I am just finishing the total restoration of a 1976 Honda TL 125 SE, with the original Miller 150cc conversion in a Miller Highboy frame.  The clutch is virtually the same as the TLR and it's variants.  All the clutch components are the ones that came with the bike, apart from new clutch springs, clutch cable and clutch lever, which have been renewed.  I have checked that no components are missing, using exploded diagrams on the CMS website The clutch did work before the restoration, but the cable was badly frayed inside the sheath and the clutch arm was dragging against the exhaust pipe - both now rectified.

However, the clutch is stiff and gets stiffer as the engine gets hotter, increasing the drag to a point where you cannot change gear without first stopping the engine. 

What can I do to improve matters?

Thanks in anticipation

Edited June 19, 20206 yr by stpauls

Check that the clutch operating mechanism is actually giving you the full operating movement. From your description it reads that the clutch must be dragging from the start and is not fully clearing, this could all be down to the incorrect cable or adjustment process needs re setting. Double check everything is installed as it should, parts diagrams can be misleading.