newyamaha2me
New member
hi im going to adjust powervalves for first time but i have a couple questions.. first when i run sled and choke out to get rpm down under 900 i see wheel turn and open up valves with cables all the way slack the wheel still turns back just alittle as soon as i kill the sled.. where do i mark the wheel is it when the sled is running and wheel turns to open valves or after i kill the power and the wheel has turned back just alittle?? second question is do i have to remove the four bolts on the housing along with the two bolts, or just remove the two bolts??
super1c
Super Moderator
Not sure why its turning back on you when you kill the engine, did you use the kill switch? For adjusting only need to loosen the 2 bolts. the 4 bolts only need to be taken out for removing and cleaning of valves.
newyamaha2me said:
One or more of your cables are too tight to start with so when the servo runs up against a too tight cable it turns back slightly. Try loosening all three adjusters and reset the servo.
If they're too tight (as witnessed by the servo turning back) you may want check the PV shaft ends for a near pull through. This is the cause of pull throughs.
Secondly, just loosen the two allen head bolts (cap screws) that attach the cable end housing (at least 3-4 turns but don't remove them) and adjust the cables so you have 2.5mm clearance between cable end housing and the PV housing. The only time you'd remove the four PV housing cap screws is when removing the PV for cleaning.
Find a coat hanger that uses the larger diameter wire and you'll find it to be around 2.5mm. Bend it into a u shape and use it in place of two allen wrenches placing the two ends just inside of the cap screws. Tighten the cable adjuster until the housing just touches the coat hanger. Remove the coat hanger, tighten the two cap screws and move onto the next.