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Ducati St4s Custom Build

Discussion in 'Builds & Projects' started by buzzer, Mar 3, 2019.

  1. You guys seemed to be interested in my multistrada special build, so I thought I would start a new post on my next custom build, which is going to be based an ST4s

    here is my original thread...

    https://www.ducatiforum.co.uk/threads/multistrada-special-build.65388/


    So here it is as it arrived. It’s a running bike with 22k on the clock. it’s not as tidy as it looks in the pictures, the paintwork in particular lets it down. It’s a runner, but it had some electrical issues, which were easy to trace, the loom was a mess!


    I have now stripped off all the parts that I definitely know I won’t use, and these are being sold to fund some of the build. First little job has been to machine the top yoke and rough some clamps out so I can fit conventional handlebars, to make it easier for me to move it around, and so I can sell the originals.


    I am not sure yet on the style this will end up, but it needs to be reasonably easy to ride, no clip ons! I am also going to make a tank in alloy this time, and work is already underway designing and making an English wheel which I am quite excited about.


    I took the Multi out yesterday for its first short ride and was REALLY pleased with the way it run on the new ignition and carbs... and that got me thinking... I don't think anyone has done a 996 engine on carbs...(most will say why the hell would you!!) I like the idea! So I have sourced a pair of nice flat slide 48 mm carburettors! Watch this space!


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  2. rock on !! great to get a thread like this :upyeah::upyeah::upyeah:
     
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  3. Looking forward to seeing it progress as your last build. That sub frame & swing arm looks like a design from the 60's
     
  4. You could confuse people by putting a 916 mono as the seat?
     
  5. "That sub frame & swing arm looks like a design from the 60's"

    Yea, a bit like me! back in the 60's!!

    I have decided to give the keihin 48mm CV flatslides a go... these are off a Honda VTR, and apparently they are some of the biggest carbs fitted to a bike... unless you know different of course! they have come up really well...

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  6. a little bit of progress, I have made the first manifold out of plate and tube, its come out quite well... I have managed to mount the carb at the same angle it was on the Honda VFR it came off.

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  7. @buzzer a question for you. When you replace the FI with carbs, you’re presumably also removing the ECU do you then put a CDI unit in to control ignition? Or, how are you doing it? TIA
     
  8. Yes Paul, on the last build I used an Ignitech unit which has proved to be very good. its user configurable and can be used with a TPS if needed... here it is...

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    I have mounted to other carb, it sits high so I had to cut a panel in the tank to clear it. I may end up making a tank for this build, but for now I will use the original to get it all running

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  9. Late August and the weather is terrible… so I have made a start… for a few weeks before we go on holiday anyway no going back now as I have had the angle grinder out on the rear of the frame. I really don't want to use the ST4 tank though so I have managed to find a badly dented Ducati alternative in a breakers, which seems to fit after a bit of under tank surgery!

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  10. I was going to try to make a tank, but I really like the 996 one i have picked up cheap... but its taking quite a bit of work to modify to fit over the carbs. I have had to cut the bottom out and fabricate a new base. some of the welding is done, and I thought it best to dye pen the joints as its easier to correct leak on the outside of a joint, rather than inside when its all welded up... good job i did as there were two leaks. Dye penetration works amazingly well as you can see.


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  11. 999 :thinkingface:
     
  12. :neutral:

    well spotted... 999 :)
     
  13. BRILLIANT!
    Wish I had the imagination and particularly the welding skills to do something like that, nuts and bolts I can figure out and good old fashioned mechanics are no problem to me but the more intricate fabrication I very often find quite hard.
    Spent hours with a TIG welder the other week trying to build some basic ability and all I've got are sheets of steel with big holes in them and tungstens with big blobs on the end, sooooooo frustrating.
     
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  14. Thanks! TIG welding does take some getting used to... the secret is to get comfortable, and support your weld arm. I always weld sitting down if I can, particularly on thin stuff like the tank. setting are also critical, but there is a lot of info around that will give you those. its about practice...

    Finished the fabrication on the bottom of the tank, all pressure tested and no leaks! I have had problems finding a fuel tap big enough... most are 8 mm but the Honda carbs require 10mm pipe, they were a thirsty beast! found one in the end... but I wont be running a reserve. Also made a couple of short bellmouths to fit under the pod filters. they were made out of tube, and spun in the lathe to bell the ends out. to do this you need to soften the alloy first by annealing it. I have struggled with this in the past as you need to get the temperature right, but if you go too far, it suddenly melts into s a blob! the answer is simple, a trick picked up from a mate... scribble on the alloy with a sharpie pen... heat until the pen marks disappear, and stop heating! then let it cool. it works a treat!

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  15. sometimes you make stuff but are not sure… this is an example. I wanted the front of the bike to be clean looking… so I made this speedometer using a cheap GPS module that will come on automatically when the ignition is on. the holes are for some warning LED’s… not sure if I will use it yet. I am aware that technically its no legal to have a GPS speedo… but…!! Whats peoples opinions on the look?

    Also been practising my alloy welding with my new TIG welder to make a battery box for under the tank.

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  16. :upyeah:from me. I like the look of it. A nice piece of work.
     
  17. The exhausts are now fabricated, as is the seat, but I may shorten that a bit.. and I am undecided on the moto GP or the mega style of silencer, I guess I have plenty of time to decide.

    The seat was made out of insulation foam, and cut and sanded to shape, which is VERY easy to do. its then covered with a few layers of glass mat and resin. I also had the headlight brackets water jet cut, they came out really well!

    No updates for a while as we are off on holiday for a few weeks!

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  18. I pondered how to make a coolant header tank… ended up making one from scratch! I love the TIG welder!

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