Author Topic: Mark 4 forks + valve guides  (Read 375 times)

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Offline Laurie

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  • Join Date: Aug 2022
  • Posts: 13
  • Location: Devizes, UK
Mark 4 forks + valve guides
« on: 30 Sep 2022 at 13:52 »
Recent purchase of first Douglas. Front forks inoperable. One has reasonable resistance. The other none until a sash cramp vigorously applied. The travel was the same so assumed different springs. The bottom cap on the soft side was difficult to get moving and that on the strong side worse. Some form of loctite used to compensate for v poor threads. All the strip down evidence on the soft side suggests never been apart. Tapered spring (I read somewhere = more comfortable ride than parallel spring if riding solo). Surprised when second fork's spring also tapered at same angle BUT one weighed 1.134kgs against 1.000kgs whist the parallel weighs 1.300kgs. So were there two tapers i.e. medium and soft?
I'm lucky enough to have a toolpost grinder on my lathe so can grind to create a matching pair of softs but won't do so yet in case it's the soft spring is a maverick.
I can't source valve guides. The old ones look to be austentic? cast iron which is a pig to work with and tolerancies are so crucial I'd prefer to purchase if possible either iron or phosphor bronze. They're  not available via the club at present.
Laurie Packer