Ducati Telaio Rigido

Discussion in 'Some Assembly Required' started by DesmoDog, Aug 23, 2021.

  1. DesmoDog

    DesmoDog Desmo was my dog. RIP big guy.

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    This is another long stalled project. I started playing around with it in 2005 I think, spent a year or two on it, then stuffed it in a corner. I recently sold a bunch of projects and retired, so I pulled this one back out to see if it's worth continuing. For now it'll be a recap of what I already did, IAnd it may not get done this time either. 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. All the work done to date was done 15 years ago. The idea was to buy as little as possible and use what I had around instead. It was supposed to be a side project with zero cost. I may end up finding a fatal flaw and abandon it for good this time but for now, enough of the pre-ramble. On with the main ramble. I'll start from the beginning.

    Back when the chopper craze was at it's height with huge tires and huge engines 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.

    I think it was when I ended up with a spare engine that I realized I had most of what I'd need to 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 hard tail Ducati. (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.


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    No sane person would restore this frame 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.


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    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 some 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. I had to enlarge the holes for the frame tunes to fit. First I turned up a bushing on the lathe so the bit for a hole saw would be centered, then tried to mount everything on the drill press. The test holes went fine with a 1" hole saw but when I went to do the frame things started to go wrong. It gouged the surface a little but I caught it before it was too bad. I got the hole through but it wasn't as clean as I would like. For the right side I went with a 15/16" hole saw and then opened it up with a reamer to fit the 1" tubing. I thought about doing this to begin with but decided the test holes were good enough... turns out it's a lot easier to drill through a flat plate than it is to drill through a bracket on a frame... oh well. Live and learn.


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    For the seat stays I decided to bolt them to the frame and 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 I tried my hand at 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.


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    #1
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  2. DesmoDog

    DesmoDog Desmo was my dog. RIP big guy.

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    I'm stealing some of this from a thread I made on a different site back when I was working on it so if I'm writing in current tense, I'm lying. This all happened 15 years ago.
    *******************************

    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.


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    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.


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    For the axle plates I drew up some ideas that night and settled on the designs shown. They aren't the same because the left side has to incorporate an anchor for the brake plate. That's what the slot in the front is for - a bar will be welded in there, which will fit into a slot on 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! Actually that isn't entirely true. The slot for the axle had to be 0.60" (Yeah, I should be stating that in mm but my tooling is in inches, so...) and I didn't have an end mill that size, and didn't want to be cutting that much metal anyway with my hack machining set up, so I first drilled a 0.50" hole where the end of the slot needed to be, then cut a 0.50" slot out on a bandsaw. Once that was done, I cut the slot to size with an endmill in the lathe, dropping one surface and raising the other in two separate passes.


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

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    #2
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  3. DesmoDog

    DesmoDog Desmo was my dog. RIP big guy.

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    Once the frame tubes were in place it was time to start bolting stuff on in a long line of mock ups. I did have to buy a set of forks for it, but otherwise it's pretty much left over parts from earlier projects. That's about as far as I got before I put the project on the back burner. Now I'm thinking I'll build it up as far as I can with parts I have on hand to try and figure out just what it would take to get on the road.

    Here's an early mock up.

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    A couple days ago I found a valanced rear fender on a shelf so I tossed that on there along with some other stuff. The seat is not right yet. I'm going to need to rethink how that gets mounted but I want to get the foot pegs worked out first. Worked out as in straighten the mounts. Every Monza Jr frame on the planet has bent footpeg mounts. True story.
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    Earlier I was kinda digging the valanced fenders but now I'm back to thinking non-valenced. IF I did the valenced look I'd probably put bags and driving lights on it too, but I'm thinking more of a bobber vibe than a mini bagger... though if I was staying true to going against current trends, a mini bagger would fit the bill!

    Bars will likely change, I'd like them a little taller but don't have anything suitable to put on there right now. The tank will likely stay because it's the only narrowcase tank I have left.

    So that's the status of my long dormant Ducati bobber project. Anything from here on will be real time.
    #3
  4. DesmoDog

    DesmoDog Desmo was my dog. RIP big guy.

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    Here's it's latest look. Yes, the place is a mess. I should be cleaning 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 crap takes me decades to finish.

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    I had a few different fenders I was looking at. Seat and chain guard aren't in position, etc...
    #4
  5. Tanshanomi

    Tanshanomi Your Favorite Uncle Supporter

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    oh-okay.gif

    Subscribed! I love stuff like this!
    #5
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  6. Beezer

    Beezer Long timer Supporter

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    also digging the valanced fenders but the rear is too long. visulizing about 3/4 of that so the back end is higher op the tire. not quite as far as the skinny fender in your last pic....
    #6
  7. Roadracer_Al

    Roadracer_Al louder, louder, louder!

