Can't recall the weight of the Mk1 but it's in the garage. I will weigh it some time and post back here.
As for the ride, I know the changes Mike has made but not sure I'm a good enough rider to actually notice the difference. suffice to say the Mk 1 has been a firm favourite since i bought it six years ago and it was still my regular ride up to last weekend.
I swapped all the gear over from the Mk1 to the 725 and it rides really well. Compliant in the way that you expect steel to be but difficult on the basis of one ride to judge whether one frame is better than the other. will need to ride it more over the coming weeks to really get to know it.
However I definitely had that 'new bike' feeling and it was good!
For the record the changes between the Mk1 and the 725 are:
– Reynolds 725 heat treated tubing (stronger than 520 resulting in a lighter frame)
– Smaller diameter top tube (more compliant ride)
– 1 degree steeper seat tube (improves climbing)
– 73mm BB shell (for slightly better tyre clearance)
– back end is same as previous Prince Albert but lighter than the MK1
– Plates to bridge stays instead of tubes (slightly lighter)
– CEN compliant