A custom project - AKA "I think I have enough spare parts to build a whole bike"

[DesmoDog]

This is another long stalled project. I started playing around with it in 2005ish, spent a year or two on it, then stuffed it away. A few years ago I retired, and pulled this one back out to see if it's worth continuing. I decided it was. This thread will begin as a recap of what I've already done, but will eventually catch up to present time. The recap posts are actually taken from another forum so they may look familiar to some.

In looking at it there are a few things I'd do differently if I was starting on it now, but that's how this stuff works. The original idea was to buy as few parts as possible and use mostly what I had sitting around instead. Basically a side project with near zero cost. It's grown since then but I'll start from the begining.

Spoiler alert - This is going to cover the making of a hardtail Ducati. You've been warned.

And now that the purists are busy gathering their pitchforks and forming a mob I'll get on with it.

Back when the chopper craze was at it's height, when they had huge tires, huge engines, and huge prices, I used to joke about building a little bobber to be the antithesis of what all the cool kids were dropping big money on.

When I ended up with a spare engine I realized I had most of what I'd need to actually build one. So I posted a note on the bevelheads list to see if anyone had a neglected (aka CHEAP) frame they'd be willing to let go. The first reply I got was from a buddy who had a frame that fit the bill perfectly (aka FREE). Alrighty then, bluff called. Time to start building a Ducati bobber. (Thanks again, Rich!)

We met up at the Vintage Motorcycle Days at Mid-Ohio and I picked up the remains of a Ducati 160 frame that some complete hack had given him. The swingarm had been removed with a hacksaw, cutting into the pivot bosses in the process. The remains of the swingarm pivot was then removed from the frame with a sledge hammer. From what I can tell, the frame was laid down on the ground and beaten until the pivot was freed. And the subframe was bent. And the passenger peg mount was bent. And the pinch bolt bosses were crushed. And the serrated end of the footpeg mount was destroyed. They succeeded in removing the pivot but the frame was useless when they were done. Here are a couple bad photos of it as delivered.





No sane person would restore this frame back to stock. Maybe if it was a Vincent Black Lightning it'd be worth it, or some old boardtrack racer, but we're talking a square-styled Ducati 160 Monza Jr here. Out came the hacksaw and off came about 8 pounds of bent and battered tubing.



I've forgotten how I came up with the dimensions of the hardtail section. I probably I used a 250 narrowcase frame and swingarm I had, measured where I wanted everything to end up, and did the math. I bought the tubing from an online supplier, brought it in to work and manually bent it on a tubing bender. I didn't have a frame jig, so I drew a straight line on a tool stand I had and clamped the frame to it. Everything was centered and many measurements were taken when adding things. It's not a race bike, it'll be fine.

I ran the new chain stays out of the existing brackets with a 90 degree bend and ran them straight to the new axle plates. I used the hole that the rear brake arm pivot went through as a locator for the new frame tubes, enlarging them for the frame tubes to fit.






For the seat stays I decided to bolt them to the frame and then weld them too after everything was in place. Belt and suspenders, I know, but I don't see a downside. If I don't like how the bolt head looks, I'll grind it down to match the profile of the tube, braze over it, then smooth it all down so when it's painted no one will be able to tell it's there. The tabs are there to mount the pivot for a sprung seat. In hindsight this is one of the things I'd do differently, but I'm commited now.

Also, at this point of my life all I had was an oxy/acetylene welding set up so in the vintage style I tried bronze welding. It's not the prettiest but it's solid. I've wanted a TIG welder for ages but went with a MIG when I finally bought something. Still want a TIG... but hard to justify at this point in the game.





More later...

[DesmoDog]

I got the lower frame tubes (chain stays) done first to position the axle plates, then made the top tubes (seat stays) fit. When I bent the tubes, I left them long. I was about to cut the front section to size when I realized it would be easier to find 90 degrees with the long section still there. So, I cut the rear section to length and slotted the ends for the axle plates before I cut off the front section to fit the frame.

I don't have a mill so I put an end mill in the lathe, fit up a vise, and cut the slots in the chain stays. The set up isn't nearly as rigid as it should be, but for what I'm doing it worked as well as any other method I would use.





