Cost of Machining Oil slinger for inner rotor kit.
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Sorry to dig up an old thread but what If I were to install a IRK and lightened oil slinger on a 125 ducar? What else would I have to do to it and could it be kick started if I left the original piston in it, and not a high comp one?
Cactus Jack
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IF your Ducar has the clutch lever up the front (non start in gear) ... then you can't fit a lightened slinger since they have the clutch on the crank with a built in slinger ...
You can fit the IRK but as Roost has stated ... you risk breaking your crank ... In the case of engines with the clutch on the crank ... the cast clutch basket can't handle the quicker rev up and increased revs ... You can buy a billet clutch basket though ...
He's spot on when he talks about timing advance in relationship to a higher compression ratio ... When the compression is increased , the cylinder heat and flame travel speed are increased ... if the ignition is started too early ... the engine will suffer from detonation which tries to shove the crank into reverse with a heap of force ... that results in cracked cases etc ... The weight and inertia of the stock flywheel and sling helps to resist the crank trying to reverse itself ... but there have been cases where the left side of the crank has sheared off with the flywheel still on it ... In a nutshell ... an engine should be timed to totally eliminate kickback at cranking speeds ... and that would require an expensive digital ignition with fully programmable advance curve mapping ...
Your best bet is to fit a Lifan 150 ORK which has a more weight than an IRK and has a wider range of advance/retard adjustment ... Whenever you fit a high compression piston , you should re-time the static and total advance and run higher octane fuel ...
4 stroke engines are different to two stroke engines ... 4 strokes require low initial advance , then gradual further advance as the revs increase (up to a certain point) ...
You can fit the IRK but as Roost has stated ... you risk breaking your crank ... In the case of engines with the clutch on the crank ... the cast clutch basket can't handle the quicker rev up and increased revs ... You can buy a billet clutch basket though ...
He's spot on when he talks about timing advance in relationship to a higher compression ratio ... When the compression is increased , the cylinder heat and flame travel speed are increased ... if the ignition is started too early ... the engine will suffer from detonation which tries to shove the crank into reverse with a heap of force ... that results in cracked cases etc ... The weight and inertia of the stock flywheel and sling helps to resist the crank trying to reverse itself ... but there have been cases where the left side of the crank has sheared off with the flywheel still on it ... In a nutshell ... an engine should be timed to totally eliminate kickback at cranking speeds ... and that would require an expensive digital ignition with fully programmable advance curve mapping ...
Your best bet is to fit a Lifan 150 ORK which has a more weight than an IRK and has a wider range of advance/retard adjustment ... Whenever you fit a high compression piston , you should re-time the static and total advance and run higher octane fuel ...
4 stroke engines are different to two stroke engines ... 4 strokes require low initial advance , then gradual further advance as the revs increase (up to a certain point) ...