mk 4 timing cover

[yosemite]

Been working on assembling the mark 4 douglas, everything seems good so far, however the timing cover has a bolt hole  centrally, verticallyat he bottom ,can some one please tell me what screws in there or is itjust a blanking plug?
there is a similar hole on my earlier t35, but again nothing there,
Looked at parts book and the workshop manual and cant see any mention of anything to fit there

[eddie]

Are you referring to the breather port? The central hole in the bottom of the timing cover should have an alloy tube connecting it to the round boss on the inside of the cover. These tubes often get damaged/flattened or the owner decides to tap a thread in the hole for a screw-in pipe fitting so that the oil mist can be lead away from the crankcases.

  Regards,
                Eddie.

[yosemite]

thanks,
must be the one, Eddie wasn't sure what went there, was getting worried as the one on the T35 has quite a bit of oil around that area, was thinking something had fell off
regards
Paul

[eddie]

Hi Paul,
            The boss on the inside of the timing cover fits over the centre of the magneto idler gear, so that the gear acts as a spinner to throw any oil mist away from the port. Any vapour then passes down the alloy tube to escape to the atmosphere. If the tube is badly damaged or missing, excess oil will escape unhindered from the breather port.

  Regards,
                 Eddie.

[yosemite]

Thanks Eddie
  Will take the timing cover of the mk4 to investigate. just stupid of me not to look properly  when I put it back on just assumed there was a blanking screw  to go in the hole  There was no damage to the inside of the casing so should be Ok The T35 is running well although there is a slight oil leak from that hole so dont want to disturb anything that I dont have to. for now I will put that down to riding it fairly hard over the last few days. I'll clean the cover when I put the battery back on (some fool left the lights on this morning when I came home from dropping my son off  at work) and ride more gently to check to see if that was the cause, may think about putting a fitting in the breather to take any oil to  help lube the rear chain.