Reply to thread

Message

<blockquote data-quote="2Wheels" data-source="post: 212104" data-attributes="member: 3804">Yamaha gytr power tunerLinks are all fairly worthless, just sales pitches.The tuner allows for 9 adjustment points for fuel and 9 for timing, at throttle openings and rpm's.&nbsp;The real meat of the issue for me I guess is the general mechanics of it.Most of the comprehensive information I have found online is car oriented and eludes to F1 technology with an asterisk, and being not bound by rules of conventional &quot;hot rodding&quot;, and that's really where I am most interested.. when the 250f is screaming along at 10k timing retard/advance would seem more critical, as the complete combustion cycle of the a/f mix takes the same amount of time to complete, but has less time to do so.What really sparked my interest was when I first rode the bike I felt a grin inducing surge of power from mid to top much like a 2stroke 250. I then got the tuner and seized the current map from the ecu finding +15% &amp; +18% fuel in that range and -4° &amp; -5° timing. The timing being retarded was a surprise, as I guess I was under the misconception that the higher rpm's would necessitate the spark being advanced to give it time to combust in the proper atdc range. Also, running race fuel with a 14.5:1 piston, again, cooler burn less detonation = advance time. So, I remap back to baseline stock settings. THERES the boring, predictable non-threatening 250f powerband I'm used to. I dicked around and created a few maps how I thought they should be, but just with mild changes to start with and just wore myself out riding and didn't switch maps often enough to get a real &quot;feel&quot; for what what did.I could get a high comp piston to run no eth 100 without detonation by retarding the time?Maybe the surge of power had more to do with the + fuel and the retard was just a safety measure?I'm fascinated by the whole idea.</blockquote>

[QUOTE="2Wheels, post: 212104, member: 3804"] Yamaha gytr power tuner Links are all fairly worthless, just sales pitches. The tuner allows for 9 adjustment points for fuel and 9 for timing, at throttle openings and rpm's. The real meat of the issue for me I guess is the general mechanics of it. Most of the comprehensive information I have found online is car oriented and eludes to F1 technology with an asterisk, and being not bound by rules of conventional "hot rodding", and that's really where I am most interested.. when the 250f is screaming along at 10k timing retard/advance would seem more critical, as the complete combustion cycle of the a/f mix takes the same amount of time to complete, but has less time to do so. What really sparked my interest was when I first rode the bike I felt a grin inducing surge of power from mid to top much like a 2stroke 250. I then got the tuner and seized the current map from the ecu finding +15% & +18% fuel in that range and -4° & -5° timing. The timing being retarded was a surprise, as I guess I was under the misconception that the higher rpm's would necessitate the spark being advanced to give it time to combust in the proper atdc range. Also, running race fuel with a 14.5:1 piston, again, cooler burn less detonation = advance time. So, I remap back to baseline stock settings. THERES the boring, predictable non-threatening 250f powerband I'm used to. I dicked around and created a few maps how I thought they should be, but just with mild changes to start with and just wore myself out riding and didn't switch maps often enough to get a real "feel" for what what did. I could get a high comp piston to run no eth 100 without detonation by retarding the time? Maybe the surge of power had more to do with the + fuel and the retard was just a safety measure? I'm fascinated by the whole idea. [/QUOTE]

Verification