What do i need to replace for my seized bike i think due to no bottom end oil??

[whitee10000]

What do i need to do to get my 70s 2 stroke 125 yamaha dirtbike running again? I ran it w/o oil in the bottom end. what needs to be replace? Right now it wont kik so i believe it is seize. please help me find out what is wrong and what i need to replace.. THanks

[Chanman420q]

well from my point of view, u only have 2 options, take it apart and find out whats destroyed or just part the beast out, i dont think ur gunna find a lot of parts for a 70's dirtbike.....

[Colby@C&DRacing]

It depends on how long you ranit without oil before it seized up. THe cylinder needs bored and an oversized piston installed. You also might have to split the cases and replace the crank since the bottom end bearing are lubed with the oil out of the gas they might be toast.:(

[member]

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[44oEX]

Your motor did not seiz because you didn't have any oil.
2 strokes don't need oil to run as long as there is oil in the gas your OK. the oil that is in the base only goes in the gears and the clutch not the motor it self. ( It's like a chaine saw you don't need oil.) I could have damaged the gear if it run to long on no oil.
The motor siezed because it's old. And it just happend to 2 strokes ones in a will.

[F-16Guy]

Depends on what seized. If it's the piston, you'll need to bore the cylinder and put a top end kit in it (piston, wrist pin, needle bearing, gaskets). If it's the bottom rod bearing (which it probably is), you'll need to tear the engine down, split the case and remove the crank, have a new rod and bearing installed, replace the crank bearings and seals, and put a top end in it if it needs it--or rings atleast. It may have seized due to lack of lubrication (not enough oil in premix, or oil injection system failed if it has one), not warming it up enough (if the piston's siezed, this is a common cause--cold seized), or it may have just been worn out.

[Juggalo]

i hate to say this man but its probably not worth fixing. if its a 70's 125 its worth probably next to nothing and parts would be hard to find for it anyways. you'd prob end up spending more to fix it than the entire bikes worth. send it to the scrap yard or sell whats left of it in parts on ebay.

[AndrewRRR]

Pull the top end off it and see if it's the piston that's siezed or the crank or tranny (if the crank will rotate with the cylinder off consider yourself lucky). If it was the piston, replace it, bore the cylinder, and be more careful next time. If it's the crank or tranny chances are it will cost you an arm and a leg to fix.

[hondafox440]

If you didn't put bottom end oil in, then you siezed the bottom end. That means you need most likely a new crank, rod, main bearings, big end rod bearing.

[wilkin250r]

How long has it been sitting? You could possibly have rusted the entire transmission if it has been sitting without oil. Rust probably wasn't the initial problem, but I bet it's your biggest problem now...

[44oEX]

If you didn't put bottom end oil in, then you siezed the bottom end. That means you need most likely a new crank, rod, main bearings, big end rod bearing.

The oil in the bottom end does not go in the crank. you could start a 2 stroke and run it for ever and it won't damage the crank because the crank on a 2 stroke is only oiled by the oil in the gas.

So if the bearing in the crank is bad it has nothing to do with the oil. No oil will only damage the transmission.