Author Topic: Fuels  (Read 4707 times)

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Offline T35

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  • Join Date: Apr 2004
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« on: 07 Sep 2004 at 06:51 »
I'm using the higher octane premium grade unleaded petrol in my 1948 Douglas T35 - I add 1 cc of anti-valve recession additive per litre of fuel - has anyone had longterm experience using valve recession additives? - any failures? I found lead replacement petrol unsatisfactory - left very sooty deposits on plugs, pistons and heads and bike seemed to lack power.

Offline aggettd

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  • Join Date: Jul 2004
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  • Location: Nova Scotia, Canada
« Reply #1 on: 22 Sep 2004 at 16:39 »
Using high octane may or may not be helpful. Here in Canada, octane is boosted using MMT which is a manganese-based additive. Apparently, it is one of the best. Several of my friends with with vintage bikes (Velocette, Triumph, and Sunbeam) use no other additives in their fuel with no apparent valve recession. My Douglas has not been on the road long enough, or seen enough mileage to let me draw conclusions.

On the other hand, some other countries use different octane boosters which do nothing for valve recession. In that case, I'd use regular grade fuel with an aftermarket additive specifically designed to prevent recession. The cost of high test without valve seat protection is not justified, unless you need the extra octane to prevent pre-ignition.