250 xc flywheel

[evo550]

Does anyone know if an internal rotor flywheel can be exchanged for an external wheel without changing the stator?
1986 250 xc. Motoplat.

[JohnnyO]

That won't work, an external rotor ignition has a much smaller stator than an internal one.

[PEZBerq]

What do you need to change the rotor for?  Are you after a smoother engine response or is the exisiting rotor stuffed?  If you want a heavier flywheel for enduros you will need to change the whole rotor/stator combo.  BTW I thought an XC would have had the external rotor anyway.  Has it been swapped out previously for the CR motocross internal type?  Good luck 

[evo550]

Yep, I'm looking to smooth out power and give it some more torque/grunt down low.
The motor currently has nothing until upper midrange then comes on with a bang then revs to the moon.
The heavier flywheel I'm hoping will smooth out the power and provide a bit of false torque down low.
Fitted standard with an internal rotor.
Would they share the same crank with the WR and be a simple exchange?

[bigk]

The parts book for '81 says external rotor for XC, but my '81 XC430 has an internal rotor system. I don't find the power aggressive. I just bought a very low hour WR430, but haven't riddent it yet. I'll let you know the difference in engine performance when I do.
Cheers,
K

[JohnnyO]

Yeah the cranks will be the same, just need the external rotor and stator and will bolt right up. Has the motor been ported? Husky's are usually pretty smooth in the power delivery.

[PEZBerq]

The 86 parts book shows 250 XC with an external rotor motoplat - the same as the WR.  Someone has most likely changed yours for the CR internal rotor version.  Not sure you will get more grunt down low with a heavier flywheel though - just smoother transition through the rev range.  Make sure the timing is spot on and the jetting is right.  Huskys can blubber down low losing power if too rich at partial throtle openings.

Out of interest I have got an internal rotor ignition ready to fit to my 82 430 XC if (when!) my Motoplat mini 6 external rotor ignition finally dies.  I am hoping the 430 behaves itself when the changeover eventually happens

[evo550]

The motor came standard with internal rotor and is original 6 speed fitted to bike.
The timing could be out as I get alot of kickback when starting (almost every second prod).
PEZberg do you have timing specs for it? Would love to get a copy of the parts sheet, I'm in brissy as well, any chance......there's beer in it for you.
Does the internal rotor ignition have a lighting coil?

[PEZBerq]

Evo you can download the entire spares book from Halls Husqvarna website https://www.halls-cycles.com/Catalog/Halls-Cycles-Husqvarna.aspx  They have most of the old models there in pdf format including the 1986 model. 

The internal rotor Motoplats have no lighting coil as they were for the CR motocross models only. 

As far as timing specs I would time it the same as all the earlier Husky 250's at 2.55 mm BTDC.

Glad to share a beer - do you do any QVMX events?  Cheers

[evo550]

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