I just returned from a 1,200 mile trip on my 05 Drifter 1500 that took me through the hills of WV and VA. I noticed a lot of spark knock on acceleration at speeds of around 75 mph and up while pulling up long grades. I had to either allow my speed to drop off or run it in 4th gear to prevent the pinging. I used 93 octane throughout the trip. At the half way point, I bought a can of Sea Foam and put about 1/3 of it in the tank at the next three fillups without any change in the detonation/pre-ignition. I pulled all four plugs after the trip and they all have a nice light tan color. Spark plugs are NGK DPR6EA-9. Cooling system is full and seems to be working OK. Cooling fan cycles as it should when parked and idling. The bike just turned 10,000 miles this weekend. Any ideas?
Overheating, possibly? Hot heads will detonate before spark. Did it seem like it was hot at all?
It didn't seem like it was running hot. The cooling fan cycled normally when parked and running. Temps were close to 90F on Friday but Monday they were in the high 70s & low 80s. Detonation was the same.
Mine does that, too if I pour on the power above 75...below that, it doesn't. Most people believe pinging happens in low speed/high load situations, but I'm thinking that this has more to do with airflow through the 4 valve heads. I can get it to do it in 4th if I run much past 90 with the throttle wide open, too. High airflow might be signaling a transitory lean condition. I never noticed mine doing it until I modded the intake to let in much more air...
A little knock is pretty harmless but detonation will ruin your motor in short order. I can hear my motor over the exhaust and it sounds like it has a little knocking, but I'm sure that's normal kawasaki power knock and your describing something more serious it seems. I've got no clue what could be wrong, I wish I could hear it. Bad Gas?