Float level and E fuels

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Fred
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Float level and E fuels

Post by Fred »

The float levels in the manual were issued what 25 years ago. I have become aware now that fuels are not the same as they were. I am also aware that your fuel in USA is pretty crap as I have read of it and I have seen Top Gear a UK car show to re test HP output of some of your cars on better UK fuel to find an increase,
I am in Thailand and I am being pushed towards e fuels whic is Ok but does seem to have different calorific content. I can run E 20 ok but if I dope it with a bit of deisel it is better. Theory is I suppose that a slower burn and a longer power stroke rather than a quick bang. I have a Royal Enfied that loves a deisel mix up to approx 20%.

With this in mind I wonder if the float level should be lowered a bit, I do find that the speed of idle increases when the fuel is turned off.

If the manual was written for the USA market it might not be correct for better fuels.

Im going to lower my level about 2 mm each carb. I might consider lowering the rear carb 3 mm to accomodate the higher delivery pressure for the head of the fuel +pump pressure.

I had thought about using the pump for the front carb only as that is the only one that needs it.

Ille get back, later

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WintrSol
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Re: Float level and E fuels

Post by WintrSol »

The fuel level helps control the fuel/air mix, so lowering the levels would make the engine run leaner. Leaning out at idle will cause an increase in rpm, as the expense of ride-ability. The bike won't pull away from a stop the same way, as it could cause a big flat spot when you start to open the throttle, and the rpm will 'hang' when you release the throttle, then drop to the set idle. Running lean makes an engine run harder, and hotter; engines used for drag racing are tuned lean, but then, they aren't expected to run a lot of miles. Which is the negative side of running lean - it slowly burns up the engine from the inside out. I've yet to read anything about e fuels needing a different mixture, but, for now, we have E10; higher percentages are coming to us, though, which may reveal any need for mixture changes.
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Re: Float level and E fuels

Post by jonnycando »

The problem with E20 is it may already run leaner than e10, so lowering the floats will only exacerbate the issue. DO check your manual, for it may not even recommend E20. If you've no choice, replace your fuel lines with modern ethanol compatible ones. And be prepared to do regular carburetor kits as the rubber bits dissolve repeatedly, unless modern repair kits include upgraded soft parts which is entirely possible. Also use a ethanol fuel treatment religiously. Ethanol absorbs water, and the more available the more it soaks up. A humid environment would really make it an issue. The inside of your tank would rust away fast without fuel treatment. Of course you could also get the tank lined with the same stuff they use to fix a rusted up tank. It probably works even better before the tank has rusted!

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Fred
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Re: Float level and E fuels

Post by Fred »

jonnycando wrote:The problem with E20 is it may already run leaner than e10, so lowering the floats will only exacerbate the issue. DO check your manual, for it may not even recommend E20. If you've no choice, replace your fuel lines with modern ethanol compatible ones. And be prepared to do regular carburetor kits as the rubber bits dissolve repeatedly, unless modern repair kits include upgraded soft parts which is entirely possible. Also use a ethanol fuel treatment religiously. Ethanol absorbs water, and the more available the more it soaks up. A humid environment would really make it an issue. The inside of your tank would rust away fast without fuel treatment. Of course you could also get the tank lined with the same stuff they use to fix a rusted up tank. It probably works even better before the tank has rusted!
The engine runs very well with 30 and 11,5 it seems less harsh but I am willing to accept this could be my imagination. Yes a lean engine is not good and even dangerous if you are emotional about your piston crown. The Jag XJ 3.4 would often burn out number 6 like a cigarette burn right through the centre ,-- a common prob when shutting off to leave a motorway. Only on the 3.4.
We have had e fuels here for some time and as I said I can live with it with doping with diesel this will help in protecting the tank and fuel lines are replaced regularly. This has been on going on for at least 5 years now.

So 30 and 11.5 has not been road tested but Idle is fine and seems good.

