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+--- Thread: 04 Fazer 600 Flat Spot (/showthread.php?tid=83970)
04 Fazer 600 Flat Spot - Wildwi11 - 15-03-26
Hi everyone
Just 2 days ago, I acquired a 2004 Fazer 600 fuel injected.
Now I am very happy with the bike, but there is a massive flat spot between 6k to 8k rpm.
Could someone please possibly point me in the right direction on where to start with this.
I went into the diagnostic mode yesterday and Cylinders 1&4, were both set at -25 and cylinders 2&3 were set at -8.
Could this be causing it ?
Kind Regards
Wildwi11
RE: 04 Fazer 600 Flat Spot - Grahamm - 15-03-26
In order to give better emissions test readings, Yamaha put a "hole" in the power curve around 4-6000 rpm and unfortunately it's built into the ECU fuelling map.
If you look at the graphs below, you can see the flat spot on the top one and the hole in the second one around that rev range.
fz6_power_curve_before_power_commander.jpg (Size: 18.93 KB / Downloads: 14)
fz6_torque_curve_before_power_commander.jpg (Size: 18.44 KB / Downloads: 14)
Personally I bought a Power Commander III which let me change the map to smooth out the delivery, but there are cheaper versions available too.
Also it can help reduce the "jerk" you get when rolling the throttle on again after a bend, because the ECU cuts the fuel flow when you roll off and there's a momentary "lag" before the power comes back in again.
Another good modification is to get the 4 degree ignition advancer which improves starting and low to mid revs response.
RE: 04 Fazer 600 Flat Spot - agricola - 16-03-26
I suppose it comes down to what you want to do with the bike. If its a commuter, then the expense of sorting it may not be a good investment, after all, blistering acceleration is not really required for a commuter. On the other hand, if you do wish to be forced to hang on for dear life, then a Power Commander, properly set up on a dyno, is your answer. Not cheap, but light years difference in performance. I had my S2 model done and never regretted it for an instant.
RE: 04 Fazer 600 Flat Spot - Wildwi11 - 17-03-26
(16-03-26, 04:07 PM)agricola Wrote: I suppose it comes down to what you want to do with the bike. If its a commuter, then the expense of sorting it may not be a good investment, after all, blistering acceleration is not really required for a commuter. On the other hand, if you do wish to be forced to hang on for dear life, then a Power Commander, properly set up on a dyno, is your answer. Not cheap, but light years difference in performance. I had my S2 model done and never regretted it for an instant.
Thank you for your reply. I think a power commander will be on my shopping list soon.
RE: 04 Fazer 600 Flat Spot - Grahamm - 17-03-26
Regarding my Power Commander III, I also bought the "Dual Map" switch which mounts on the left handlebar and lets me swap between the "standard" map that just smooths out the fuel flow across the rev range, and the "fun" map which gives a big boost to mid-range power, but does cost about 25% of my fuel economy!
There's now also the Power Commander FC which is simpler and cheaper, see https://dynojet.co.uk/collections/power-commander-fc