Fe570 vs Fe390 parts

B3RG · May 8, 2013

Hi I was wondering if parts from a 570 '10 will fit 390 of the same era. eg. oil filters, air filter, map swith wheels bash plate ect????
what are the main diffarences between the 2? is the frame the same but just a diff engine and bore??

mark2e0 · May 9, 2013

difference between the two is the con rod,barrel piston and header pipe i have the 570 and a spare 450 engine, when i change them around i only have to change the header pipe. :roll:
Hope that helps. :bounce3:

Possu · May 9, 2013

The 570 probably does have a different conrod but it's the complete crank that's different.

390: Bore 95mm, stroke 55.5mm

450: Bore 95mm, stroke 63.4mm

570: Bore 100mm, stroke 72mm

The 450 is a long stroke 390 whilst the 570 has it's own crank and piston assembly.

Conrod length cannot alter the engine's capacity.

mark2e0 · May 9, 2013

Is the stroke not governed by the length of the con rod ?.

Bergini · May 9, 2013

mark2e0 said:
Is the stroke not governed by the length of the con rod ?.

an engines stroke would be determined by the 'throw' of the crankshaft (the amount of throw would be measured from the center of the conrod pin to the center of the main shafts), wether its shorter or longer the stroke would be the same. longer or shorter rods would each have there own pros/cons but thats another story

Possu · May 10, 2013

mark2e0 said:
Is the stroke not governed by the length of the con rod ?.

If the distance from the centre of the crank to the centre of the conrod big end bearing is 30mm, then the stroke i.e. the distance the piston travels up the cylinder, would be 60mm.

I used to race Lambretta's many years ago and remember reading that in an ideal world, the conrod length should be double the stroke i.e. 60mm stroke = 120mm conrod length (centre to centre). Admittedly this was in the 1980's and this may have changed.

Short stroke = high rpm but lower piston speeds. Long stroke = lower rpm but higher piston speeds as for each revolution of the crank, the piston on a long stroke crank is covering a far greater distance. Higher piston speeds also exert more forces on big and little ends. Shorter stroke also means you need a larger piston to achieve the same capacity or swept volume, one benefit of this is that the larger bore allows the fitment of larger valves which is good for performance engines. There are benefits to a longer stroke, torque being one of them but longer strokes also means more stress on the crankcases. Ducati used to increase the capacity of the V-twins by increasing the stroke which led to damaged cases in race situations. Over the years they've reduced the stroke and increased the bore, culminating in the Panigale which has a very short stroke compared to its predecessors.

KMK · May 21, 2013

So I have been wondering about the possibility of fitting the 570s 100mm bore onto a 390.

Has anyone done this?

Noppy · May 21, 2013

Brilliant! A 390 big bore!

But wouldn't you need to change the injection timing as well? Otherwise it might start running lean?

KMK · May 21, 2013

Noppy said:
Brilliant! A 390 big bore!

But wouldn't you need to change the injection timing as well? Otherwise it might start running lean?

Yes, I suppose a custom map would be required to make it happy.

Possu · May 22, 2013

KMK said:
So I have been wondering about the possibility of fitting the 570s 100mm bore onto a 390.

Has anyone done this?

Because of the 390's short stroke, you'd end up with a very oversquare and revvy 436cc engine, can't see the benefit of it.

If you use the 100mm piston from the 570 and the 63.4 stroke crank from a 450 you'll end up with 498cc.

Fe570 vs Fe390 parts

Help Support Husaberg:

B3RG

mark2e0

Possu

mark2e0

Bergini

Possu

KMK

Noppy

KMK

Possu

Similar threads

Register CTA

Recent Discussions

Recent Discussions