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    In!
    #7
  8. DesmoDog

    DesmoDog Desmo was my dog. RIP big guy.

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    Was it Pirsig who wrote about gumption traps? One of the things I've spent WAY too much time thinking about how to fix on this thing was the bent/battered footpeg mount on the left side. Long story short, yesterday 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 to 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. Whatever, not the end of the world. Most of my imaginary fixes involved cutting it off anyway, this was just an attempt at a quick fix. So I tore it all the way off the frame, and discovered it had been cracked for years. I also admitted to myself the end of it was too beat up to use anyway. It would have been a hack fix. Breaking it off was the best thing that could have happened. If I can break a foot 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. And also the broken off tube.
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    Today I went downstairs with the intention of fixing 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.

    Then I started measuring things to figure out where to cut the tube off of one of my other projects to weld onto the end of this. I chickened out though. I'd rather not cut that frame, even if I won't ever use those mounts after having spent years (literally) working on rearsets for it. (See Gumption trap, above). So instead of finishing like I said I would, I posted on a couple Ducati forums looking for the part I need. SOMEBODY cut those off when they made their cafe racer. If nothing surfaces in the next week or two I'll cut what I need off the frame for my 350.

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    So that's where it sits now. Not much of an update but this could take a while and I didn't want you guys to sit there clicking "refresh" all week awaiting new info.

    EDIT: I'm realizing most of you have no clue what I'm talking about when I say the end is too messed up to use. The mount and the peg both have a serrated mating surface so the peg can be indexed at the right angle and not slip. I have no idea what these little ends things are called or if they can be sourced anywhere.

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    The teeth on the end of the mount have been smashed flat so only about half of them would mesh with the peg, and the end isn't flat anymore either.


    Why in the hell the bashers didn't give up before destoying the frame is beyond me. Some people should not own tools...
    #8
  9. Roofchop

    Roofchop Hands up mother stickers, this is a f**k up!

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    You could use Nord washers.....Probably :D

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    #9
  10. DesmoDog

    DesmoDog Desmo was my dog. RIP big guy.

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    I still haven't found a foot peg end but have one or two more sources to check before I cut one off my other frame.

    I decided to pivot the rear brake pedal off of the centerstand shaft, which meant I needed to make a new shaft to accomodate both. I was going to just use a longer 16mm dia shaft, but when I went to take the brake pedal out to 16mm (from 14) I changed my mind and turned down the end of the shaft instead. There wasn't as much left of the pedal boss as I expected. I needed to shorten the boss to make up for the added thickness of the centerstand, so the part of the boss I started opening up got cut off anyway. The kicker is, I'm not 100% sure I'll be using the centerstand, so may have to mod the shaft and add a spacer to move the pedal out again!

    I also kinda sorta figured out the seat mount. It's not ideal but it should work. I have 4" seat springs now but may buy a set of 5" springs to cut the mounts on the frame down. I still have a couple things to work out there.

    As mentioned, I may not use the center stand. It's too tall for one thing - I can cut it down but we'll see. The side stand works fine but doesn't look so great IMHO. I also have to relocate the spring for the centerstand since the new frame section gets in the way of the stock spring location.

    This is how it looks now, sitting on the sidestand. I know, it doesn't look like much has changed, but I'm telling you it has.

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    Oh yeah, that picture reminds me. The rounded front and rear fenders I have for this are both NOS parts (not the valanced front that is shown, I have a non-valanced front for it too). I'm not too excited about cutting them up so have also reached out for damaged fenders to use instead. I have a set of fenders off a later, "square style" Monza that would fit the bill, but I prefer the rounded ones. Then again, the tail light I wanted to use fits the flatter fenders but not the rounded ones, so who knows where this will end up.
    #10
  11. Roofchop

    Roofchop Hands up mother stickers, this is a f**k up!

    Joined:
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    [​IMG]Plenty of repro steel guards out there...
    #11
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  12. DesmoDog

    DesmoDog Desmo was my dog. RIP big guy.

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    Yeah... I've thought about getting a tank and fenders with a ridge in them, but I'm trying to not buy more stuff for this. I don't plan on any more single cylinder projects after this and my 350, so I may as well use up parts I have sitting around.

