I like the idea of racing a single cylinder Ducati, but the bevel singles are a little too dated for me. No disc brakes and pretty clunky transmissions. I can’t afford a real Supermono. Who can? So I thought about trying to make my own single from a twin. Turns out people have been doing this for quite a while. There are 3 different ways I have seen to do this.

1. Remove one rod piston and cylinder and rebalance the motor like a typical single without a counter balancer. A bob weight is clamped to the crank to take up the space from the removed rod.. I rejected this since it would vibrate too much and wouldn’t be able to rev high.

2. Create a pivot arm and connecting rod as a counter balancer similar to the Supermono. This is pretty complicated to construct and turns out very complicated to get the weights correct.

3. Leave the extra rod/piston/cylinder in place as a counter balancer and remove the cylinder head and replace with a perforated aluminum plate to allow air in and out.

The 3rd option seems the best to me as the L twin has perfect primary balance and nearly perfect secondary balance. No counter balancers needed and not too complicated to construct.

There is a Facebook page called Ducati Supermono Replicas where a few people have been running engines like this for years with great success.

So here is my plan.

I want to build a “proof of concept” bike that uses a lot of stock Ducati parts so I can concentrate making the engine conversion and not spend a lot of time and money on trick wheels and a custom chassis.

For the engine I’m starting with an 1100 air cooled 2 valve monster motor. So it will end up a 550 single. (Actually 539cc)

I’m using an ST2 style frame since the original Supermono used a chassis layout similar to the St2.

I’ll post updates on my progress.

Ducati's new single. These will no doubt show up at racetracks. A claimed 83+ hp, more than the Supermono, they won't be slow.

Now that’s a motor!
I seem to remember a guy on the west coast did a 848 single project that got sone good press.
I look forward to this build!
Paul

Curious: Will the vent in the cylinder head "cap" have an upward-facing vent and some form of breather or filter on the end? Something to keep some slight oil through the rings from escaping?

I read again and now see you did not say which head you would keep. Which and why?

Thanks, MikeV

Hi Mike

I finished the “cap” and it is replacing the vertical cylinder head. I am just venting the cylinder directly to the atmosphere. Some of the supermono replicas I have seen actually put a small oil cooler right over the holes. Not sure if it actually provides enough airflow to aid in cooling.

Here is a couple of photos of the finished piece.

I also chucked up the cylinder and shaved most of the fins off.

Cool.....Thanx for posting I get the aired out head. Do you air out/port the piston crown too?? That vertical cylinder may ventilate the crotch of your leathers at 8k.

See ya,
Clay

Don’t really do anything to the piston. Just run the oil ring don’t need the compression rings.

Making the rearsets. Copied the general look from Woodcraft.