Full Version: What Octane fuel do you run?
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Had a Tank full of 87 octane and started to hear the tapping/pinping noise from the engine,switch to 89 octane and the noise is now gone. Was wondering what fuel you guy's run?
I run em all... For the long highway trips I use 92 octane to get the smoothest running... For the local stuff I use 87 mostly with ocassional 89 tanks...
I run 87 octane all the time, the only difference i notice when I use higher octane is the cost.
I do and always have put in regular unleaded gas (cheapest)
The handbook does say anything over 86, and if it the engine knocks either change brand or raise the octane ratiing
Regular 87 octane gas with a little Marvel Mystery Oil added to every other tank full. The only time I switch is for high altitude and then it is a lower octane as blended and sold at those higher elevations. Never had a problem in over 175K miles with knocking or pinging. Buying anything over 87 octane is a waste of money in my opinion.
I run 87 all the time with no problems. I did use a tank once of that 85 ethanol crap they sell in Washington. Made the bike run terribly. Every third or fourth tank I add a measured amount of MMO.
Budman Wrote:Had a Tank full of 87 octane and started to hear the tapping/pinping noise from the engine,switch to 89 octane and the noise is now gone. Was wondering what fuel you guy's run?

Sounds like you might need to clean the carbon out of your engine. Since most GL1200 don't run their Wings like a drag race bikes it is very possible to accumulate carbon in the combustion chamber and valves. I have actually seen some GL1200 valves caked up with carbon and other deposits so bad that it actually interfered with airflow through the head. G.M. makes a chemical called top cleaner, you pour it into the intake until the engine stalls, let it sit for 20 minutes then start the bike and watch the smoke show. Repeat until the can is empty and this will do a really good job of removing most of the carbon.

I always use regular grade 87-89 octane in my bike even with the performance engine because the GL1200 is a low compression engine. If you knew the physics of flame front and flame travel you could understand how regular grade fuel would deliver more power and better fuel economy in the GL1200 engine. Regular gas burns fast and premium gas burns slow and since the GL1200 was designed for fast burning regular grade gas then it will run best with regular gas. You are not doing the GL1200 engine any favors by running premium gas and in fact the engine may run hotter out the exhaust because the slow burning premium gas is still burning as it goes out the exhaust whereas the regular grade gas will have done its job and pushed the piston down all the way and the flame goes out whereas the premium will still be burning, wasting its energy. Now, up the compression ratio and then you will see an appropriate application for premium gasoline.


Right on Vic, a lot of people dont seem to understand the octane thing at all. Premium should be a total waste in a wing. 8) 8) 8)
I run 87 octane and have never had a problem..........Vic was talking about GM having that top end cleaner, well: when i worked for napa in outside sales,my first introduction was to go out with the "Seafoam" rep and demonstrate to our customers its benefits first thing we did was pull a vacuum line from the brake booster and dribble seafoam into it till the motor ran rough and or shut off,then let it sit for 10 or 15,poured rest of 16oz can into gas tank ,on restart the motor will smoke alot for a couple miles (tip: startup and run it to death for a couple miles,leaving a trail of smoke) :lol: :lol: makes everybody think u have a problem,what u are doing is cleaming the gum and carbon from the valves and pistons

this could be a good thing to schedule on a club maintenace day

this is basicaly what some shops are doing with their fuel injection cleaning routines they charge $75 to $100 for, but they have to buy the machine and the chemicals ,their profit is about $50/car
just realized that the reason that alot of the people are probably having the pinging is because they do have the excess carbon buildup which has raised their compression ratio "synthetically"
thus making them think they need high octane fuel when all they need is to clean out the carbon buildup
I've run Premium: 91 octane ever since I got the bike running except last year during the "gas shortage". While I was in and coming back from Georgia last year I had to use 87 octane in my bike. The result's were less than stellar as the bike pinged and had major valve clattering under medium to heavy acceleration. After I got home I went back to Premium and had no further problem's.

I'm gonna try the suggestion's in this thread, BUT,,, I find it hard to believe that my bike is carboned up enough to raise the compression to require high octane fuel with only 28,255 on the odometer......
u might also check that the timing is dead on,advanced timing will result in pinging

if you dont occasionally get on it hard it will carbon up or if you have an oil consumption problem,any one of these things can help to compound the problem


Thank You all for the reply's. Maybe I should go back to 87 octane and take the bike up on I-75 and run her at 70 mph to blow anything (Carbon ) out the pipes. She only has 63K miles on her. The Timing is Dead ON so I know it's not the timing.
if you are only going to go 70 make sure u keep it in 2nd gear :roll: :roll: :roll: :roll:
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