powervalve cable stretch

[XRX1]

I finally cleaned my powervalves and had one sticking , who knows for how long?Can the cable operating that valve go bad/ stretch out ? Do I need to replace it?

 

[77-SRX]

When doing this maintenance you also need to check the end of the power valve that the cable end or barrel slides into. They have a tendancy to spread open at the end and the cable can pull thru. Also when cleaning the valves make sure you clean the carbon build up behind the valve that may prevent it from opening fully. After you have cleaned and inspected them you will need to adjust all three cables at the servo motor end. Your old cables should be fine but will need this adjustment.

 

[XRX1]

How do you adjust them?

 

[77-SRX]

Go to the tech section from the home page and you will find the procedure. I calls for the yamaha power valve tester to be used to get the valves in the full open position so the proper clearance can be set. If you dont have this tester you can run your sled at idle and force it drop below 900rpm by either turning out the idle screw and or flooding it with the choke. When the rpm drops below 900rpm you will hear a distinctly different sound from the exhaust (loud hollow sound) as the valves go wide open. At this point just hit the kill switch and you can go ahead and set the clearance. It's really very easy. If you had a stuck valve you will notice a big difference in performance........