Fuel mix ratio?

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bob.keevil
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Fuel mix ratio?

Post by bob.keevil »

Hi all
On this Saturday I will be getting back my arrow from a engine rebuild with John Ellis, for the last 12,000 miles I have used my oil at a rate of one capful to two litres of petrol mostly (95 rather than97) as both bikes have run better on the lower rating fuel. After the big stop on the Lake side in June run I wonder if modern petrol may need more oil? How much is to much. I am thick so don't tell me what percent as that means nothing to me.
Cheers
Bob K
bh.sprint
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Re: Fuel mix ratio?

Post by bh.sprint »

Hello Bob,

Ariel recommended 32 to 1 for normal riding towards the end of the manufacture of the bikes-- which is 2.5 caps to 1 gallon of fuel ( 4.55 litres )
Using 2 caps per 2 litres ( a cap is 60 milli litres approx ) works out at near enough 32 to 1 ( 2000 m/l divided by 60 = 33 ; near enough to 32 to 1). ( a milli litre = 1000 th of a litre )

I use 32 for my bikes and it seems OK, I've done over 20,000 on all my bikes . On the first couple of 5 litre fuellings I use a ratio of 25 to 1 but after that go back to 32 to 1 when the engine has freed up a bit.
If the oil is increased, then the carb should be re-jetted but in the small oil increase used to go from 32 to 25 to 1 I've not found it to make much difference.

I use fully synthetic on two of my bikes and mineral on the other, the synthetic oil costs a bit more but it does smoke less and should give a bit more protection from seizures when the engine is working hard.

I use a plastic bottle marked up with 2.5 , 5 litres and 7.5 litres to save time when fuelling the bike.
Brian H.
bob.keevil
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Re: Fuel mix ratio?

Post by bob.keevil »

Hi Brian
Thanks for your reply , as I said in the past Ive run on 2 1/2 caps to five litres but was wondering about this wonderful stuff they now call petrol and if a increase would be any help as I have a big rebuild bill to sort out. Thanks again.
Bob K
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Re: Fuel mix ratio?

Post by nevhunter »

It's surprising how little oil is needed in a two stroke once it's up to running temperature. Most seizing is due to not having enough clearance or running lean or detonating. I wouldn't use less than about 32:1 and warm up carefully by not thrashing it till up to temperature. High silicon pistons run less clearance. Nev
bob.keevil
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Re: Fuel mix ratio?

Post by bob.keevil »

Hi Nev
Thanks for the info, Suzkui pistons are now fitted so a 500/700 mile running spell will follow. Thanks again
Bob K
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Re: Fuel mix ratio?

Post by Trev Sellars »

Castrol and others do an ap for your mobiles. Just put in the ratio: 32:1, alter the total of litres of fuel you put in, and it tells you how much oil to add. I have an I phone and it is saved and does come in handy, as I use the phone to buy the fuel anyway.
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