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Author Topic: T6 valve timing  (Read 3731 times)

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Offline Jeffrey Rook

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T6 valve timing
« on: 11 Mar 2015 at 10:47 »
Hi My Douglas books are still lost so could someone please tell me the valve timing and the correct gap for the contact breaker points ? For some reason the back plug is very sooty while the front plug is correct ,the magneto has been rebuilt and the valve clearances are correct the bike has been dormant for several years and when I reassembled the engine I took a lot of trouble to get the valve timing as close to the book as I could but having tried everything else I am now having doubts about my earlier work ! thanks Jeff
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Offline eddie

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Re: T6 valve timing
« Reply #1 on: 11 Mar 2015 at 12:54 »
Jeff,
        I can't help with the figures for the timing - but if the timing was incorrect, it would affect both cylinders the same. Only the tappet clearance being incorrect would affect just one cylinder. Other than that, I would check for air leaks or an ignition fault.  Another forum member had a similar problem with a 'V' twin - that turned out to be a problem with poor quality repro HT pickup brushes that deteriorated very rapidly.

   Regards,
                  Eddie.
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Offline Doug

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Re: T6 valve timing
« Reply #2 on: 11 Mar 2015 at 13:19 »
Jeff,

From the handbook:

IO    5 deg.   BTC
IC  45 deg.   ABC
EO 60 deg.   BBC
EC 20 deg.   ATC

Tappet clearance is given as 0.006 inch, though not stated hot or cold (presumably cold).

-Doug
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Offline Alan Cun

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Re: T6 valve timing
« Reply #3 on: 12 Mar 2015 at 10:25 »
One thing I have learnt about BTH never trust that the reading on your points on one cylinder is the same as the opposite. For whatever reason the advance mech sometimes does not seat correctly. Could be caused by distortion of the housing where the advance spring is located or the end bearing plate is not right. I think the points gap by the book is 12 but some of the old mag re-builders said closer to 20.

The Maleny Swap is on Sat at noon and Sun 2 hrs up the mountain from Brisbane if you have time on the weekend we can point you in the direction of Doug owners. Our Location is usually the creek side of the event. Look for Alan and Des.

regards Alan
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Offline Jeffrey Rook

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Re: T6 valve timing
« Reply #4 on: 15 Mar 2015 at 11:27 »
Hi thanks for the help and info , the problem seems to be the mag as it died totally on Friday arvo so its going back to the mag man to be checked over , a bit annoying as I was hoping to ride in the V and V rally next weekend . I am glad Eddie told me the valve timing would be out on both as I was on the verge of pulling the timing chest apart ! When I get it sorted I will let you know what the answer to my woes was ! many thanks Jeff
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