Fender / Mudguard mount + seat rails

I cut the mudguard to size then made a couple of mounts to weld to the frame. Once on I marked the bolt holes on the mudguard, drilled it and then mad a frame to go inside the mudguard to give it some support.

Once all that was mounted on the bike I bent up some flat bar to give the shape  of the stepped pillion seat. I welded some short pieces of bar that I’d tapped to 8mm to the top cross-bar on the frame and welded the seat rails to the mudguard so the they would also bolt up to the threaded holes to give extra support.

So that gives me the basic shape for the seat base, which I’m going to lay-up from fibreglass. I’ve made a few seats before, but they’ve been fairly simple, with a metal pan. This is going to be a much more complicated shape and process, but I want the seat to look really integrated with the tank and mudguard. My inspiration is the mighty Kawasaki EN450 (which also gave me the front wheel I’m using). I went as far as buying an EN450 seat in the hope it would magically fit my bike but of course it was miles off, and way bulkier than I actually wanted, but offering it up did give me some idea of what I want my seat to look like.

Kawasaki Z450LTD 81  1

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Tank mounts

To get the tank level I needed the rear mount to be above the top tube bu about 25mm and the front mount to be below by 15mm, so I used some box section tube of the same diameter to space the mounts out. The rear mount is just some box section cut into a U, with a hole drill into it and a nut welded inside. The front mount is a similar cut piece of box with two holes drilled and a piece of bar welded in to hold the rubber bungs. My positioning of the carbs is pretty good, there’s only a couple of mm difference in clearance between the left and right carb and the tank.

Side stand

Bike needs a side stand.  Well I could lean it against stuff, but that would be a pain. And for the MSVA test the stand needs to either be a spring loaded flip-up type, or have a switch to cut the power if you try to ride off with it down.  I don’t like flip up stands cos it’s just a matter of time till the bike ends up on it’s side. There’s loads of side stands with switches on ebay to choose from, in the end I had to buy two from different bikes and use the leg from one and the mount and switch from the other with a bit of modification to make them work together. I made a mount plate up and mounted the stand to the motor using some of the handy threaded holes Ducati engines have at the bottom/back of each side.

Rear Sprocket

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The sprocket that came on the rear wheel, from a z1000J, is for a 630 chain, and there’s no 630 front sprocket available for Ducatis. 520, 525 and 530 options are available, and I’ve got a sprocket from a KTM or Husaburg for 525 chain that’s about the right number of teeth, so I rough cut the original sprocket with my angle grinder, chucked it on the lathe, cleaned up the cut and marked it at the correct diameter to make the holes to mount the new sprocket. Mounting the new sprocket on the old one handily lined up the front and rear sprockets for a perfect chain line.

BMX bars

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I like quite a narrow handlebar. I found these BMX bars which I think will work, and I’m going to mount them in the normal way for BMXs and all pedal-y bikes. I thought pretty pretty long and hard about the wisdom of this, as it just doesn’t seem right. Motorbikes are heavier, right? But as I was considering this I watched Keith Code’s ‘A Twist Of The Wrist’, and that laid the answer out for me – Handlebars are for steering input, your grip on the bars should be loose, if you’re holding on tight there’s going to be all sorts of unwanted steering inputs. For this to work the seat and footrests have to hold the rider in place so they’re not forced to use the bars to hang onto the bike, so with that in mind I’m going to make the seat so it holds the rider in place, and maybe use knee pads on the tank to give the rider something to hold onto with their legs as they lean.