    It doesn't look like it, but I made a lot of progress on the seat mount this week. The picture from my last post? I ditched the seat bracket I had made and went with something else. I made some Delrin bushings to put on the top of the springs so they could get bolted to the seat without squeaking and rattling, and then today I cut down the frame mounts by about 20mm. It looks pretty much the same but I don't even want to add up how much time it all took. I've stopped worrying about that though. I'm retired now, who cares how long it takes?

    Am I the only one who will sit and stare at some detail for an hour before I spend ten minutes just doing what I've been thinking about? Seriously, there have been times when I've spent more time contemplating something than what it would have taken to change it, and then rebuild it if it didn't work.

    And every time I convince myself I'm going to cut down the valanced rear fender, I then put the skimpy one on there and decide the valanced fenders aren't going to work! Yeah, I know, a couple more "hey, nothing's changed" photos. This time I mostly wanted to get a valanced vs non valanced rear fender photos next to each other so the next time I think about pulling the damn thing off the shelf and trying it again I can just look at the thread and decide it's still not going to work.

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    Oh yeah, I also welded the frame brace in. The test welds went great. The actual frame weld, not so much. Not a disaster but I think I'll break out the eraser and redo one side at least... Structually it's fine. Aesthetically... not so much.
    #12
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  13. DesmoDog

    DesmoDog Desmo was my dog. RIP big guy.

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    I've been working on this, but none of the progress would show up in pictures. The seat mount is worked out with everything tacked in place. The weld I wasn't happy with has been addressed. I bit the bullet and cut the footpeg mount off my other frame, so that's now worked out with everything tacked in place. And then I gave in and ordered some rims for it so they will match. They aren't the style I wanted but they were in the price range I could handle. More details when they show up. I hope I can find all the old spokes so I don't have to spring for new ones. DANG Buchanans is proud of their stainless spoke sets... I mean I've used them before and like them alot but were they always $100+ per wheel???


    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 I think? 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 case of the SAFA battery. Well, 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.
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    First step was to scrape the tar off the top and see how this is put together.
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    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.
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    Bash the covers off and the cells pull out in one piece. Much easier than I was imagining.
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    Once the case was empty, I had to deal with the internal walls that seperated the cells.
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    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.
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    So there it is, an old school dummy battery box at zero added cost. If all my measurements are correct I'll have enough room on the end to place a terminal block if not a fuse block. Next up I'm trying to source a regulator for it. I was looking for a new, small, cheap part off a CB125 or something, but may have found an original one that I wouldn't have to hide. Which is good because as I recall the originals aren't small.
    #13
  14. DesmoDog

    DesmoDog Desmo was my dog. RIP big guy.

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    I decided to order a set of rims for this instead of trying to match something I already had. I painted the original spokes, decided to go with the stock Ducati front hub, and started to build the front wheel. Surprise! 36 spokes. 35 nipples. Great. I stole one from the back wheel and kept going. Today I got a replacement for the missing one from someone on the bevelheld list (Thanks again, Frank!) and finished lacing up the back wheel too.

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    Obviously the rear fender still needs to be trimmed. I've changed headlight shells - it's the same size (130mm) but this one has a boss for an igniition switch, plus I have the internals for it. The sidestand will likely be removed so I can use it on another bike.

    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. Oops.

    I trimmed a front fender to see what it'd look like. I was a little restricted by the damage on the donor part but overall I don't think I like the shorty fender, so back to the valanced front once again. And that means the matching "round" rear fender. I like fenders but it sure would be an easy way to go...
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    It may not look like it, but this is the most progress I've made on this thing in ages. Now it will get shoved to the side once again though so I can start working on my trackbike project. I bought a very used '96ish 900ss that has been a track bike for years, and I need to freshen it up a bit before spring. I might work on this at the same time but don't quote me on that.
    #14
  15. Tanshanomi

    Tanshanomi Your Favorite Uncle Supporter

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    I like the painted black rims. They suit the bike’s alternative history vibe. After all, a lot of the original bobbers were surplus WWII military bikes. Johnny Strabler would think they look boss.
    #15
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  16. Wildebeest90210

    Wildebeest90210 Long timer Supporter

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    Agreed, I like a black rim, did them black on my Metisse.
    #16
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  17. sruss67

    sruss67 Been here awhile Supporter

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    Same here, the black rims look really good.
    #17
  18. DesmoDog

    DesmoDog Desmo was my dog. RIP big guy.

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    Well I'm glad you guys like the rims, cuz they're not getting changed now! :-)
    #18
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