Engine full of fuel and seized up

[royhall]

Not necessarily, it may just be completely lacking in lubrication.

[philward]

So final check is undo con rod main bearing and try manually moving piston up and down - if moves freely, then must be a tweaked rod. Logically, if you disconnect one at a time, and turn crank you will be able to identify which rod (rods) thats tweaked?

[PJM47]

Not necessarily, it may just be completely lacking in lubrication.

Ok sound like a plan, will do this next.

[Trigger]

It should of still turned the clutch basket with the kick.

[PJM47]

Yes I think it probably would have turned if I tried hard enough but i didn’t want to go mad and break something else when it obviously wasn’t happy. it really really didn’t want to turn on the kick. It’s possible there’s more thank one problem of course but hopefully not. Also it is freeing up a bit from where this started when it wouldn,t turn on the crank either. Should find out soon enough thanks to all the encouragement to get on with it.

[PJM47]

OK so hope you are all still interested in this the one folks. Think we are getting to the end. Not sure who is on for winning the sweepstake.

So I removed one rod at a time as suggested thinking at some point it would free up, but got to the last one and guess what, it is still exactly the same, it turns a bit then gets stuck. As everything is loose it now actually lifts the crank out of the case / bearings if I try to turn it more. The primary chain is off at this point and there is nothing left connected just the crank sat in its slot, it won't rotate freely.

It looks like the big gear behind the alternator is right up against the case and maybe getting stuck in places, its very close anyway. So bent crank or maybe just that gear is bent? Should it be so close to the case?


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[royhall]

Just try oiling the shells they won't turn bone dry.

[PJM47]

Just try oiling the shells they won't turn bone dry.

Yes they are all fully oiled

[Trigger]

The wheel on the flywheel does sit close. It is very hard to bend a 750 crank, are the crank case shells equally worn ?

[MrDavo]

it now actually lifts the crank out of the case / bearings if I try to turn it more.

I'll take bent crank please Eamon. I've bent a Triumph T140 crank, and they are positively agricultural in comparison. Amazing what hydraulic lock can do, its the irresistible force meeting the immovable object, but something has to give.

[K2-K6]

It does sound like the crank is bent doesn't,  from the rotation description 

I'd not have guessed at that from the beginning.  On the positive side,  it shows how strong the rods and starter motor are 

[allankelly1]

Yes if the crank is binding in it’s main bearing journals then it’s most likely bent but since the force was transmitted thru the rods surly you should call them suspect too?

Good luck

Best wishes Al


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[royhall]

Not necessarily. The drag of bone dry shells could have moved them in the casings.

[Trigger]

Take the fly wheel off. Grease the shells , place the crank back in and bolt the cases together , then turn the crank by hand 

[PJM47]

Yes flywheel next. Doesn’t that need a special tool though? Any recommendations?

The wear on the shells is fairly even.

The flywheel gear is so close I can’t get my smallest feeler in between it and the case, that doesn’t sound right, and there are marks on the case where it looks to have rubbed.