I was lucky to score a set of 5 NOS, OEM clutch springs for my 89 KX125 restoration last week. I ordered some springs on Ebay that were advertised to fit my bike, but they were 2mm too long and felt more like KX500 springs. I was afraid of stripping the threads by forcing them on, so they went on the shelf.
Are there any companies that can make or at least look up springs by dimension? The 89 KX125 shared springs with only one other model, a KZ305. The springs changed in 1987 and again in 1990. Only two years on a very old bike.. nobody makes them anymore (including kaw).
Rough dimensions (as best I could with my micrometer):
Spring width (OD): 19.3mm
Spring width (ID): 14.5mm
Spring length: 40.0mm
The old springs were worn out.. 38mm measured (length).
The ebay springs were 42mm in length and too long to fit.