Cup bike ECU reflash and throttle bump stop?

[noamkrief]

Hello, it's me again.
My dealer said he can't legally tell me how to do it but he said it's easy.
On the cup bike, to get max HP he said he can have his tech reflash the ECU, about 1hr labor, $125
But I would need to take apart the throttle assembly to remove the throttle stop so I can twist all the way.

1) when I take apart the throttle assembly, will it be easy to find? Anyone have some photos or instructions?
2) why does the ECU need reflash? to increase the rev limit?

Any information would be very helpful
Thanks
Noam

 

[cjwell]

All you have to do is take throttle stop off throttle body, no re-flash needed, it has the cup map in it... The stop is on throttle body not in housing on bars.

 

[noamkrief]

chad, thank you.
1) so why do you think the dealer say I need to re-flash?
2) so I have to take the tank off, then I will find the throttle stop? It would have been easy if it was on the bar part

 

[cjwell]

I have no idea why your dealer says it needs a reflash, probably misinformed or not aware of the differences. No need to take tank off to remove the throttle stop. Left hand side of throttle body open throttle and find the metal piece the hit it hits acting a the stop on top of cast aluminium body. One screw holding it on.

 

[streetfighter]

sorry for my ignorance, what does a throttle stop do? and what side effect it would have on the bike if it was removed ?


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[green_bread]

Its just a spare piece attached to the throttle body to keep the valve from opening all the way. What feels like 100% throttle is actually only like 95% throttle.. if that makes sense? You remove the extra piece and it allows the throttle body valve to open to 100%... thats it.Think of it like if you were driving in a car and someone put a block of wood under the accelerator pedal. You could mash the pedal down as far as possible, but its still not gonna give you 100% throttle until you move the block of wood out of there and can press the pedal ALL the way down.

 

[cjwell]

It limits throttle opening to 80% so 72ish degrees instead of 90.

 

[streetfighter]

so in order to open the remaining 18 degree of throttle opening with the throttle stop removed, i also need to twist the throttle on the handle bar a 20% more degree than before, correct ? if yes, a quick turn throttle should also be fitted in order to compensate the extra degree of twist needed by my right hand?


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[cjwell]

It's not a 1:1 to ratio, 20 degree at throttle plate isn't 20 at throttle tube. A quick turn throttle will make the pull shorter, but it's not a must. The cup has the rc8 throttle housing and tube on it. Just remove the stop and give it a "feel" before deciding on quick throttle...

 

[streetfighter]

Thanks for the clarification Chad. so extra throttle tube twist angle is needed in order to achieve the 90 degree opening. I was implying 20% more twist than before. frankly, the original throttle tube's travel is already pretty long even if the throttle stop not removed. I always need to reposition my wrist in order to pin the throttle handle. Now there is a better reason for me to get the quick turn throttle tube.


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[streetfighter]

is throttle stop screw shown on this diagram?


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[Tdel]

No it's behind the cam that the throttle cable mounts to. In this picture it would be on the right side and the ear that's on the top of the cable mount will hit the plate at about 2:00. It's held in place by a small 8mm bolt.

 

[Diploman]

Chad, is the throttle stop removal applicable to all 390's, not just the Cup bikes? Doesn't require a remap?

 

[cjwell]

Chad, is the throttle stop removal applicable to all 390's, not just the Cup bikes? Doesn't require a remap?

The throttle stop is only installed on the "cup" bikes, not the street RC or Duke 390. The akra map comes in the "cup" bike, same one I use on all my builds.

 

[CDN Duke]

The throttle stop is only installed on the "cup" bikes, not the street RC or Duke 390. The akra map comes in the "cup" bike, same one I use on all my builds.

Thanks for that detail - would have been my next question also. Just picked up my Duke, had akra map flashed before delivery