Thread: xl 800 pv problem
08-28-2014, 08:50 AM #1
xl 800 pv problem
on 2001 xl 800 power valves are not working making the engine to rev only 6000 rpms and 40 mph, and servo is not cycling after engine stopped like it should so I disconnected the 2 cables and felt the cylinder very easy to operate if like something was disconnected so I took exhaust and valve covers off and yes, the front valve was stuck down and the top pin across was gone, found it hanging in just on top of the shaft so I replaced the valve ( no damage at all anywhere in the cylinder), took both off and clean very well the exhaust ports, they now slide easy, installed all new seals and wave eater clips, everything is working nice and smooth now.
checked also the servo, it was not working so I had one from 1999 xl limited 1200 pv, same look, same cable length only difference is the color of the plug, black on mine, blue on the old one and mine work, when I energize it with a battery it cycle well ( power on red and ground on black and gray as service manual says)
put all back together , servo cycle well like it should after quick start / stop but does not open at high speed / rpms.
by the way I checked compressions before starting the job, 125 psi on both cylinders.
my question is : how is the powervalve servo energized? by the cdi I guess but how to check that?
thank's for the help
08-29-2014, 08:06 AM #2
so I opened the electric box, like new inside, no sign of corrosion, then I found the gray wire going to the servo, checked for continuity all the way from cdi to servo , all good, also good constant 12.5 volts at servo and good ground too.
now when I ground the gray wire from the cdi side, it cycle the servo very well just like after you shout the engine off as it should but never stay open.
my question is : how does the servo keep the valves open ? is it grounded ore something?
thanks for the help
08-29-2014, 08:42 AM #3
Edit: I don't have the system block in front of me but I'm pretty sure the servo low voltage wires are tied to the starter relay. Check the continuity on them. If you were reading a full 12+- volts previously at servo maybe it's moot point. I do know that the positive side of the relay has copper conductor plates that go bad and either won't conduct current or will lower the current to various parts... .
Let us know what you find out please.
Last edited by jim mcgreehan; 08-29-2014 at 11:04 AM.
08-30-2014, 09:20 AM #4
yes I did again, good ground in the ebox, like new inside, strong clic on starter relay.
What do you call copper conductor plate?
08-31-2014, 09:05 AM #5
09-01-2014, 10:31 AM #6
ok you are talking about starter relay, yes there is a copper plate to make electric contact between the 2 bolts like most relays but the servo motor for ypvs is not working like that , it is a rotating motor that pull and push 2 cables, not like a solenoid
Trying to get the same ski to swap parts next week and will let you know.
09-03-2014, 07:58 AM #7
....understood. But the point about the plates degrading is that I believe since the current always runs through that post/plate to other parts of the ski, then even though after the 'starting current' is over, it still may have an impact of not being 'clean current' when the ski is running (and since the servo leads are tied to it...). And results in either inconsistant contact/power, or reduced/power/voltage. Again, this is just a theory. (Some may argue after the starting procedure is done there is no impact.) Yes please let me/us know what you find out (to make the forum benificial).
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