T140V - WORN CRANKSHAFT

[sTe140Ve]

All my crankshaft journals have no wear at all but unfortunately due to a loose rotor key there is bad wear to the keyway and the bore of the rotor and corresponding crank face also have wear. My local engineering shop say they can reduce the diameter of the crank by a few thou but would then need to reduce the internal diameter of the rotor to match. He says he can make a new "core" for the rotor but does anyone know if the existing core can be pressed out in order to do this?  

[L.A.B.]

My local engineering shop say they can reduce the diameter of the crank by a few thou but would then need to reduce the internal diameter of the rotor to match. He says he can make a new "core" for the rotor but does anyone know if the existing core can be pressed out in order to do this?  

I've heard of people machining the crank down and fitting a sleeve to bring it back to the standard diameter.

Many later Lucas rotors had the magnets welded to the core (generally identified by the stamped rotor number) as the previous non-welded rotor bodies could become loose on the core.

One option could be to have the crank area plated and ground back to standard, or have the area metal sprayed and then machined back to standard could be another option?

Apparently, 'Sparx' rotors are puropsely made with their bores undersized, so that they are a fairly tight interference fit on the crank (to some people's annoyance when they've tried to fit them!) so perhaps your crank can be machined to take a Sparx rotor, as they are likely to be a tighter fit than an original Lucas rotor?

  http://www.tri-corengland.com/acatalog/SPARX_products.html

[Rex]

The "core" won't press out, and all that machine shop time will cost money. Another crank from Ebay might be cheaper, or you could have the crank machined as suggested and then fit the traditional rotor driver arrangement so-beloved of British bike problem pages way back when.

[Justin_Faithfull]

Finding a replacement crank is probably the easiest & cheapest option, but another possibility may be to have the crank built up & machined back to the original standard size. Welding, metal spraying or hard chroming?