in 5 years fumbling around in mine

 

[goodoltup]

Pretty sure I'd learn more in an hour hanging out in your garage that in 5 years fumbling around in mine

Thank you Jimbo! But I doubt that's true, my process is just as much fumbling as everyone else, and I spent 3:1 time staring at the bike than actually working on it.

 

[goodoltup]

The brake disc needs to be spaced away from the hub 5mm, to prevent the caliper from fouling the spokes. I thought about machining some material off the back of the caliper, but it was too close for comfort. So when I designed the caliper bracket I counted on the disc being spaced out. The 5mm distance is just enough to prevent any interference, and because the disc is 5mm thick, I could use a brake disc as a spacer instead of machining up new 5mm washers. So, picture 2 shows the old disc cut apart (but not finished), and picture 4 shows it mocked up with new longer bolts and a new EBC brake disc.

 

[goodoltup]

Picture 1 shows the clearance between the shock mount bolt and the drive gear, a little too close for comfort. I may cut down the bolt head. Picture 2 shows the clearance between the brake disc bolts and the caliper bracket. This distance can never change, so I am ok with it.

 

[goodoltup]

Mockup with wheel, on the bench. The brake stay will be this 12mm aluminium rod. I'd like to waist it down in the middle a little, for looks.

 

[goodoltup]

First try on the bike. I had to cut off the fuel pump mount bracket that I made a few years ago in order to make the swingarm fit, but that's fine I will relocate the fuel pump. The centre stand spring now interferes with the bottom of the swingarm, but I have a plan for that. I will move the spring outboard so it doesn't need the bug C shaped part, or at least I will try that.

 

[goodoltup]

Mocked up with wheel so I can see how long a brake line I need. Coincidently, the brake line I have now is perfect, just need to order new banjo fittings. Happy with the progress so far. It looks 'good' now, like that's where the wheel is supposed to be. It always looked a little stretched before. I'm really hoping this livens the bike up a little, right now it just won't lift the front wheel off the ground, which I think is due to the excess wheelbase. This should make the bike look better and make it a little more snappy.

 

[goodoltup]

Fuel pump relocate! Back on page 7 (almost 2 years ago!) there were some comments about the size and location of the fuel pump. Well now I've relocated it to behind the LH side cover, and am much happier about how it looks. I made a bracket that not only holds the pump but also the rear brake reservoir. Still working on the bracket that is needed to hold the bottom of the pump. Then the coolant catch tank will also be relocated.

 

[goodoltup]

This is the bracket for the bottom of the fuel pump. I just used a 10mm rubber cable gland and some sheet metal. I welded a nut on the frame behind the pump where no one will see it, and the bracket gets bolted on. It was incredibly difficult to weld, so I just tacked it the best I could and will proper weld it when the bike is all disassembled and the frame bead blasted. Also will add either another nut and bolt or maybe a pin/location hole to prevent the bracket from rotating.

 

[goodoltup]

This is the bracket to hold the coolant overflow tank. I repurposed a bracket that was used with the original radiator, before I constructed the new one. There is a little tit on the bottom of the tank, that locates into a small tube. The rubber piece that goes on the tit is actually a brake bleeder rubber cover, repurposed. With the battery holder reinstalled it really tucks the coolant bottle away, you can hardly see it. Even if the shorter swingarm doesn't work out for some reason the relocation of the fuel pump and the coolant bottle will still be a good idea.

 

[goodoltup]

With the help of my neighbour and his lathe, finished up the brake stay. It is a 12.7mm diameter aluminium rod, waisted down to about 11 in the middle. Just for looks.

 

[goodoltup]

Did a lot of work this weekend but didn't take a lot of pictures. The reg/rec was located under the engine, and the wires awkwardly routed up behind the swingarm. It looked bad and exposed the reg/rec to road abuse. There was room under the battery box, so I relocated it there.

 

[goodoltup]

View of relocated fuel pump and other bits.

 

[goodoltup]

And here it is, the shortened swingarm! A test ride is next, after the bike is fuelled up and I change the ECU map back to the regular unrestricted mode. Major risk is that the chain rubs on the swingarm.

 

[pidjones]

Brake stay rod under compression when braking?

 

[goodoltup]

test

 

[goodoltup]

Brake stay rod under compression when braking?

Got me worried now, are they usually under tension? The bearing stack in the rear wheel compresses everything when the axle nut is tightened, so even if the rod were absent the caliper wouldn't move without a great deal of force. The rod shouldn't experience much load. Think it should be underneath?

 

[irk miller]

Got me worried now, are they usually under tension? The bearing stack in the rear wheel compresses everything when the axle nut is tightened, so even if the rod were absent the caliper wouldn't move without a great deal of force. The rod shouldn't experience much load. Think it should be underneath?

The caliper wants to spin with the wheel when brake is applied, so the stay is under compression when braking. Most stays are at least 1/2" tubing, so if your rod can manage similar loads all good from my perspective.

 

[Popeye SXM]

Got me worried now, are they usually under tension? The bearing stack in the rear wheel compresses everything when the axle nut is tightened, so even if the rod were absent the caliper wouldn't move without a great deal of force. The rod shouldn't experience much load. Think it should be underneath?

I come from a MX back ground. When the bikes started to use rear discs many of the calipers were mounted on top (to stay out of the mud) if the stay was strong enough all was well, if not it would bend which was usually harmless. Most are now locked in place on the swing arm near the axel