Who’d have figured?
While we were at Mosport, Bar mentioned that he had a can of C12 lying around that he wasn’t going to use; adding that in a sealed container the shelf life was almost unlimited. It was mine for the asking and he asked his wife to bring it over to the track on Sunday. In the interim, I bought some C12 at the track, so it wasn’t until the last session at Mosport that I started into Bar’s gas – which I then used in the Yellow Bike at the Calabogie SSR event.
And learned an expensive lesson in race fuel shelf life.
When Gary got into to the engine (shipped to him last week), he discovered evidence of detonation on the piston squish areas and in the top of the cylinders. The vertical cylinder wrist pin was broken and the piston cracked. The horizontal pin and bush damaged and the mains showing evidence of a pretty severe hammering. Had I not been running the WhisperJet Mk II muffler, the early signs of failure would have gone unnoticed and the results been catastrophic, so I guess I’m going to count myself lucky with the damage incurred.
With 13.4:1 compression and a pretty tight-to-the-limit squish, the motor required 110 octane to stay safe and we’d unknowingly gone down to 108 just switching to C12 and to God-knows-what with the five year old C12 that Bar gave me. Add track temperatures in the mid-90s F and you get hammered wrist pins and mains.
Remarkably with all these years hurtling around tracks on loud, fast Italian (and other) bikes, I’ve managed to avoid having to deal with ultra-high compression motors and race gas - and just wandered into a situation where I wasn’t fully cognoscente of my surroundings and the rules of the game. So, now I know much more than I did about the shelf life of race gas in plastic containers (measured in months, not years) and have firsthand knowledge when it comes to the dangers of detonation.
Gary’s going to put the motor back together with a more civilized compression ratio and to gain back some of the spice, the displacement will go up to 840cc. Kudos to him for dropping everything and jumping on the rebuild so I have a chance of making the Grattan SSR event.
Here endeth the lesson.
The Yellow Bike is based on a 1988 Ducati 750 F1. loudbike is a state of mind, a weblog about fast, loud Italian motorcycles and an internet store offering more vintage Ducati parts than you can shake a stick at.