My stem won't come out. I grabbed my allen wrench and tried to but the bolt just keeps spinning. And idk if this means anything but the bolt can come out easily. It just doesnt seem to lock on to anything so it just spins and spins.. Also do you guys know anything about this bike? My uncle just gave it to me yesterday.. (Miyata, ninety)
Hi, my bike's name is Kyle.
Coulda, shoulda asked/researched BEFORE doing.
Hopefully, you will be able to re-thread the screw back into the wedge inside the stem so that the bolt is about 3mm (1/8 of an inch) above normal tightened position. Put a block of wood on top of the bolt, hit the wood with a hammer to push the bolt down until it is in normal tightened position. Now the the stem should come out easily; if not repeat above.
It's possible that the stem bolt has either broken or the stem wedge threads are stripped. Get a Phillips screwdriver or strong rod small enough in diameter to fit through the hole in the stem but longer than the stem bolt and see if you can tap the wedge at the bottom of the stem free. You might try spraying some Kroil or similar in the hole first.
Good Luck with that. I had a old 80's road bike where the stem had coroded so bad, due to dissimilar metals, nothing would remove it. What nfmisso said is good advice but you may have to throw the wood away and hit it as hard as you can with a ball-peen hammer once you screw the bolt back in. Leave the handle bars and front wheel on to give your self some weight and some thing to turn the stem with if you need to pry it loose.
"Where ever we go, there we are"
Soak it well overnight with a penetrating oil, such as Liquid Wrench which most hardware stores have. Use a rod to punch the wedge down as has been suggested than twisting sand pulling on the handle bars pull the stem out.
If really bad you will need to heat the head with a torch and than work on it. This will damage paint.
Never Give Up!!!