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Author Topic: Fuel grades, additives and performance.  (Read 3252 times)


  • Bulleteer
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Fuel grades, additives and performance.
« on: September 23, 2011, 02:04:57 am »
My last two fill ups have been with premium petrol (I just thought I would see what happened compared to normal petrol). I also bought a little bottle of valve saver/upper cylinder lubricant and added that to the fuel.

I am not impressed.

Maybe its coincidental, but I am getting a lot of hesitation from the engine at higher speeds. The engine occasionally seems like it wants to cut out and it sometimes gets little farts/backfires. I can't tell if they are coming from the carby or the muffler. I used to be able to get up to 100kph on the flats but now I am maxed out about 95.

Urban myth in my area is there is a lot of water in the fuel hereabouts, maybe, maybe not.

I have put about 1500 k's on my bike since I got it in June and I haven't noticed this problem before I put the premium fuel and valve saver in.

I was under the impression that premium fuel and valve saver would do no harm and may even help things. I wonder now.

Opinions please


  • Black C5
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Re: Fuel grades, additives and performance.
« Reply #1 on: September 23, 2011, 12:21:39 pm »
Bottles of "snake oil" don't usually fix mechanical or electrical problems. Use of high octane has been covered before but the short version, high octane prevents knock, ping, preignition etc. If that is not your problem, high octane simply wastes money.

Under high load and high speed ignition can break down. Change the plug. Look at your plug wire at night with the bike running. You may see spark leakage. Check ignition timing. Next you want to be sure your valves are properly adjusted. Check the air filter. Check the intake for leaks. Check the compression.

Those are the basics. If you suspect water, you can filter the fuel through a chamois. Unless you get your gas from a rusty 55 gallon drum, water is not a very likely suspect.


  • Grand Gearhead
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Re: Fuel grades, additives and performance.
« Reply #2 on: September 23, 2011, 01:28:35 pm »
I never use premium fuel in any of my vehicles, use real gas whenever possible (no alcohol) haven't had any problems, no pinging or knocking. 

I have tried fuel injection cleaner a couple of times in my Chevy truck and both times the check engine light has come on with 2 days.   Have never had any luck with radiator sealer or any other kind of snake oil.

These are just my experiences, your actual experiences may vary.

Best of luck to you.   ;)
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2011 Triumph Bonneville T100
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Lwt Big Cheese

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Re: Fuel grades, additives and performance.
« Reply #3 on: September 26, 2011, 04:37:15 am »
I have a glass bowl type of fuel filter.

If there is any water you would be able to see it in the bottom of the bowl, and any sedimant.
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bob bezin

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Re: Fuel grades, additives and performance.
« Reply #4 on: September 26, 2011, 12:13:46 pm »
have you checked your air filter?
2000 RE classic ,              56 matchless g80
2006 RE delux fireball       86 yamaha SRX 600                       
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Re: Fuel grades, additives and performance.
« Reply #5 on: September 26, 2011, 02:37:58 pm »
The premium fuel should not have caused any problem whatsoever.
As was mentioned by olhogrider, the high octane fuel has things in it to prevent pre-ignition from high compression engines.  You don't need it and buying it is a waste of money.

The "valve saver" on the other hand may have fouled your spark plug.

There are several reasons things like "valve saver" can cause problems.

First, most of the fuel additives are made for use in cars which have 10+ gallon gas tanks.  It is real easy to put in too much when your bike's gas tank only holds a few gallons of gas.

Many of these additives are no more than light weight motor oil so by adding them you are forcing your engine to "burn oil" which will create carbon in the combustion chamber.
As I mentioned above, it can also cause fouling to develop on your spark plug, especially if you added too much to the gas tank.

There are several additives that will also add solutions containing various metals and these too can foul spark plugs and cause buildups in the combustion chamber and on the valves.

To say I'm not a fan of most of these is an understatement.  The only thing they help are the profits of the companies that produce them.
Also, IMO, there is absolutely no reason to "lubricate" your valves.  They get more than enough when the engine is running.

A good brand of fuel Injection cleaner on the other hand, will work to fix plugged injectors but if you are buying your fuel from a major brand company there is already enough injector cleaner in the gasoline to prevent problems.  All of the Big oil companies add it.

On my K-75 Beemer I did have an injector problem because I always bought the cheapest gasoline I could find from small independent gas companies.  Part of the reason they could sell it so cheaply is they didn't add any injector cleaners at all.

Anyway,  the Beemer had pauses and hesitations and became very hard to start.
By adding 1/4 of a bottle of Chevron fuel injector cleaner with Techron to an almost full tank of gas, within 10 miles of riding the misfires, pauses and hesitations the bike was having went away.  It became easy to start and ran like a champ.

I can't speak for other brands of fuel injection cleaner because after my good luck with the Techron that's all I ever use in my fuel injected cars.

If my G5 ever starts acting like the injector is plugged I'll use a little bit of it in it too.

As for the idea of adding fuel injection cleaner every time you fill up, don't bother.
It's cheaper to just buy gas from a Major oil company and considering how small a motorcycle gas tank is and the excellent gas mileage it gets there's no good reason to 'skimp' on buying good gas.
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Re: Fuel grades, additives and performance.
« Reply #6 on: September 26, 2011, 03:26:25 pm »
 Our bikes engines will make no extra power with high octane gasoline unless the compression ratio is raised.

 Bear in mind that where over here in the US our motor fuels have been reformulated by government mandate and without a specific recipe and it differs from place to place.

Modern gas burns o.k. in a computer managed auto but with poor economy.
It is LOUSEY in a carburetted engine.

 High octane premium has less paint thinner, asphalt, solvents, industrial waste, ethanol, etc. than the lower grades.

 Using it in my Bullet only gives easier starting and smoother running, no power gains at all.

 My county has some of the worst concoctions but the situation is improving somewhat.

 The two fuel additives I have found satisfactory are Marvels Mystery Oil and Sea Foam.

 The MMO used sparingly provides some valve and upper cylinder lubricant and the Sea Foam is exception at reducing carbon accumulation with the garbage fuel local to me.

I can break it better,,,,at night, in the rain, on the trail,, 20 miles from nowhere.

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"TIMEX", the '06 Iron Barrel Military that takes me everywhere I want to go... and some places I shouldn't.


  • Bulleteer
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Re: Fuel grades, additives and performance.
« Reply #7 on: September 28, 2011, 12:23:24 am »
Thank you so much, that was very educational!

My bike is a iron barrel with a carby, kick only. I almost bought a B5, but I decided to go for an engine that I would be able to do some repairs to myself.  I live in a country town in Queensland and the nearest RE dealer is  3.5 hours drive away.

But back to the topic,...the consensus then is that I am not getting the benefit from premium fuel in my stock engine and should just stick with regular unleaded.

And ditch the valve saver stuff.

Many thanks


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Re: Fuel grades, additives and performance.
« Reply #8 on: September 28, 2011, 11:50:23 am »
Actually, you may get more power out of the lower octane straight gas as it has fewer additives and more real fuel. Only run the octane you need to prevent preignition for the best results. This is not just my opinion. Drag racers used to prove this back when all gasoline was gasoline.
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