Hey GTAM,
I have a problem with my bike and am hoping for some guidance on where to start looking so I don't waste too much time/money troubleshooting.
I've got a 2001 CBR600F4i with 30,000km, purchased used, the only known history being a new CCT and valve adjustment both of which were done since purchasing.
The motor sounds great and the valve train is very quiet. Until yesterday, midrange power felt excellent to me!
The issue is a complete loss of power at WOT anywhere over 10k rpm. At partial throttle the bike will rev freely, but at 3/4+ throttle it will simply stop revving above 10k. It is not a jerky loss of power like a rev limiter, but very smooth and it will just maintain that rpm until I back off the throttle halfway then it will continue to rev. It is not just a temporary dip in power delivery, it will maintain that rpm indefinitely. If I gear down to bring rpm anywhere in the upper range, as soon as I twist the throttle it stops making power, so it's not right at 10k but anywhere above. The issue is also getting worse, yesterday it started happening at a lower rpm to the point of affecting the midrange for the first time, and then on my final route home it wouldn't make any power over 6k, highway riding was nearly impossible! I will add that in neutral with no load it would always rev freely, but yesterday when I got home it would not even do that anymore stopping around 8k or so.
My first suspicion is fueling or fuel pump. I will be pulling plugs for inspection and measuring exhaust temp on each cylinder as well. I will be checking the airbox etc. for blockage, pinched hoses, since it's easy to do. Bad timing is a suspicion, but not my first, that would result in poor performance but not a complete lack of. I also think this issue was happening before I had the work done. The reason I don't know for sure is because I never pushed the bike hard prior, but the one time I did I felt hesitation at high rpm but didn't think much of it since the bike was going to the shop in a couple days.
Thanks for any tips.
Jeff
I have a problem with my bike and am hoping for some guidance on where to start looking so I don't waste too much time/money troubleshooting.
I've got a 2001 CBR600F4i with 30,000km, purchased used, the only known history being a new CCT and valve adjustment both of which were done since purchasing.
The motor sounds great and the valve train is very quiet. Until yesterday, midrange power felt excellent to me!
The issue is a complete loss of power at WOT anywhere over 10k rpm. At partial throttle the bike will rev freely, but at 3/4+ throttle it will simply stop revving above 10k. It is not a jerky loss of power like a rev limiter, but very smooth and it will just maintain that rpm until I back off the throttle halfway then it will continue to rev. It is not just a temporary dip in power delivery, it will maintain that rpm indefinitely. If I gear down to bring rpm anywhere in the upper range, as soon as I twist the throttle it stops making power, so it's not right at 10k but anywhere above. The issue is also getting worse, yesterday it started happening at a lower rpm to the point of affecting the midrange for the first time, and then on my final route home it wouldn't make any power over 6k, highway riding was nearly impossible! I will add that in neutral with no load it would always rev freely, but yesterday when I got home it would not even do that anymore stopping around 8k or so.
My first suspicion is fueling or fuel pump. I will be pulling plugs for inspection and measuring exhaust temp on each cylinder as well. I will be checking the airbox etc. for blockage, pinched hoses, since it's easy to do. Bad timing is a suspicion, but not my first, that would result in poor performance but not a complete lack of. I also think this issue was happening before I had the work done. The reason I don't know for sure is because I never pushed the bike hard prior, but the one time I did I felt hesitation at high rpm but didn't think much of it since the bike was going to the shop in a couple days.
Thanks for any tips.
Jeff