b40rt Posted May 9, 2009 Report Share Posted May 9, 2009 Trying to get my bike working again. (Stolen / recovered) An air cooled Aprilia with Rotax engine. The flywheel has been spinning on the shaft after the woodruff key sherred. I think the crankshaft is ok, but the taper on the flywheel has suffered, question is does the keyway start from nothing, or has it been worn away by the crankshaft ? Anybody out there want to sell a flywheel, if required ? The wiring has all been pulled out but shouldnt be to difficult to reinstate. I've got the engine out, head off, but the barrel wont move. Of the 8 studs that secure the head 4 go through to the crankcase ? I've put release oil down and will leave it overnight. Is it best to remove these studs first ? Its still on the original piston so never been off . (32:1 smokes but works) The **** I got it back from said it had been seized, but I can see little evidence. There is one score, which is visible, but I can feel nothing with my finger nail. Worth doing anything about ? The plastic cover for adjusting the cluth has been off (cross threaded on the way back of course) The lobe of the slote has been snapped off and I suppose I will have to go in there to retrieve it. The clutch may also be buggered as it had been "adjusted" by the clowns. The splines for the kickstart are also looking a bit sad, can that shaft be replaced, and are they available ? There is no gearbox oil in it, but the sump plug hasnt been out (I know this as anything they have touched is buggered/rounded/missing) How did the oil gat out ? Could it be past the seal on the kickstart/gear shaft ? Although I have had this bike for approx 20 years, I have little experience with the engine because it has been utterly dependable. An advice / help gratfully received. Ross Quote Link to comment Share on other sites More sharing options...
jbswm Posted May 11, 2009 Report Share Posted May 11, 2009 the rotax motor is tuff,first thing i`d look at is taking off the head to look into the bore and shape of piston and rings.hope that is why the motor doesn`t turn over and not the main bearings!!...good luck ,but parts are not a problem to find for those motors...johnnyb Quote Link to comment Share on other sites More sharing options...
b40rt Posted May 12, 2009 Author Report Share Posted May 12, 2009 the rotax motor is tuff,first thing i`d look at is taking off the head to look into the bore and shape of piston and rings.hope that is why the motor doesn`t turn over and not the main bearings!!...good luck ,but parts are not a problem to find for those motors...johnnyb Hi jbswm The motor is turning over ok, I was told it had been seized, but I think what has happened it the flywheel has come virtually off and has hit the cover, stopping it turning. (I hope) Getting the barrel off is the problem a the studs are corroded. Thanks Ross Quote Link to comment Share on other sites More sharing options...
b40rt Posted July 30, 2010 Author Report Share Posted July 30, 2010 Update - Barrel should be back Monday. I discovered I had a 72.2mm piston (enduro- thanks for identifying MartinM) Engine should end up a 250cc, ports will also have to be chamfered. Also the head will require mods to the squish band (1.25 -1.50mm suggested by Peter Knight) Think the missing gear box oil has been getting into the crankcase as there is some clean oil on the crank, is this likely ? And does this necessitate a rebuild, I cant see a gasket so any suggestions gratefully received. Thanks in advance. Ross Quote Link to comment Share on other sites More sharing options...
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