Originally Posted by Steve in Sunny Fl
1) if the leo vince didn't drastically alter the way the bike ran when you put it on, it's probably OK to run with the flash. But understand "tweaking" isn't actually possible in the way you're suggesting. Without actual a/f ratio data, there's no way to know what the bike needs as far as fueling changes. If someone tells you he can just add or subtract fuel from the whole table and it will be good... RUN.
2) I can leave the limiter at 10,000, but WHY? the bike is making more power than stock and the extra revs won't help you drop into a stronger part of the power curve while shifting. as far as i' concerned it's abusing the engine for no gain.
Thank you for the fast reply.
1) That makes total sense. My motivation for this question came from experience with an ECU tune on my Miata. However in that case, the person doing the tuning had collected A/F ratio data from many previous Miatas running that specific aftermarket exhaust, and was able to tweak the tune accordingly. It makes sense why that doesn't apply here.
2) I guess this one comes down to a couple things...
I've been riding bikes with the Kawi 650 engine since 2010. Back then it was an ER-6n with an 11,000 RPM redline. Since then, Kawasaki has reduced it to 10,500 and then 10,000. I'm used to being able to ring this engine out a bit more than what the newer models allow. Power falls off after 9000, but there are still occasions where I want to run a gear out a little higher than 9500 rpm. Also, depending on the gearing, it might still put more torque to the ground above 9500 rpm than what it would upon shifting to the next gear. I did a little math to check this assumption.
Here's a comparison of a 1-2 shift at 10000 RPM vs 9500 RPM. I got my torque values from your dyno plot (here
). For the sake of this napkin calculation I assume drivetrain loss is constant and therefore can be excluded. My assumption was that due to the lower gear ratio, the bike would put down more torque to the rear wheel at 10,000 RPM in 1st gear than in 2nd gear immediately after the shift. The math below shows that assumption was incorrect.
1st gear torque @ 10000 RPM: 30 lb-ft * 2.438 * 3.067 = 224.3 lb-ft
1337.3 wheel RPM shift to 2nd results in starting 2nd at 7030 RPM
2nd gear torque @ ~7030 RPM: 44 lb-ft * 1.714 * 3.067 = 231.3 lb-ft
However, then I checked shifting at 9500 RPM. In this case, 1st gear was putting more torque to the rear wheel than 2nd gear immediately after the shift. So it appears that there is more meat left on the bone after 9500 RPM.
1st gear torque @ 9500 RPM: 34 lb-ft * 2.438 * 3.067 = 254.2 lb-ft
1270.5 wheel RPM shift to 2nd results in starting 2nd at 6679 RPM
2nd gear torque @ ~6679 RPM: 43 lb-ft * 1.714 * 3.067 = 226.0 lb-ft
The inflection point where diminishing returns kick in is just past 9700 RPM, where 1st gear wheel torque dips below the torque available by shifting into 2nd gear.
1st gear torque @ 9700 RPM: 32 lb-ft * 2.438 * 3.067 = 239.3 lb-ft
1297.3 wheel RPM shift to 2nd results in starting 2nd at 6819 RPM
2nd gear torque @ ~6819 RPM: 44 lb-ft * 1.714 * 3.067 = 231.3 lb-ft
In the grand scheme that 200-300 RPM extra isn't much, but it also isn't useless. In the rare event that you want to squeeze every last bit of power available out of the Versys engine, it's nice to have it there. Also, having a wider available RPM range makes each gear a bit more flexible. It's an extra couple MPH before having to shift on a straight before braking, etc. This isn't a track bike where every millisecond counts, but occasionally I find a good road for some spirited riding and want to make the most of it.
Also, it will probably bother me if the redline indication on the tachometer doesn't match the actual redline.
All of the above is probably just some mental justification for the actual reason right here.
I'll contact you via the email listed on your site to purchase.