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Hallo!
Is possibile to fit a 501 kokusan complete engine inside a k2 frame?
Someone experienced a work like this before?
How hard Will be?

Thanks

Technically nothing is impossible but it will not be straightforward.

I have seen a kokusan engine (including the starter) in an A3 frame before and that required lengthening of the rear engine mount bolt holes to be able to push the engine further back and some modifications to the front frame downtubes to give space for the front mounted starter, plus some custom front engine plates.

With the K2 you have the kinked frame and shorter front mounting plates so there is even less room for the starter motor. I very much doubt it would be made to fit without quite a lot of frame cutting.

If you were prepared to lose the starter motor then things get simpler as you could fit a primary drive cover from an earlier engine.

Of course exhaust pipes, ignition system (CDI, coils, starter solenoid, wiring loom) and regulator would have to come from the 501 donor and be modified to fit. They are quite different to the parts from a Ducati electronica series engine.

If you can make it all fit, it will be quite a fun bike though

Keep us updated!

Ok thanks cutting the frame Is too worky on the se old bikes... Probably downgrading the engine tò older ignition Will be cheaper and Better work

No need to downgrade ignition. Just change the clutch casing. The Kokusan equipment is superior to the Ducati setup.

I put a 501 in an earlier frame, the coils and ignition module mounts where the transducers mounted. The lack of a starter motor is a problem. However, I understand that the motor and starter fit in an early frame and just the front mount on the left needs a slight mod. It can be made to fit.

No starter motor Is a really big problem,
I prefer the K2 because It has the starter motor
I love my 501 camel but only kick starter Is a problem
Shutting off the engine in the traffico Is important while diving in the hot city of Napoli during the hot Summer

Tranforming the engine tò ducati Spark system Will Need tò change also the camshaft, the actual One has no machining for the ducati pickup system....unfortunately

At the moment I'm using a Kokusan 501 Coguaro engine with Ducati ignition/alternator.
Therefore I thought there were no differences to the camshaft pickup/tacho machining used in the later Kokusan equiped engines?

I have a 501 engine from Excalibur and there Is no way to screw the ducati rotor tò the camshaft

You can fit an alternative ignition system, not a Ducati one. SWF is on my bike

What you will need is the 350 stator and rotor on the generator side to fit the Morini starter motor.

Or find an early Excalibur 501 with the Ducati parts, then strip down to fit the Camel camshaft.

A lot of work.

Do you have some pictures?

Price?
Benefits?

I've had a 501 engine without (senza) the starter motor in my K1 frame for about 20 years. It uses the kokusan ignition system and the 501's exhaust system. It has the older left hand clutch cover from a 3 1/2 and a kick starter with the kickstart extender to clear the tarozzi rearsets.

I modified the New York exhaust system by shortening the rear downpipe by about 10mm about 50mm from the start of the downpipe. I did this to stop the exhaust downpipe from touching the frame behind the rear cylinder. I use the 501's carbs with a slightly modified 3 1/2 air intake box. The exhaust took me several days to work out how to fit it on the bike and I modified a New York/Excalibur centrestand so that it was shorter in height as this fits around the rear of the mess of the exhaust system.

I would also like to fit the kokusan starter motor to the bike but have lived with the kickstart for these 20 years. I agree the electric start would be a great improvement on the bike. I do have ideas about fitting one but it's one of my projects in my backlog as the bike generally starts and runs ok with just the kickstart option.

You could also consider the 400cc option for your current 350 (344cc) engine if you want a bit more power without major work to fit the complete 501 engine.

Loose the starter motor Is not and option...
Modify some manifold Is still something i can do and also search for some 500 manifold Is a good option

Probably i Will change the camshaft with and M type and rebuld the Excalibur engine with older ducati parts and take It Easy enjoing the bike

i've got a dart engine in a 1976 350 drum braked sport , it fits perfectly , i did not modify the frame.
the original ducati ignition even fits.
just one of the front brackets between the engine and the frame needs modifying to clear the starter motor.
nice to have a reliable electric start by the way

huub wrote: ↑22 May 2025 11:49 i've got a dart engine in a 1976 350 drum braked sport , it fits perfectly , i did not modify the frame.
the original ducati ignition even fits.
just one of the front brackets between the engine and the frame needs modifying to clear the starter motor.
nice to have a reliable electric start by the way

This sounds like the pre K frame which has more space in front of the engine. As you probably know, the German Morini's club magazine - La Strega - had a good article on how to fit the engine in the pre-K frame, and the UK club's magazine has several articles from Ian who ended up moving the rear engine mounts back to accommodate the engine with the Kokusan system and starter motor in a pre-K frame. The K frame makes the challenge significantly harder!

huub wrote: ↑22 May 2025 11:49 i've got a dart engine in a 1976 350 drum braked sport , it fits perfectly , i did not modify the frame.
the original ducati ignition even fits.
just one of the front brackets between the engine and the frame needs modifying to clear the starter motor.
nice to have a reliable electric start by the way

Do you have some pictures of the job?

julianharty wrote: ↑22 May 2025 16:29

huub wrote: ↑22 May 2025 11:49 i've got a dart engine in a 1976 350 drum braked sport , it fits perfectly , i did not modify the frame.
the original ducati ignition even fits.
just one of the front brackets between the engine and the frame needs modifying to clear the starter motor.
nice to have a reliable electric start by the way

This sounds like the pre K frame which has more space in front of the engine. As you probably know, the German Morini's club magazine - La Strega - had a good article on how to fit the engine in the pre-K frame, and the UK club's magazine has several articles from Ian who ended up moving the rear engine mounts back to accommodate the engine with the Kokusan system and starter motor in a pre-K frame. The K frame makes the challenge significantly harder!

Do you have a link tò check?