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Author Topic: Fuel for NF  (Read 239 times)

Dunders

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Fuel for NF
« on: April 29, 2019, 05:37:23 pm »
Hi all,

I didn't want to hijack Kris's thread, but I saw this from Randall:

Quote
5-Use gasoline 98 of high premium gasoline ( do not use biofuel)

and it jogged a memory from the recent VMCC test day at Jurby, so I thought I'd start a new thread.

The local Guzzi single guru came to discuss my NF (he has 6 pre- and early post-war Guzzis, so mine was a 'new' machine!).  I told him about the hesitation I was getting at full throttle, and he advised using premium unleaded with some octane-increasing additive for the singles.  His rationale was that back in the day Agip supplied the forces/carabinieri with some of the best fuel available in Europe, so that's what they should run on.  It seemed counter-intuitive to me, as the NF is such a low compression engine, and i've heard the 'jokes' about running on paraffin....   

I respect Alec's opinions on matters Guzzi, so I stored the conversation away for when I got back from the Stafford Show (which I've just done...) and my ageing synapses forgot it till I read the above quote.

Is there any collective wisdom on this?  Anyone wish to opine?

Thanks!

Paul
Paul

Lost in the Irish Sea....

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banquo

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Re: Fuel for NF
« Reply #1 on: April 29, 2019, 07:07:17 pm »
Almost as good as an oil thread this!  ;D
All I can say is that I've run mine on Supermarket unleaded since 2002, with no obvious ill-effects, other than carb furring up over winter, and it did that pre-ethanol too. Ethanol definitely goes for the tap rubbers, but my view is that it would run on kerosene or TVO once warm, although overheating might be a problem. Using ethanol-free fuel would resolve the rubber issue, and possibly improve the carburettor furring issue, but as ethanol increases octane rating I see no advantage in using premium fuel for that reason alone.

Just my opinion of course, but this from the AA pretty much covers it:

Pros and cons of Ethanol
Ethanol is compatible with modern exhaust emissions control systems and contains oxygen so enhances combustion and reduces CO and HC emissions. It has a high octane number so helps combustion.

But

Ethanol’s energy density is about 2/3 of conventional petrol so fuel consumption will be a little higher and volatility is increased which can contribute to higher evaporative emissions.
Critically Ethanol has higher solvency causing compatibility problems with rubbers and can cause corrosion in aluminium, zinc and galvanised materials, brass, copper and lead/tin coated steels.
Ethanol picks up water and contributes to corrosion and phase separation where Ethanol and any water held in solution can separate out into distinct layers. 
Ethanol can also cause starting problems at low temperatures.

Dunders

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Re: Fuel for NF
« Reply #2 on: April 29, 2019, 09:25:29 pm »
Almost as good as an oil thread this!  ;D

I aim to please! ;D
Paul

Lost in the Irish Sea....
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cloggy

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Re: Fuel for NF
« Reply #3 on: May 16, 2019, 03:39:44 pm »
If you are just getting hesitation at full throttle either the main jet is wrong or the timing is out/new condensor; The theory about the engine needing high octane is B******s. Do a plug chop