Author Topic: Mark Five head overhaul  (Read 251 times)

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Offline My 4th bike

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  • Join Date: Nov 2018
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  • Location: North Coast NSW
Mark Five head overhaul
« on: 13 Feb 2019 at 21:22 »
Hello All
Got myself a Mark 5, ’’twas a little bent and not running.
My first Douglas, so I'm little ignorant on the incidentals.
I have a repair manual and parts list plus quite a few questions.
The heads had to come off, blown gasket, thought I’d give them the once over, it's not run for a fair few years. The valve guides are looking OK and the valves look near new, although the valve heads do seem to be well pocketed in the head. Some head studs have damaged threads.
1) Is there any information on valve spring free length, installed length and pressure?
2) Can the head studs and nuts be made from mild steel or do I need higher grade?
3) The tappet adjusters have flats and could do with a reface has anyone got the grind radius.
Attached a photo.
Thanks to all, great forum.
Cheers Eddie
« Last Edit: 13 Feb 2019 at 21:48 by My 4th bike »