What do you mean by true? The crank should be a square taper type, is it correctly mounted on the spindle?

if you are looking to replace, would get an external bearing type crank, as these are stiffer than square taper, and can't be installed any way other than the correct way.

For the bike, would also look at getting a shorter stem, the one fitted is very long by modern standards, the jockey wheels (green aftermarket?) look a little pointy as well.