YPVS set up ?

[ghettostan]

the reason why i took it out is because i had to take the barrel off to renew the piston and rings.

iv ran in the new piston and rings, about 150miles maybe more.

but im not sure how to make sure if i have put the YPVS back right.

connected to two wires back on, but it doesnt seems to go anywhere near the red line anymore... where as before i could hit 7/8 rpm and change gear but now i have to change gears at like 6rpm. the engine starts to scream at around 5.5rpm

have i connected the wires wrong. ?

the wires are labeled 1 and 2. not sure which one i need to adjust to make it rev higher. iv tryed both ways but not sure how much to adjust it by.

also top speed im getting is 40 to 45mph max. i know for a fact my bike could double that. well it ses so on the speedometre lol and i got 75 out of her before.

[twotakt]

It could be for a number of reasons, one of which could be the cabling between the servo and the powervalve. This recently happened to me after my top end rebuild, bike wasn't revving high and not able to get in the powerband. But after setting up the powervalve servo and cables the bike is back to normal again.

When you turn the ignition key on can you hear the powervalve servo operating? Should be a kind of 'whirring' noise.

Also take off the rubber cover off of the servo and check that the wires are connected up correctly to the wheel of the servo (you may have to remove the tank to gain access to it).

If you're unsure on how it should be set up just take a photo then I'll be able to explain it to you. However once its off it should be pretty self explanatory.

Also take the cover off the powervalve (should be two allen bolts); you should see a black piece of plastic which the cable from the servo runs along. There should be a notch in the black plastic piece which lines up with a 'hole' when the the bike is at rest, see the diagram below. If its not then loosen off the locknuts then adjust the cables to slacken off the cables and move the plastic piece (by hand) so that it lines up the notch and the hole. Then put an allen key (or something similar) in the notch and the hole to hold it in place. Then tighten up the cables to take up the slack and tighten the lock nuts.

If its set up correctly then when you turn on the ignition then the plastic piece should move clockwise and return to line up the notch and the hole. Also when you rev the bike hard then you should see the plastic piece moving clockwise (this is the servo moving the powervalve to open the exhaust port to allow the bike to rev out a.k.a. 'hitting the powerband').

Hope this helps,
Jack

https://aycu28.webshots.com/image/44547/2003077888716770679_rs.jpg
____________________
R.I.P. Tareree Shiimi, 1985-2008

[ghettostan]

[twotakt]

the valve shouldn't be moving anti clockwise, that suggests that the cabling between the servo and the valve is wired up the wrong way. If you could take a photo of your set up then I'll be able to explain it to you more easily than just in text. When you do take the photo make sure you take the black rubber cover off of the servo so I can see the silver servo wheel.

Cheers,
Jack
____________________
R.I.P. Tareree Shiimi, 1985-2008

[ghettostan]

this is how i setted it up for some reason
https://i30.tinypic.com/23jpkdy.jpg
when i turn the ignition on, the notch turns clockways then anti clockways. and when the notch meets the hole that means that it is fully open right? when i kick it over the notch comes back down which means it closes it. then when i rev it the notch comes up a tiny bit but never meets the hole.
https://www.youtube.com/watch?v=2NJgRGEN7xQ

but when i swap around the wires E.G. 1 goes into slot 1 and 2 goes into slot 2, it doesnt look nor operate right... when i rev it it shuts the gap even more...
https://www.youtube.com/watch?v=7tNsNW3Boww

iv put the wires back like on the first vid becuase that seems to work fine, but cant seems to hit the bands.

have i done it right?
only problem im having is the RPM it wont rev anyhigher then 6rpm. if i rev any higher im pretty sure the engine will blow up.

[twotakt]

The first set up is definately right, don't worry if the notch doesn't line back up with the hole once you've revved the bike as the same happens with my bike. From the first video everything seems to operating how it ought to.

When you do rev the bike hard, does the black plastic bit move clockwise?

As for not being able to rev higher than 6k I'm puzzled. Unfortunately this is where the extent of my knowledge ends, at this point I can only suggest what I may think could be the issues.

Servo itself may need replacing

Piston and rings are simply not worn in yet, as you clock up the mileage then the bike should perform better (my bike struggled to rev highly for the first ~200miles). Is the bike running better now than when you first installed the new piston kit?

Could be an issue with the powervalve itself (clogged up and unable to move).

Could be reduced fuel flow i.e. blocked jet and/or fuel line
____________________
R.I.P. Tareree Shiimi, 1985-2008

[ghettostan]

[twotakt]

Yea sorry I couldn't be anymore help, but I do know for a fact that when you rev the bike hard that the black wheel should move clockwise, in a similar motion to whats happening when you switch on your ignition (albeit happening much quicker).

It may be due to excess slack in cable 1, and too much tension in cable 2. Try to adjust each cable so that they have equal tension, but not too tight.

Hope this helps,
Jack
____________________
R.I.P. Tareree Shiimi, 1985-2008

[Philious]

Just a quick one to the DT owners on here, I've just bought a J reg 1991 I believe DT 125 R and I'm wondering what oil to stick in the gear box.

Any help appreciated
____________________
Previously; Honda XR125 - Yamaha DT125r - Aprilia Rs125 - Suzuki GS500e, Currently; Kawasaki ZX6R + ZX10R
Theory : Passed 28/7/09 Module 1: Passed 21/09/09 Module 2: Passed 23/09/09

[ghettostan]

ok jack thanks for trying.

as for the oil my manual says SAE 10w-30 for a dt125r 1998 ?

[Philious]

Nice one, I shall be sorting that this evening...

Many Thanks



____________________
Previously; Honda XR125 - Yamaha DT125r - Aprilia Rs125 - Suzuki GS500e, Currently; Kawasaki ZX6R + ZX10R
Theory : Passed 28/7/09 Module 1: Passed 21/09/09 Module 2: Passed 23/09/09

[dave-bowk]

The valve could be in 180 degrees out. take the cable drive disc off, turn the valve 180 degrees and try it then, wont damage owt if its wrong, just wont rev