The 87 intruder was designed long before e fueI and am willing to believe that a diffrent fuel float level today would be published.

I am aware of the comments you made.

The ideal ratio of 14.7 is a ball park figure, I am not trying to make breakthroughs in combustion chamber management, but if these fuels are more volatile than a ratio of less that 14.7 may well be tolerated.

The internet holds many examples of plug specialist accepting that a modern fuels leave a darker colour as did the old lead fuels in the past.

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Re: Float level and E fuels

Post by WintrSol »

Ethanol is less volatile than many of the components of 'pure' gasoline, which is why it raises the octane rating, and takes longer to burn.
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Fred
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Re: Float level and E fuels

Post by Fred »

WintrSol wrote:Ethanol is less volatile than many of the components of 'pure' gasoline, which is why it raises the octane rating, and takes longer to burn.
Yes I agree thats what they say dont they. However in my experience with what I buy here and Malaysia it is not appearing to be the case , hence this posting.

My Royal Enfield 350cc Iron barrel runs beautifully on a 20% deisel mix. I will go out of my way to get some. I can easily tell if it is in the fuel or not. I pulls much better than normal fuel and is most certainly not my imagination. It has a lovely slow idle too.

Theory is I feel that the doped fuel takes longer to burn. The RE is only 8:5 :1 and the longer burn gives a longer power stroke making an increase in torque. Dare I say the difference is magical.

It is on this experience that I have decided to make some tests of my own well play tests really.

My little Suzuki Crystal 110cc 2 stroke does not enjoy the deisel mix as much and will smoke. However there is an increase in toque but no where near the same as the RE. The Re does not smoke at all.

These test are not just a blast round the house but a full tank of fuel used in exactly the same way as normal on exactly the same route home and the same hills. I have been using deisel in the RE for 2/3 years.

In the old days manufacturers would make a combustion chamber to run on the fuel available, ( Probably from the war) now e have the cheapest fuel possible mixing with ethenol, alcahol ( same) , palm oil, corn oil, just to pay the share holders.

Those of us who run older vehicles have already needed to change valves and seats to run on this hotter fuel and will have to do some experimentation

It seems logical to me that valve burning fuel could be made more old vehicle accommodating by doping. Some already have made a lead additive substitute.

BUT if E 20 is supposed to have less calorific content then why is it burning valves of old engines, They say the lead lubricates the seat well I think my deisel works the same.

I do have some diesel in the 1400 as I type but only about 5%. At present it is not noticeable except for a lovely stable idle which I can not 100% state as a consequence as I have 30 and 11.5 float level now..

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Re: Float level and E fuels

Post by WintrSol »

I don't know what Diesel fuel mixed into gasoline will do on our engines, even gasoline with ethanol. Diesel is a slightly heavier, similar to what we call kerosene and the Brits call paraffin. Seems like it would work like a fuel system cleaner or top oil; it certainly will burn more slowly than gasoline or ethanol.

As far as valve seats go, Honda has used hardened seats since at least 1965, and most other engines made for the US market since lead was removed from our gas in 1996. Many engine makers moved to hardened seats for engine life around the same time as Honda, as people grew tired of lapping valves every 20000-30000 miles or so.
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Fred
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Re: Float level and E fuels

Post by Fred »

Ok --returned to 27.7 and 9.1mm It had a nice idle but did not want to increase in revs seemed hard work for it to rev but twist enough and it would just did'nnt seem to want to--response is the word I suppose.

Any way not a prob, nice way to spend a Frid afternoon, I got a radio. all back to normal again.

Ill see how much deisel it will take before it splutters out any bets?

Ive had 20% in it before and it started like a radial engine cough splutter bang untll it warned slightly then humbed.

The banging from the pipes was serious it sounded like I was in a chinese fire cracker show. :lmao:

But when warmed up it was fine.

I think diesel keeps the carbs in good condition also like redex upper cylinder lubricant in the 60's.

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