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Premium Shell or BP is what I try to keep in my girl but if you are in the middle of no fucking where California, 87 works too.:D
 

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Premium Shell or BP is what I try to keep in my girl but if you are in the middle of no fucking where California, 87 works too.:D
Yeah, in a pinch! till you can get more premium gas back into the tank.

wondering if it would smooth out my fuelling any, if i go up to super
I think the octane rating system may be different for Polarbear in Scotland?

Our gas in the US is pretty sorry compared to what Europe and Australia get, from what I understand. But if we're talking about US gasoline, the service manual says 91 octane. The highest we get is 91 here in CA. So that's what I run.
Don't run a lower octane than what the manual for your country recommends. Performance will definitely suffer, your engine is built to run premium gas.
That gets me wondering, what's the stock compression on our bikes?
 

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As I recall stock compression is somewhere around 10.5, which isn't as high as it could be; but this depends on the cam durations too. The longer the duration (of open) the more compression - usually.

US & European Octane ratings are measured differently (I think it's detailed on Wikkipedia, etc. if interested), so the US rating show as lower than European, but the gap in resistance to pre-ignition isn't as much as most people think.
As an example I see Turbocharged performance cars that are meant to run in Japan on 100 RON & owned by US Military on bases here, be filled up with US 91 RON and they run just fine too.

But yeah, I still put in 100RON Japanese premium fuel in my bike all the time. It's about 6% more expensive but what the hell! The VFR & my other bikes run 95 RON regular. I believe the UK is 99-97 RON premium (Depends on where you buy from) and 95 RON regular.
 

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I have run 87 92 and 100LL(av gas)

I didnt notice any difference between them! I run 87 pretty regularly, No problem!
 

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I have run 87 92 and 100LL(av gas)

I didnt notice any difference between them! I run 87 pretty regularly, No problem!
+1 here, it all depends on the whole RON, PON,MON deal...i usually stay in the middle with 89 though. As for performance gains Id doubt you'd feel any w/ the higher octane.
 

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I could be wrong but I thought I read the RC will make more power with lower octane but will have detonation problems... I was short on fuel the other day so I put in a few gal of cam 2. I had the LB'S corked and noticed heavy bogging. Even after 4 tanks of premium it still has that sweet smell. Now she looks good, sounds good and smells good:D
 

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I could be wrong but I thought I read the RC will make more power with lower octane but will have detonation problems... I was short on fuel the other day so I put in a few gal of cam 2. I had the LB'S corked and noticed heavy bogging. Even after 4 tanks of premium it still has that sweet smell. Now she looks good, sounds good and smells good:D
:D Grape_ you take it to the next level LMAO
 

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What...lol
Actually that got me thinking of something.. I spent the last 4 days at the drag strip. The guy pitted next to us was running his dragster on alcohol. With it being slightly cheaper than cam2 and very cool burning I wonder what would be needed to run it in bikes.. I think its just a few different gaskets in the carb to switch over from gas in our motor. Seems like it would be awesome for track bikes...
Oh I didn't think it was possible but smells way better than cam2.... ok I might have a problem:)
 

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I could be wrong but I thought I read the RC will make more power with lower octane but will have detonation problems... I was short on fuel the other day so I put in a few gal of cam 2. I had the LB'S corked and noticed heavy bogging. Even after 4 tanks of premium it still has that sweet smell. Now she looks good, sounds good and smells good:D
Was it real "cam2" racing fuel? I heard sunoco bought them some years ago.

What...lol
Actually that got me thinking of something.. I spent the last 4 days at the drag strip. The guy pitted next to us was running his dragster on alcohol. With it being slightly cheaper than cam2 and very cool burning I wonder what would be needed to run it in bikes.. I think its just a few different gaskets in the carb to switch over from gas in our motor. Seems like it would be awesome for track bikes...
Oh I didn't think it was possible but smells way better than cam2.... ok I might have a problem:)
Alky is bad for everything in your bike ie: injectors, fuel lines, gas tank ect. and the only race gas i would ever run is VP U4.4 or MR12 but not without the proper tune since they are oxygenated, but plain racing gas is not going to pic up any hp and it cost alot more than pump gas.
 

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I'm lucky, I have about 4 stations here in town with 100% premium 92 octane. I only by ethycrap when I have no choice and then only premium for the bike.
 

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The sticker on the bike says 95 RON which converts to 91 octane. the Sunoco stations around me only have 87, 89, and 93, so I get the 93. if I really needed good gas, I'd hit up one of the marinas that sell non ethanol blended stuff. No 10% blend there, but there are only a half dozen or so in the state.
 

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As I recall stock compression is somewhere around 10.5, which isn't as high as it could be; but this depends on the cam durations too. The longer the duration (of open) the more compression - usually.
Compression ratio is based solely on the size of the combustion chamber relative to the cylinder displacement.

i.e. If the displacement of one cylinder is 499cc, and the combustion chamber volume is 50.9cc, then the compression ratio is (499+50.9)/50.9 = 10.8:1
 

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Compression ratio is based solely on the size of the combustion chamber relative to the cylinder displacement.

i.e. If the displacement of one cylinder is 499cc, and the combustion chamber volume is 50.9cc, then the compression ratio is (499+50.9)/50.9 = 10.8:1
Yes, that's true of course - but what I'm saying is that when running significantly longer duration cams, you need a higher compression ratio (Since your valves are open for longer to enable better breathing at high rpm).
My Yamaha designed 4A-GE engine runs 12:1 compression with 304 cams for example (Standard is somewhere around 9.5:1 on 256 degree cams).
 
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