Siezed 2 stroke

[LEO DPRO 037]

I went out to port gawler with a mate today and managed to sieze the engine on my kx80.
Kick start will not push down whatsoever.
I had fresh fuel and mixed it correctly so im putting that out of the causes list for now. Has full coolant and as far as i can telk the gearbox oil is still in there.
Was riding it hard all day getting big air off of the table tops but as i came into the last berm before starting a new lap... she chugged her last breath.
Now those of you that know me know im not very mechanically minded, so where do i start?

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[my67xr]

By any chance was there a big straight just before the last berm ?
And as you were slowing down for the corner you dropped back a couple of gear's ?

 

[LEO DPRO 037]

Yes exactly right.
Dropping down hard with no clutch i might add!

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[my67xr]

Yeah that's the only thing a 2 stroke doesn't like, high vacuum from decell, pulling minimal fuel into the barrel while everything is still very hot.

I suggest you mix up some oil and kero and pour about 50ml's or so down the spark plug hole and let it sit overnight at least.
Then see if it'll kick over.
If it does, it's time to remove the head and barrel to check out the damage.

 

[LEO DPRO 037]

Anything i could use other than kero? Like turps coz ive got heaps of that here!! So even if it does free it up there will surely be internal damage and parts need replacing, If that doesnt free it up how do you get the piston out of the barrel?

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[my67xr]

Kero is one of the best thing's due to the oil in it, when it evaporate's it leaves a film of oil on everything
It also soak's in to tight space's so it's great for unseizing engine's.

You may need to use the wooden handle of a mallet if it doesn't free up easily, but too much force will damage the bearing's and it could cost you a new bottom end on top of your top end damage.
Top end rebuild will be the minimum damage.
Top end rebuild's usually cost around $200 for new a piston kit, gudgeon bearing, a gasket set and a bore job
Sound's like you will want to go up a size in the main jet as well just for a bit of insurance so hopefully the problem doesn't reoccur.
Have you had the carby apart yet to check what jetting is in it ?
Hopefully they have upped the stock jetting when they fitted the bigger barrel/piston

 

[Gelousi]

And if you did seize your top end goodbye to that cylinder, will have damaged the nikasil plating... Expensive fix

 

[my67xr]

All depend's on how bad it is
This barrel from gottahgetacheaperhobby/Stu's RM85 had to be taken out to the 3rd oversize and the machinist i use was able to do it and not cut through the Nikasil.