Question of POWER....

[anteva2]

Hello everyone !! I recently changed the original CDI of my 2005 for my previous CDI, the one I had in my 2003 Vmax with which I had the accident, a Dynatek 3000.

As many of you know, the U49 JYA2WExxxx models from 96 onwards were depowered from 145 to 143 HP.

Could someone tell me what? Carb? CDI?

Looking for carburetor configuration I see that it is the same for all US49, only those prior to 96 offered more power.

I am attaching a photograph of the CDI of my 2005... it is not on board

Why did Yamaha decide this?

Greetings and thanks again

 

[MaxMidnight]

Sorry if I'm missing the point but are you trying to regain 2bhp which is less than a 1.4% difference and which I doubt anyone would notice?
I suspect these are nominal figures and individual bikes may well differ by more than that depending how the tolerances stack up.
If you are trying to maximise what you have your time and money will be better spent on ensuring everything is set within spec and then have a dyno sessionion to optimise the fueling for your bike.

 

[anteva2]

You're absolutely right, it's ridiculous, but my desire to know and learn is endless. In any case, the only difference appreciated with those models prior to 90 were the CDIs that went from being analog to digital. Those from 85 to 90 were and are great motorcycles. Thanks Mad, regards

 

[one2dmax]

85-89 are analog and swap between those years for all electrical parts
90-07 are digital and again swap between those years but not the earlier range.
SOME of the electrical like the starter motor and stator fit 85-07
Carbs fit all years 85-07

The power level didn't actually change. Just the method for reporting it. Some models did not get the Vboost and or even restrictors on the slides but those are easily fixed.

 

[Fire-medic]

Sean, the 'restrictors,'
Didn't the Japan carburetor slides have raised 'caps' on them to limit movement of the throttle slide? Ones that you can cut-off?

 

[MaxMidnight]

Sean, the 'restrictors,'
Didn't the Japan carburetor slides have raised 'caps' on them to limit movement of the throttle slide? Ones that you can cut-off?

Yes and there was also something linked to the speedo that restricted speed?