Monster 1100 Engine In 900ss Frame

Not wanting to further pollute the similar thread about an 900ssie engine upgrade, I'll start a separate one.
Here is a picture to start with. More updates on progress as time allows.

 

Yes, it's a product we make for the 749/999 series. We used one to adapt to 900ss as we had to relocate the battery due to larger airbox. Here is a better picture:

 

@final_edition beat me to it. Here is a picture of the race version installed. The road version is identical save for the fuses relocated to make for road cooling hoses.

 

So, back on topic. Before getting into where the project is now, it might be interesting to look back to before I started this project. Warning: lengthy post ahead!

The goal of this project is to primarily increase the power of the Ducati 900SS produced in the 90’s. There are several ways of accomplishing this, e.g. installing a 944cc kit which was quite popular at some point. With the continued development of the air-cooled engines by Ducati, it makes sense to look at a complete engine swap for the latest version, the DS1100 twin spark, such as used in the Monster, Hypermotard, and Multistrada of the early 2010’s. The attraction of using this latest version is a power output of 100bhp, modern fuel injection, and 7500 mile service intervals.

Considerations before project start
I tried to weigh up the effort of installing a 944cc kit to all the things that might be involved in an engine swap. In the end, the effort of installing the 944cc kit, rebuilding an 25 year old engine, with only a relatively modest power hike, seemed not really worth it. So, I started looking at the issues that will come up in an engine swap. The list is fairly lengthy.

1. Engine should “bolt in” fairly easily, but the frame mounting lugs will need to be enlarged for the 12mm engine bolts the later engines use. Will the larger engine bolt heads and nuts fit into the lugs? Will there be any issues with the fuel injected intake system fouling frame cross bracing. Will the cylinder heads foul on the frame rails?

2. Using a Monster engine, the swinging arm bearing will be the same as the 900ss. Will it all just fit, or will there be a need to machine spacer, top hats, or some other modification?

3. With using the complete fuel injection system from the same DS1100 engine, a new airbox will be required. Will there be a need to fabricate something bespoke or will one from a donor bike fit?

4. The fuel injection system will require a new fuel pump that produces the higher fuel pressure needed for the fuel injectors. How much modifications will be needed to fit a fuel pump from the donor bike or other fuel injected Ducati?

5. A new oil cooler mount will be needed if it is to mount somewhere in the original location. The oil cooler is mounted much higher up in the Monster. Can the original oil cooler lines be retained? Will it be efficient enough to deal with the increased power output?

6. Will a custom offset output shaft sprocket be required to get the chain run correct? Can a standard Ducati one be used and machine some spacers?

7. A ECU and wiring loom will be needed, ideally from the donor bike to ensure compatibility. However, wanting to retain the original dash and switch gear, will it be possible to run the ECU “without a dash”, i.e. without a functional CANbus connection from ECU to original dash? How difficult will it be to connect the fuel injected loom to the original 900ss loom?

8. Wanting to retain the “silencer each side” setup, how much work will it be to adapt the original exhaust headers to the new engine? Will new header pipes be needed with a larger diameter in order to not restrict the engine output?

I’m sure there will be a few surprises along the way, but having considered the above issues, we still decided an engine swap was going to be worth it in the end. In for a penny, in for a pound…

The next post will be about what the reality really looks like and how the project has gone so far. It's actually not too far off from being able to fire it up, though it will need setting up on a dyno.

 

You can buy that!