Author Topic: Mark 5 Excessive Exhaust Smoke  (Read 2309 times)

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Offline pancho16

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Mark 5 Excessive Exhaust Smoke
« on: 06 Jun 2014 at 10:34 »
On Douglas Mark 5 1951, I am getting Clouds of Smoke on nearside exhaust.     Also thick Black oil is pumped into Silencer .     (other cylinder o.k.).  I have checked timing case breather is clear.     Piston is marked JP777 plus 020.         Replaced piston rings & replaced Gaskets purchased from D.Club  (the old oil scraper ring was a  double ring-the new is single).           Still same result on reassemble.       What should be my next step??

Offline Vermont-Ian

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Re: Mark 5 Excessive Exhaust Smoke
« Reply #1 on: 06 Jun 2014 at 21:17 »
Hey Pancho

Could be worn valve guide(s) on that side.

Ian
Ian Stokes
Richmond, Vermont, USA
1948 Mk III
1936 Citroen 'Traction' 7C

Offline C Clay

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Re: Mark 5 Excessive Exhaust Smoke
« Reply #2 on: 07 Jun 2014 at 16:30 »
Hi Pancho,
I had a similar experience, see link below, I found that the issue was the lack of clamping due to tight threads on the head studs.
Freed threads, Fitted new gasket, and retightened after running for about 10 minutes, no issues so far.

https://www.douglasmotorcycles.net/index.php?topic=5274.0

Regards
Clinton

Offline pancho16

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Re: Mark 5 Excessive Exhaust Smoke
« Reply #3 on: 12 Jun 2014 at 12:44 »
Clinton & Ian-thanks for your advice-will try to sort bike now .  Regards Pancho

 

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