The chainstays are two 90 degree bends that butt together in the middle. There is no access to some of that joint to weld, so I ended up making a sleeve that would fit between the frame brakets and slide over the frame tubing. I slotted it so I could see the tubes inside and then welded everything together once it was positioned. There may well be a small plug inside the tubes too, I highly doubt they'd line up that well if there wasn't. It was a long time ago, I've forgotten.






For the axle plates I drew up some ideas and settled on the designs shown. The left side has to incorporate an anchor for the brake plate, a bar will be welded in the slot, which will locate the hub when it's installed and keep the brake plate from turning when the brakes are applied. I also left a tab on top for the fender mount.



I slotted the axle plate the same way I did the tubes, it just took longer! These days I'd use CAD to draw them up but back then I was still using pencils.

A lot of measuring and tacking and clamping. Midway to having the tubes set in place.

[DesmoDog]

Once the frame tubes were in place it was time to start bolting stuff on in a long line of mock ups. Most of them happened casually between doing other thigns so there isn't much documentation. I did end up buying a set of forks for it, but otherwise it's still pretty much left over parts from earlier projects. This is about as far as I got before I put the project on the back burner the first time.



More recently I had a valanced rear fender on the shelf so I tossed that on there along with some other stuff. The seat is not right yet. I had to rethink how that gets mounted but I wanted to get the foot pegs worked out first. Worked out as in straighten them. Every Monza Jr frame on the planet has bent footpeg mounts. True story.



I was kinda digging the valanced fenders but then not so much. I can assure you I"ll try them again at some point though just to be sure.

A lot of details change and change back just to change again on this.

[DesmoDog]

An even later look, the posts from here are from after I retired I think? Yes, the place is a mess. I should clean but I get distracted and do stuff like spend hours screwing around with rear wheels and frame braces/fender mounts not to mention tail lights and hey, maybe I could put forward controls on it! No wonder this stuff takes me decades to finish.



I had a few different fenders I was looking at. Seat and chain guard aren't in position, etc...

[DesmoDog]

Was it Pirsig who wrote about gumption traps? One of the things I spent WAY too much time thinking about how to fix was the bent/battered footpeg mount on the left side. Long story short, I decided doing anything was better than doing nothing, and that peg was getting fixed before anything else got done. After staring at it AGAIN for way too long trying to figure out how to make a simple frame to put a jack in there and force it back in positon (yes, seriously) I grabbed an old swingarm spindle and slid that in the frame, then slid an old fork tube over the peg mount. Push down on the fork tube, pull up on the spindle... and feel the footpeg tube give a little. Cool! Still not right though. Try again.

And... I broke the tube off. Well, not entirely, but it cracked. Not a big crisis, most of my potential fixes involved cutting it off anyway, this was just an attempt at a quick fix. So I tore it all the way off and saw some rust that indicated it had been cracked for years. The end of it was too beat up to use anyway. It would have been a hack fix, breaking it off was probably the best thing that could have happened. If I can break a peg mount off a hardtail frame by pushing on it with my leg, it wasn't a decent mount to begin with.

Peg mount is the hole in the middle. You can see on the right side of it where the tube was already cracked and rusty.



Time to fix this once and for all. I found some 3/4" round stock which was dang close to the ID of the foot peg tube. I cleaned up the break on the frame, cleaned up the inside of the tube, then turned down about 15mm of the round stock to fit into the frame - I used a slight hammer tap fit... after the oh crap I turned it down too far fit on my first attempt. Measure twice, cut once. oops.

I tried to find a replacement for the damaged serrated end of the tube, but struck out, In the end I cut the end off the tube on my 350 project. It wasn't my first choice, but desperate times and all that. The 350 has rearsets, it won't be needing these anyway.



With the frame using the holes that from the brake lever pivot, I moved the brake lever so it pivots on the centerstand shaft. That meant I needed to make a new shaft to accomodate both. I also sorta figured out the seat mount. It's not ideal but it works. (And now that it's been in place for a couple years, I think it'll be just fine.)

