Monday, November 28, 2005

Tuning 4) F4 1000; Idle, throttle, blipping issues

submitted by MikeT

If anyone is wondering about why their MV1000 revs differently/sluggish when put in gear, I suspect that MV have done this by retarding the ignition timing, and progressivly advancing it again, so all's back to std by about 3000 rpm. The "sluggish" part is activated by the neutral switch to make the bike tractable in the very low rpm's, don't forget all the jap multi cylinder 1000's have a twin throttle system were you open one set and the engine vacuum/ECU opens the second set, MV don't have the room to do that due to the compact nature of the airbox etc. You could try"cutting" the neutral light input to the ECU which may get rid of the sluggish under 3000rpm bit, I must admit if you take off with some "gusto" and it goes over 3000rpm whilst also slipping the clutch it does rear it's head up!.

The other "no blipping" stuff that happens on the 1000 your going to need to adjust to, a power commander helps but it's still there, the bike basically monitors how fast it's engine is slowing down and then starts the "EBS" system, this system supplies air and fuel to cylinder two which opposes the braking torque, BUT it also supplies fuel to cylinder three, which doesn't want any! to get around this the "EBS" control unit removes the 12v supply to number three injector ( injectors always have 12v on them, the ECU shorts them to ground to "fire" them, and this MV ECU grounds them in pairs (1&4 2&3) hence the need to remove the 12v from injector three to stop it flooding the cylinder)

I am pretty certain when decelerating the "EBS" works to around the 5000 rpm mark (maybe 4700rpm) it then shuts all fuel off to 3000 rpm while/if still decelerating where you may notice a slight "kick" as some fuel is re-introduced, the "no blipping" on downchanges only happens in this 3000-4700 rev band when correctly fuelled with a power commander, and maybe less than that 3500-4500? I'm not too sure.You can improve it by blipping slower within these points to give the injection time to revert back to "acceleration" mode. It's not a perfect system which is why the new Senna has a different ECU , it's different, not wrong, once you adjust to it the corner entry lack of engine braking is amazing when the bikes "on song" in the 7000ish rpm's, it does work pretty good when you use the bike hard, even sounds good! more like a three cylinder when on the over-run.
Regards, Mike


Post a Comment

Subscribe to Post Comments [Atom]

<< Home