you asked if we could cause damage to valvesKwee wrote: ↑Sun Sep 30, 2018 12:58 amAt low throttle position and WOTvcyclenut wrote: ↑Sat Sep 29, 2018 11:04 pm
was lean where? meaning what throttle position and rpm?
On your dyno results, the AFR WOT at 3k-4k is lean too
no way your causing damge to valves at 3-4k rpm's there isn't enough load or time to generate the heat to cause any issue.
I have also learned to not chase these spike in air fuel when you first rip the throttle open on the dyno. If the air fuel shown was the actual true air fuel at that point the power curve would sag big time.
I am not 100% sure why the sensor reads these fluctuations when you first rip open the throttle but it does. This is another reason to start the 100% throttle run so early in this case 2500 rpm, this gives the air fuel time to stabalize when it gets to the rpm's im really concerned about 100% throttle
The internet and social media has gotten eveyone so paranoid about burning up valves and even though its in my best interest to promote this idea that a bike thats a little lean will burn up valves i dont beleive it to be true. I live on social media and web boards. I can count on one habd the number of posts ive seen in the last 10 years about someone burning an exhasut valve and i would bet that they were more related to not enough clearnance on the cams not being lean.
We dont use leaded fuel anymore and valve seats are hardened. I really think this worry stems from back in the day when the leaded fuel was key to keeping valve seats healthy. When we switched from leaded to unleaded fuel cars and bikes started burning up valves. Then hardened vlave seats were introduced and its pretty rare now to hear about burnt vlaves.
I know a guy who had an intake boot rip casuing that cylinder to be so lean it burnt a hole in his piston. The valves and seats were still fine.