[DesmoDog]

I tried the valanced fenders in different positions, changed the seat mount, and welded more stuff in place. Once again decided not to go with the valenced rear so no big change in appearance and I'll skip the mock up pics.

On to planning the electrical system. I wanted to get a battery box and hide a modern battery and maybe a fuse block in there, but I can't find the size box I used on my 160 and don't like the stuff I can find. Hmmm... I pulled an old SAFA battery off the shelf that I had bought for my 160. It's an NOS part from who knows when, Cosmo was selling them back in the day. It's not something I'd ever use as is because 1) people who did try to use them reported they didn't last very long and 2) I despise old school flooded acid batteries.

But dang it's a nice size to fit the bike. I took some measurements and started poking around the interwebs, and wouldn't you know. One of the popular modern batteries people are using on these should fit inside the SAFA case. Well, it would if the case was hollow. Alright, let's see how these things are made. Just to clarify, this battery is old but has never been filled with anything. No acid or voltages involved. There is some lead involved, but I wear an old respirator when I do stuff like this because of all the dust anyway.

Here's the battery as it's sat for the last 50 years or so. That thing behind it is a top cover that will hide all the modern parts inside.



First step was to scrape the tar off the top and see how this is put together.



I thought the top was one molded piece, but when I started cutting it I discovered it's three seperate covers that are just sitting on the cells, the tar held it all in place.



Bash the covers off and the cells pull out in one piece. Much easier than I was imagining.



Once the case was empty, I had to deal with the internal walls that seperated the cells.



I ended up cutting slots in walls and breaking them out in pieces. They were brittle so breaking them was easy, but I tried to be careful not to break the outer walls. There is one spot where the break went into the wall but didn't go all the way through. For the most part I got to where there was some left on the outer wall and then shaved that off with a wood chisel.



So there it is, an old school dummy battery box. If my measurements are correct I'll have enough room on the end to place a terminal block if not a fuse block.

[DesmoDog]

I had been casually looking for a chromed rim to match one from a CB350 I had, but decided to just order a set of rims. I painted the original spokes, and decided to use a stock Ducati front hub instead of the Honda wheel I had.





Obviously the rear fender still needs to be trimmed. Flanged rims were not my first choice, but the non-flanged rims I found that were affordable had been out of stock for ages. So, I went with black flanged rims hoping they wouldn't look as massive as silver. The day after I got the notice that these had shipped, I got an email that said the silver non-flanged ones I wanted were back in stock. Typical.

Next up - the centerstand is too long. The stand is basically made of a bunch of plates welded together, but they all run at angles to each other so shortening this results in that being too wide and/or too low to fit back together again. I considered solutions that involved cutting and bending and patching and rewelding, etc. But this isn't going to be a show bike. So finally I took the thing off and cut the top off of it. Then I put the rear wheel on a block of wood and set the centerstand in place next to it with the two pieces overlapped so I could mark how much to cut off. Did I mention that somewhere I have a spreadhseet with all the geometry calculated to figure that out? Yeah... whatever, nerd.

I decided I had to cut an inch out of it to get it where I wanted. So I cut it again an inch further down.



Just as expected, nothing fit back together when I was done, but all that cutting and and bending and patching and welding wasn't going to fly. Instead I got a strip of steel, laid a few pieces of it where the gaps were, and started welding. (Obviously I've switched from oxy/acetelyne to MIG by this point)



It's no masterpiece but if you see that after it's been installed, something has gone horribly wrong.

After it cooled down I put it on the bike. Oops. I was shooting for the tire to be an inch and a half off the ground. It was more like half an inch. At most. Hmmm...

No worries. I also thought it was angled too far forward so I stuck an 1/8" shim where the swingarm hits the frame when it's down. Perfect. It's more like an inch off the ground now but that looks fine to me. I cut a strip of metal and welded it in place. Fixed.



Don't mind the red parts, that's the stuff I 3D printed to check the fit. They are printed with TPU (Thermoplatic Polyurethane) and the only black TPU I have is four times the cost of the red I have, so I use the red for trial parts...

