How to un peg YPVS power Valve.....

[Stuster]

Hi all,

done a few posts with regards to my DT 125 Lc (87) and have one last thing in need to now, (well for now anyway)

When the bike is at low revs it is very groggy and was told that this may be due to the PV bein pegged open. Now when the bike hits over 6000 rpm it is fine and sweet as a nut. I would just prefer the bike to run nice and smooth at bottom and top end.

Thanks in advance people
____________________
Yamaha TZR125 x 3 Lifan LF125 14-F x 3 Jinlun 125 x 1 Honda CBR 600 F1 Honda Varadero 125cc I am now starting my Honda VFR400 NC30 Project (Still ongoing 27/02/18) Daelim Roadwin 125R

[Vincent]

Does the bike have a Servo and pulley for the powervalves?
They will look like one of the two objects on the left of this pic, the round part with the cables coming out is the pulley and housing and should be attatched to the side of the cylinder:-

https://i77.photobucket.com/albums/j71/Drewskovitch/P1010347.jpg

You will also need a PV control box, the object on the far right.

Once you have all these, all you need to do is connect them up and free off the powervalve itself which is more than likely coked up and seized.

You may also need to replace the seals and possibly the bushes on the powervalve too.

It is well worth doing, I tried my 350 with the PV stuck open and it was terrible around town.

[Stuster]

[Vincent]

wel personaly, the only thing I have garages do is remove tyres. If you trust the garage, you could get them to have a look to see what's wrong but, apart from the electronics in the PV box, it's actualy quite easy to work on.

First step might be to check all connections, then remove the cables from the pulley and see if the servo is performing its "cleaning cycle" on start up. If the powervalve has seized it can stop this happening.

[27cows]

Powervalves were normally pegged open on restricted bikes that didn't have an active servo (it used to cost £200 to get the bike derestricted, and you had to show a full licence to boot, back in the good old days).

Up side of a pegged open PV is that you got quite a bit more power than when restricted. Downside it that the PV doesn't give the even power through the rev range as it obviously can't open gradually as the revs rise, so it's on/off with a narrow powerband and bugger all power for low speed pottering.
____________________
The RXS100: vehicle of choice for Chuck Norris

[ms51ves3]