Pinging on hard open throttle

[Bohdan]

I have noticed that bike runs OK on 89 gas, but if throttle whacked hard open from start then there is moment of engine pinging. I changed to 93 - all is gone.
Triumph states 89 octane should be OK... Is it because they started to add 10% alcohol to fuel in here? Any opinions?

[Goffe]

I assume you don't use cheap brands of gas. Also, assuming it's still under warranty, you could have the dealer look at it. It shouldn't ping. I haven't found the 10% ethanol to be a problem.

[Night Train]

It could be the gas. But, yes it should run on the lower octane. Personally, I use high octane all the time. Not because I think it will run faster but worry about pinging especially when it is hot out.

[Bohdan]

I use Shell normally, sometimes BP (Amoco). Bike was just at dealers for dual Arrow exhaust fitted and dyno. This eliminated popping on deceleration completely. Pinging was there before and did not change after dyno.

[VWTim]

Mine does this too. But with 92 octane, only when the engine is warm and heat soaked. Because of that I'm not worried and figure a tune when I swap exhaust should fix it up.

[Bohdan]

Well, I found kind of answer in the owner's manual:
"If 'knocking' or 'pinging' occurs at a steady engine speed under normal load, use a different brand of gasoline or gasoline that has a higher octane rating."
So it seems that Triumph is aware of it and thinks it's OK...
I guess I'll keep using 93 octane. Won't hurt anyway.

[29932]

I used to be an aircraft mechanic and what you are describing sounds to me to be "detonation." That would explain your “pinging.” The bottom line…..use the octane fuel rated for your bike or auto. Some of the stuff mentioned below is of course worst case scenario. Here is the text book definition out of my aircraft powerplant book. I know this is out of an aircraft book but it applies to motorcycles to. Thought you guys might find this interesting:

Detonation is caused when the temperature and pressure of the compressed mixture in the combustion chamber reach levels sufficient to cause instantaneous burning (explosion) of the fuel-air mixture. Excessive temperatures and/or pressures can be caused by several different engine parameters, such as high inlet-air temperature, insufficient fuel octane rating, excessive engine load, overadvanced ignition timing, excessively lean fuel-air mixture and excessive compression ratio. A principal cause of detonation is operation of an engine with either a fuel whose octane rating is not sufficiently high for the engine or a high-combustion-rate fuel. A high-octane fuel can withstand greater temperature and pressure before igniting than can a low-octane fuel. When detonation occurs, the fuel-air mixture may burn properly for a portion of its combustion and then explode as the pressure and temperature in the cylinder increase beyond their normal limits.

Detonation will further increase the temperature of the cylinders and pistons and may cause the head of a piston to melt. Detonation will generally cause a serious power loss. Instead of the piston receiving a smooth push, it gets a very short high-pressure push, much like the head of the piston being hit with a hammer. This high-pressure push occurs too quickly to be absorbed by the piston, with the result being a loss of power. Detonation will result whenever the temperature and pressure in the cylinder become excessive. A very lean mixture will tend to burn at a slower rate than will a rich mixture, allowing the cylinder to be subjected to high temperatures for a longer time than usual. If this condition is not corrected, the cylinder temperature will continue to climb until detonation occurs. Detonation can also be caused by excessive intake air temperature.