Well you asked for another Ducati build

[buzzer]

Your welding looks good

Chris.

to be honest that's poor... there is no penetration, but that was on purpose as I wanted a clean look on the underside, which is what you see... the weld will be covered

Next job will be the exhaust system but to do this I needed a silencer to get the mock up right… I wanted a small slim silencer, that was re-packable, and that I could fit a baffle come MOT time… and a bit retro/old school. I searched but couldn’t find any suitable, they were all too wide as I want an under seat, side mounted setup. so I modified a cheap (£16!) stainless steel one off eBay. I would have loved to have made one from scratch but don’t have a cone roller, and to buy a ready made stainless cone is expensive. the hardest part of making this was actually drilling three holes for the bolts to hold the end cone in. the stainless is incredibly hard! after blunting 3 new drills, and buying a cobalt drill and that not touching it, I ended up making a punch and die and punching the holes!

[sirch345]

Your welding looks good

Chris.

to be honest that's poor... there is no penetration, but that was on purpose as I wanted a clean look on the underside, which is what you see... the weld will be covered

Next job will be the exhaust system but to do this I needed a silencer to get the mock up right… I wanted a small slim silencer, that was re-packable, and that I could fit a baffle come MOT time… and a bit retro/old school. I searched but couldn’t find any suitable, they were all too wide as I want an under seat, side mounted setup. so I modified a cheap (£16!) stainless steel one off eBay. I would have loved to have made one from scratch but don’t have a cone roller, and to buy a ready made stainless cone is expensive. the hardest part of making this was actually drilling three holes for the bolts to hold the end cone in. the stainless is incredibly hard! after blunting 3 new drills, and buying a cobalt drill and that not touching it, I ended up making a punch and die and punching the holes!

If you got what you were after with the seat tray welding, surely that has to be good

I like the look of the reverse cone megaphones

Chris.

[lloydie]

That’s going to make ears bleed I’m looking forward to seeing this one done . Keep it up

[buzzer]

That’s going to make ears bleed I’m looking forward to seeing this one done . Keep it up

loud pipes save lives

I have one on my other bike... its loud... but surprisingly not Harley loud...

[buzzer]

With the silencer finished I mounted it on the frame. I decided to make it rubber mounted to keep the vibrations down a bit. The collector was challenging… first one I made I was not happy with, so the second one I welded it on the inside with the TIG, which came out well and should flow OK. Stuck for a few days now as I need a couple of mandrel bends to finish it off.

[sirch345]

It's amazing how offering that up changes the look immediately.

I like the idea of the rubber mount

Chris.

[buzzer]

the speedo/ rev counter I am going to use has a plastic case... which does not look good. I tried to get some tube the right diameter but it was too big or too small, so I cut 12mm out of some bigger stuff and seam welded it back up, using a piston ring clamp to pull it together to weld it. I knew it wouldn't look right with a flat bottom so I made a conical one by spinning it in the lathe. The alloy needs to be soft for this so I annealed it by heating it up to temperature, and letting it cool. A neat trick to know when its the right temperature is to use a Sharpie pen, and when its burn off and has disappeared, its the right temperature! a bearing on the end of a bar makes it easy! here is a short video...

[sirch345]

Thanks for posting the pic's, video link, and the tip with the heat when it comes to annealing

Chris.

[AMCQ46]

you are skilled sir

[buzzer]

The seat base is finished, added the rivinuts to hold it on, and made a bracket so it only bolts on at the rear so it comes off easily. The last build is a pain to remove the seat. just need to add the foam and sand it to shape. I am happy with the mock-up but cant decide if the front mudguard needs to go central or biased to the front, but that can wait a while. the exhaust is all but finished apart from polishing and adding the hoops for the springs.

[buzzer]

many (many!) years ago I modified the frame on a Bultaco for a race seat. I put a complete back end on, much like what I have done here. I made very careful measurements using various fixings as datums, and welded it all up. soon as it was finished, and the seat on, it was evident that it didn’t sit straight on the bike. I was gutted as I had painted the frame. No one else noticed, but it bugged the hell out of me for years! I learned from this, these days, here is how I do it… I get the bike dead upright to a spirit level on the wheel, and then make sure the seat is level. seems to work!

I have also made a new purchase... an auto darkening welding mask... why the hell I didn't buy one years ago I just don't know! its so much easier!

[sirch345]

All looking good

Well done to your helper
I like the idea of levelling it all up

Chris.

[buzzer]

With the new seat the rear foot pegs were too far back, and uncomfortable for her legs, so important to get this right! I have made some new hangers out of 10 and 12mm steel tube. I made a jig first so all the angles and bolt holes were correct, and it wouldn't move as I brazed it. this is my first time TIG brazing and I was worried about strength, so I did a test piece first and tried to break the joint... the parent metal broke before the joint so all is well there!

[sirch345]

I like what you are doing there

Many years ago I had a 250 Rickman Montessa Scrambler (now referred to as a Motocrosser), that bike had a brazed together frame and that was strong enough. So your test was spot on

My Montessa had a different expansion chamber than this bike here, but this mentions about the brazing:
https://nationalmcmuseum.org/2020/10/08 ... tocrosser/

Where most British bike frames employed cast iron lugs and mild steel tubing, a Rickman chassis is large diameter Reynolds tubing, carefully fit and brazed together, then nickel plated. The end result was a bike weighing 30 to 40 pounds less than a factory machine. Over time, the Rickmans offered chassis kits for all sorts of engines and applications, even road racing, but this Montesa is among their first offerings of complete ready to race bikes.

Chris.

[buzzer]

been taking a few days off and getting about a bit on the bike and in the car. I have to say Covid and the restrictions to normal life have got to me a bit!

I got my parts back from the water jet cutter, another superb job! while I was there he was cutting through a 150mm block of exotic alloy, its fantastic how it just cuts through such thick metal. I designed the number plate bracket, the headlight brackets, and the number plate backing on CAD and sent it to him… a few days later I picked this up. I could have cut it by hand but this is so easy. I was going to sell the number plate, but I have decided to keep it… L90 fits the engine configuration! below is a short video of him cutting the plates

https://www.youtube.com/watch?v=lGbLKwYDoSg