Hi

My Honda CBR 929rr year 2000 (sc44), has been in the workshop because the engine light was on.
I was told it was a mistake on the

has part number:
motor unit servo 31420 MCJ-640

The workshop's solution is to keep the unit open all the time (active), this turns off the engine light and the motorcycle can run.
I have read that if it is not mounted/active, there are approx. 8% less bottom draft - what is your opinion on having it assembly/active or not?

Could it damage the engine?

Is it a waste of time and money to find and replace?

I hope you can help with answers to my questions. The spare part costs a lot of money.

<< I'm from Denmark, sorry if there are spelling mistakes :-) >>

 

What was original problem? Servo flap wasn't moving properly? This is usually problem with lubricating cables between servo motor and flap.

Test each part by itself. Disconnect both cables from servo valve and motor:

1. does servo flap move easily by hand?
2. does both cables slide easily inside housing when "flossing" back & forth?

How did garage rig it to keep valve open fulltime?

Without servo flap working properly, yes engine has less low-end/midrange torque and bike is slower in street riding. Should only be done on race-bikes.

 

The fault was that the engine light was on. The reason it was lit was that the servo for the exhaust damper was not working.

By removing the wires, the throttle is now open all the time, like on a race bike.

I'm worried if it will damage the motor. There are many opinions for and against.

I can find a used part and replace it, but if it's not necessary, I'd like to save that money.

 

It won't hurt engine with servo-motor disconnected.
You'll just lose some low-end/mid-range torque.

 

Thanks.