By mistake, habit really, when I first bought my '07 RK I filled up with Regular on the first tank. Ran like ****. Asked around was told yea dummy don't do that use the good stuff. Did that and it ran fine. 2 tanks later same dumb mistake again. Next time I fill-up with Prem and everything is fine. I will not make that mistake again.

 

Guys keep recommending octane boost...Save your money.

It does not work the way you think. If the bottle says it boost your octane by 5 points, that means your 87 with be 87.5, not 93 octane.

FWIW, my bike runs just fine on 87.

 

The whole point of using higher octane fuel is to ensure the gasoline doesn't ignite prematurely (pre ignition). Modern EFI systems sense pre-ignition and will compensate thereby reducing the need for octane boosters in a pinch and thus you may get away with it. I disagree with the previous poster that octane boosters don't work but certainly there are several out there that don't live up to what's claimed. Again the key is to prevent pre-ignition and a good additive will have this effect when used correctly. Another ounce of caution if you pump the wrong gas into your tank is to lay off the throttle and put 91 octane in before the tank really needs filling. Adding the higher octane fuel definitely will raise the overall octane level of the fuel in the tank.

Another thing to consider if you are tempted to use a lower octane is that while your EFI may compensate, it can be a false economy as the engine will no longer be optimally timed to achieve the best efficiency. Anti knock compensation really is intended to prevent engine damage, not to allow you to use the wrong octane gas on a regular basis. Good advice for all internal combustion engines is to use the recommended octane for the engine per the manufacturer. Of course if you modify the engine substantially it's important to change the fuel to match the modifications. Lack of availability of higher octane fuel is one reason not to get carried away with compression modifications.

 

I used regular for one tank with no problems, so then i did two tanks. Then after about the fourth tank, the check engine light came on. Switched back to high test, and after the 50 start/stop cycles the light went off and has never came back on.

 

During hurricanes we have run short on gas at times in the Panhandle. I have run regular unleaded for limited amounts of time without any noticed problems but have switched back to Super Unleaded as soon as it was available again.

 

I've run nothing but regular for years and never heard a ping. Of course my idea of going wild is cracking it anywhere past half throttle.

 

Have had to use regular a couple of times in Alberta and more than a couple in Saskatchewan and Manitoba when passing through. Knowing what the higher octane was for I simply avoided aggressive acceleration and roll-ons. No problem. Always then put premium in as soon as possible

 

I'd be interested in knowing what mpg you get with regular vs. premium - although that's hard to measure unless you do it over an extended period of time.

Another consideration is that as you get a bit of carbon build up - and you doubltless do have some, your compression has actually increased a little.

 

As an ex-USCG Engineman, I'd doo-doo on that idea. Not a good way to boost your motor.

 

Below is the guideline for the minimum octane rating to use based on compression ratio. Cam type is also a factor, taking into account early valve closing on some cam designs may also require higher octane.

Compression Ratio / Octane Rating: 7:1 / 85 8:1 / 87 9:1 / 91 10:1 / 93 11:1 / 96