flywheel jammed

[joeswoonara]

ok after a bit of a rebuild , running up the scoot i had a woodruff key shear ,replaced it started it up again , running rough flywheel nut had come loose , strange as it had been torqued !! suspected the rough running to possibly be the stator , fitted the flywheel puller , , flywheel seemed a bit tight then suddenly puller has stripped it threads off , ok i`m not beaten yet , borrowed a two leg and a three leg pullers , they wont budge flywheel , infact broke the fan , oh well i then broke the rest of the fan off to get the pullers on the steel part , still wont budge it i then grind all the bolts that hold the flywheel to the boss , again try the pullers this time with the boss heated red with blowlamp still cant budge the boss .........so flywheel trashed .....stator trashed .....and possible crank trashed .....i think it`s beaten me , before i take it out in the back drive and pour petrol over it
any one got any ideas how the flywheel boss 1. how it might have become stuck so solid and 2. how to possible get it off

[Yanker]

is it points? Had a Ducati flywheel where the pins that hold the magnets aligned and in parted company through centrafucgicl force gouging into yjr inner lip of the mag flange. Stripped the full gearbox (that is what it felt like) before detecting this. Also if you have fitted electronic but used the original LI fly nut and washer the flywheel could have slipped and be bound on the mashed taper and woodruff key?

Situation 1: look and cut pins

Situation 2: Carefully drill out fly boss rivets. Dunno if it is logistically possibe? Remove crank+Mag+Flywheel as one piece, as minus fan you can presumably release the mag housing? Nah thinking about it the crank would probably bind before the mag is free. Cut the conrod as close to the webs as poss and sacrifice the crank...sounds like it is probably toast already.....
+

[joeswoonara]

it was an Indian flywheel , its all smashed up now , the centre boss is still jammed on the crank , cant see what cutting the conrod would do i`m trying to save the crank

[dave411]

Sounds like the boss has welded itself to the crank.I've had that on old Outboards with big flywheels.Normally grind it off,but room may be a problem.

[Grumpy225]

it was an Indian flywheel , its all smashed up now , the centre boss is still jammed on the crank , cant see what cutting the conrod would do i`m trying to save the crank

From the sound of it the crank is already junk.


If you just have the boss on the taper you can carefully use a grinder to cut off the boss (like removing a flywheel bearing race with out a press). This way you can at least remove the crank with out having to cut anything else apart. Once it's free the damage can be correctly assessed.

Photos help.

[mick1]

Could you now not get a "normal" puller on the boss, if not angle grinder would be worth a go.

I suppose you could take the crank out and have go then, or take it to a local engineer.

[ulyssescale]

I had got my hands on an Indian electronic flywheel that did not fit into the stator. Meaning, the boss was larger diameter than the opening in the stator and it jammed into the opening when I torqued it down. Tried to start the engine up and everything got f@@ked.

[Tractorman]

Sorry to hear of your predicament. It may have been caused by the old key shearing and the key damaging the taper in the flywheel or on the crank and when you tightened up the with the new key in the tapers locked together. You say the threads on the puller were stripped so those in the flywheel are still good? If so get a new puller and make sure it's fully screwed in then put some pressure on, then with an electric welder run a weld along the boss of the flywheel that follows the keyway. Heat from the weld may just expand the boss enough to break the joint.

[DigDug]

Could you now not get a "normal" puller on the boss, if not angle grinder would be worth a go.

I suppose you could take the crank out and have go then, or take it to a local engineer.

He'll have a job getting the crank out with the flywheel still on it.

[mick1]

I agree but with only the boss left it may be possible to take out the mag flange and the crank at the same time.........or maybe not