[caspianthruxton]

I use 92 or 93, but i sometimes wonder if i should use regular. Any suggestions?

 

[Spyder94]

On 2006-11-05 14:43, caspianthruxton wrote:
I use 92 or 93, but i sometimes wonder if i should use regular. Any suggestions?

Do your have any pre-ignition Noise? I not run the low octanane fuel.

Steve Gear Head At Large :-D

 

[caspianthruxton]

the only problem i ever have is that sometimes when i clutch it and give it some gas to rev match it kind of chokes out for a second.

 

[KAH24]

There is no scientific logic to back it up, but I've used Chevron Supreme 93 Octane in every motorcycle that I have owned. Now that I think of it, I've only used Chevron gas in my cars/trucks over the years as well--dating back to '88

I became a Chevron fan back in 1988 during my senior year in HS when I put a bottle of their Techron fuel injection cleaner in my first car--a black 1987 VW GTI, 1.8l dohc 16v, that made a whopping 123bhp (crankshaft I'm sure). In my 17 year old mind, it made a difference--in my wallet I suppose. I guess it still makes a difference to me as I still use their Techron additive in my cars/bikes and their gas.

Sorry for the trip down memory lane, but to your question--I suppose that the Thruxton could run just fine on 87 octane as the owner's manual doesn't specify premium fuel. My other bikes specify premium fuel, so I just put the premium in my Thruxton as well. :-D

 

[AVMECH]

The manual for the thruxton recomends 89 octane minimum fuel. I would think that by running anything less, you will run the risk of preignition and detonation. mabey it would be fine in certain temps and such, but if you have ever seen a piston destroyed by detonation, you would think twice. As for running a higher octane, I don't believe that there is any need for it. Octane really means a resistance to detonation and if your motor dosen't have the higher compression ratios or higher temps requireing a higher octane fuel, you are just wasting money. I run 89 at all times in the 95 degree Louisiana summer and have never had any problems. You will not get any performance boost by using a higher octane fuel. There is a thread about this on modifications and workshop talk titled off the oil thread and onto fuel if you want more information. Here it is
http://www.triumphrat.net/modules.php?op=modload&name=Forum&file=viewtopic&topic=61005&forum=7

 

[ThruxtonMI]

i use 89 octane as specified in the manual. higher octane gas than that is just a waste of money.

 

[monkeyboy]

I ride mine daily, in traffic, to work.

I run 91 in mine, simply because it's an aircooled motor with no fan to help cool it. I don't wan't it to get any hotter than it has to in traffic.

Especially because I don't have a temp guage to tell me to pull over and let it cool off.

 

[robnobrakes]

Since I had the head skimmed and gas flowed (compression ratio now 10.4 to 1), airbox removed etc. I now run mine on 99 super unleaded from Tesco (supermarket chain) or the super unleaded available from Shell or BP, both of which are around 98 I think. The bike runs like a dream, quick too (70 rear wheel BHP).

 

[setts]

Just to confuse everyone I run 95 unleaded. But that's RON. Robnobrakes says he is running 99 unleaded and in the UK they also use the RON rating. As I remember you guys in the US use the PON rating or variations there of. Somewhere the is a table that compares RON , PON et al. Essentially the petrol is fairly equivalent it's just how it's measured. Distance is universal, but you can measure it in miles or kilometers...

 

[markbvt]

FWIW, I used to run mid-grade in my Bonneville, but I began to notice some detonation when putting a load on the engine (such as accelerating hard uphill). I switched to premium and have had no detonation since. (It used to run fine on mid-grade -- I attribute the change to my TORs packing out a bit, as they're definitely louder now than they used to be, so presumably my mixture is slightly leaner.)

--mark

 

[sweatmachine]

89, I had to use 87 once because I was in the middle of the desert and it's all they had. Sometimes I use 91 if I'm riding with my sportbike buddies and we all fill up together.

Usually 89 though. No probs.

 

[FlatFourOne]

Wow, so higher octane doesn't mean more power? What's the point of a higher-octane fuel? Isn't it cleaner? I just use premium octane (91) here in Oregon since that's the highest octane you can get. I also use it in my car since I was under the impression that it burned cleaner and provided a bit more power. Is that not so? Someone school me!

 

[AVMECH]

A higher octane fuel does not mean more power. As a fluid is compressed, (yes, air is considered a fluid) it's temperature increasses. The octane rating of a fuel is basicly a mesure of it's flash point, the temperature that it ignites. The mixture heats up as it is compressed and the spark ignites it at a point that it will make a slow, even burn, gradually increasing cylinder pressure as the piston rounds TDC, and expanding pushing the piston through the power stroke. To low of an octane fuel can cause preignition, when the fuel combusts from compression before the spark, causing high cylinder temperatures and ruining your exhaust valve as the superheated gasses exit (and in extreem conditions, I've seen it, turning a motor backwards), or detonation, when the spark ignites the mixture in a sudden, violent explosion causing extreem, destructive force on the piston (imagine hitting it with a hammer rather than pushing it down with your hand). Using a higher octane fuel does not change to BTU rating of the fuel, so power remains the same. It simply changes the temp at wich it will ignite allowing it to burn evenly in a higher compression or hotter running motor. I hope that this answers your question and saves you a few bucks at the pump, FlatForOne. Everyone else, sorry for the textbook but he asked to be schooled.

 

[FlatFourOne]

AVMECH, Thanks for the answer. That's very interesting. So, I would assume that unless you are running a high-compression engine, you can stick to whatever the manual says to use? The Thruxton requires 89 or higher, correct? Thanks again! That's great info.

 

[AVMECH]

Yep, 89 or higher. There is someone on this forum who skimmed their cylinder head and increased their compression ratio, and they might want to use a higher octane gas. But for me, 89!

 

[4Triumph]

Yup, I got used to pulling all the way to the last pump on the right with my BMW! Guess old habits are hard to beat, my new baby is spoiled and only stops at the last pump at the gas Island, she love's it so! Thruxton's aren't hard to please so long as you feed them right!

 

[Guest]

When I bought my 04 Thruxton I asked the dealer specifically about this. He said the engines are designed for regular so run the regular. He mentioned there was no advantage to putting in higher octane. He also owns a thruxton so I trust him.

 

[CYNCRZR]

Someone told me that the dealers blend 87 & 91 in the pump to make 89. They also said 87 is most likely the freshest fuel available because it turns over the fastest.

I run 87 in the winter & 91 in the summer when i get's over 100. FWIW!

I have a question though: does the 10% ethanol they put in CA. gas mean it burns cooler cuz ethanol doesn't create as much energy when combusted ?

 

[TonyThruxton]

Is it just me, or did any of you guys get a lump in your throat or a weird feeling in your stomach seeing Caspianthruxton's name again on the first page of the screen when this theard was brought up again?
RIP.
TS

 

[test-reg]

On 2007-01-31 17:18, TonyThruxton wrote:
Is it just me, or did any of you guys get a lump in your throat or a weird feeling in your stomach seeing Caspianthruxton's name again on the first page of the screen when this theard was brought up again?
RIP.
TS

Yeah, RIP TJ!