Originally Posted by
T-Mar
4 kg. is very heavy for a frame. It's not quite as bad if you're talking as rec'd condition, with the fork, headset and bottom bracket. The best indicator for frame quality is the required seat post/internal seat tube diameter, though given the apparent era, even the entry level sport models were using seamed, butted CrMo, so it may not prove anything.
Thanks T-Mar!!
So far was only told that the internal seat tube diameter is 26 mm.
However I don't see a big issue to source for stem as it should be common.