1940s matchless

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1940s matchless

Postby r wheat » Wed May 08, 2019 9:04 pm

Hi can any one tell me do 1940s g3ls need a additive in the fuel to prevent valve damage cheers Richard

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Re: 1940s matchless

Postby Rob Harknett » Wed May 08, 2019 9:29 pm

The answer has to be yes, unless the bike has been adapted to run on lead free fuel. Its been discussed many times here, have you tried a search on the topic. It may save worries your bike engine will quickly be totally wrecked, if you do not use an additive

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Re: 1940s matchless

Postby SPRIDDLER » Wed May 08, 2019 10:05 pm

Well Rob, I have to completely disagree with you there.
My reading and experience indicates that engines that have run for a few thou miles on leaded don't need additives unless, as some have said, it has had new valve seats fitted. I've never used any additive in my bikes whether they have new seats or old ones. There was a vast amount of discussion (aka hoo-haa) about this 'scare' (although very little in the past few years) and I would put the additive issue in the same class as the hype about the Millennium Bug.
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Re: 1940s matchless

Postby pkr87 » Thu May 09, 2019 6:21 am

As usual I agree with Spriddler, I have driven/ridden 1000s of miles on all sorts of vehicles without using additives and have had no valve seat problems except on Ford V6 engines that have done massive mileages. I do use a Castrol additive for my racing M.G. just in case. So! unless you intend to ride hard and far don't bother but considering that additives don't cost too much anyway use them to put your mind at rest

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Re: 1940s matchless

Postby Mick D » Thu May 09, 2019 6:31 am

Hi

I consider 'lead' additives to be snake oil in the same way as magnets in the fuel lines, lumps of metal in fuel tanks etc. - just another way of parting me from my cash with absolutely no benefit.

Use an additive if it gives you peace of mind but don't believe it's doing anything to protect your engine.

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Re: 1940s matchless

Postby Rob Harknett » Thu May 09, 2019 9:46 am

Guess you just read I said yes to you must use an additive upper cylinder lubricant. I am well aware of the comments made so many times here. I hardly ever add a bit of UCL to petrol in my bikes. Probably no more than the odd shot of Redex I used in the 50's. The facts are, our engines have survived pretty good over 50/60 years using leaded fuel. Has anyone done that amount of use, using unleaded fuel they also refer to as rubbish. I gums up your carb, rots your tank, strips your paintwork etc.
Unleaded fuel has not harmed my bikes, I am never going to do enough miles to find out if it will. Has anyone started off with a clean engine, and now done 50/ 100,000 miles, that can say unleaded fuel has not harmed there engine. One of my dirty old prewar bikes has only done about 10, 000 mile on unleaded fuel without any complaints, except perhaps a gummed up carb and rotted float. But that's only about a years mileage. I will probably never discover if unleaded fuel is causing any harm.

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Re: 1940s matchless

Postby SPRIDDLER » Thu May 09, 2019 11:40 am

Rob Harknett wrote: The facts are, our engines have survived pretty good over 50/60 years using leaded fuel. Has anyone done that amount of use, using unleaded fuel they also refer to as rubbish. It gums up your carb, rots your tank, strips your paintwork etc.

I think the gumming up etc. issue is due to the ethanol added rather than from today's fuel being unleaded.

Unleaded fuel has not harmed my bikes, I am never going to do enough miles to find out if it will.

I agree with you there, Rob, as many bikes nowadays are hobby rides rather than everyday transport racking up high mileages. As daily and holiday transport I put 26,000 miles on my '54 350 in 5 years which I thought was above average but there are some who ride harder, covering very many more miles per year without suffering valve seat recession.
I still have 2/3rds of a bottle of additive in the shed which I bought years ago when the scare was first raised but soon gave up or forgot to use it. As said, it'll do no harm, it isn't dear and using it will give peace of mind if concerned.
Mind you, returning from the Cornwall Jampot in torrential rain I inadvertently put about 2 litres of diesel in my near empty tank. I was wet, cold and stiff so through laziness I just brimmed the tank with petrol and set off. The ol' girl had never run so well.
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Re: 1940s matchless

Postby 39speedtwin » Thu May 09, 2019 3:15 pm

When unleaded fuel was first sold, we were advised to fit hardened valve seats if continuous motorway speeds were to be maintained for long periods.
This is not the case for our motorcycles, I personally use Shell super unleaded with an additive, in my bikes and 1950’s MG.

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Re: 1940s matchless

Postby raffles » Thu May 09, 2019 5:44 pm

I have always understood that the only engines at risk were the ones with iron heads
Tony

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Re: 1940s matchless

Postby Duncan » Thu May 09, 2019 6:16 pm

raffles wrote:I have always understood that the only engines at risk were the ones with iron heads
Tony


That was my understanding too Tony which would include most of the 1940's road bikes. I use an addative in my iron head bikes but then I was given three bottles a few years ago, I have friends who don't and have had no problems.

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