[DesmoDog]

I had been chasing my tail on a battery tray and brake cable stop because I was thinking about ways to tie them together while still leaving room for a regulator. But I did't HAVE a regulator yet so I needed to figure that out. While I thought about that I printed a demo battery tray pad thingie - again, never mind the red. It will be black in it's final form, this is just a test fit part.



I also printed out a few battery trays to get an idea on how all of this is going to fit together. I used to use cardboard but this maybe reveals screw ups better than cardboard - I messed up the tray on my 160 when it went from cardboard to steel, this would have caught the issue. I got a lot of things wrong on early tries of this one too but I think I have it pretty much worked out now.



After spending WAY too much time trying to figure out a regulator/rectifier for this I decided to take the Powerdynamo ignition and alternator set up from my 350 project and use it here instead. Let's face it, the 350 is a long time away from being done and there are other ignitions out there that might work better for it anyway. Problem solved, now I have my regulator. Problem added; now I also have a black box for the ignition that has to go somehwere. More crap to hide. Not only that but the bike will now be 12 volts, and 12 volt batteries are bigger.

Solution: Screw the battery. A Powerdynamo can run the bike and lights without one and that frees up space in the battery case for the ignition black box along with some sort of fuse panel. I sense more 3D printing in my future.



But the real progress was the brake cable stop/stay/mount whatever it's called. I went with not trying to tie it in to anything else and just made a post for it and tacked it on. Pretty sure that'll work but I'll save the final welding until everything else is in place.



I'm not a big fan of that style brakelight switch but it should work, and it's simple. And I've got a back up plan for when I decide it sucks and I go with a different style switch. Looking at that picture I also see that I've reworked the brake pedal at this point. I guess I didn't document that but it got cut up and rewelded so it fit better.

I also managed to knock the bike over onto the concrete floor, but indications are it crashes pretty well. The tank did get a little ding but it had worse spots already so no big deal.

[DesmoDog]

I tried to order the "correct" TPU for the printed parts only to discover I was confused on what brand I was using, and the place I like didn't have it in black. That's probaby why I got red to begin with. So I ordered the brand I thought I was using which turns out to be not nearly as easy to print. I've been printing out some things anyway but will probably end up redoing them all before it's done. Again the red stuff is just for mock up.



The new TPU prints like crap if it's not set up just right. Here's what happens when you start a print after making some poor choices, and then you go do something else while the printer does it's thing.



That's a tail light adapter, to make it fit a smaller fender than what it was designed for. Now that it's printed (I have it in multiple materials) I'll likely end up going with something different because the adapter looks massive.

I hemmed and hawed about how to mount the rear fender and finally went with one idea just to have it done. Better to have something than nothing. Probably way over-built but at least the fender will be solid.

Check out the high tech fixturing!



Tacked in place. Seems to work.



I didn't have a matching set of levers and had been putting off dealing with it. In sticking with the "use what I have around" philosophy, I modded a lever to get a more or less matching set.

Close but no cookie


But after some cutting/filing, close enough. For now.


They need more work but that can wait until I get into final assembly mode. There are a LOT of things on this that are waiting for final assembly mode.

[DesmoDog]

One win was figuring out that the ignition black box will fit under the tank right next to the coil. Woo hoo! That frees up a lot of space in the battery box. This shot is basically proof of concept, it gets tight when the tank goes on but it will work. I'll probably tidy it up more but this inspired me to proceed with mounting the battery box.



I don't even want to say how much 3D printing I've done, mostly of things that end up getting binned. The good news is I finally ran out of magenta filament so no more pink parts. SO close to finishing the final part but had to change at the end. This shows a progression of battery tray designs, I've decided to make it a bolt-on part to make it easier to connect all the crap inside the battery box. The regulator attaches to the bottom.



I worked on a bunch of differnt battery strap designs to hold everything solidly on the tray, then decided to bolt the battery case to the tray and be done with it. The strap now only has to hold the lid on.




Here's the general idea. I'll add a fender mount off the end of it also.





Next up is the tail light saga. I'm almost up to the present time but that's enough posting for now...