Powervalve Problems

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knackeredMk1
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Powervalve Problems

Post by knackeredMk1 » 30 Oct 2009, 09:53

Scrubs did a sequence for diagnosing powervalve problems -

Seem as though the power valve problem seems to be a fairly popular
problem I thought It might be handy to devote a single thread to it
instead of having to search through endless posts for nuggets of
information.

I've tried to the best of my knowledge (which is limitied to say the least)
to put together a fault finding guide for bikes suffering with a powervalve issue.

this is by no means conclusive - so if anyone spots any errors (besides
my spelling ) or can think of a better or simpler way of testing
something or have anything to add that maybe helpful to someone
let me know and I'll edit the post.


First of all remove power valve cover on the left side of the bike and
determine if the power arm moves when you open the throttle at high revs..

If not take off the two cables from the power valve arm (remembering or
labeling which go's where) and see if you can move the PV arm by hand
if it is stubborn the power valve itself needs cleaning -- this can be
reached by removing the front header exhaust and cleaning through the
hole or removing the cylinder head.

If the arm moves freely -

It's time to check the servo motor on the other side of the bike

On mk2 and mk1 models the servo sits behind the carb attatched
to the top engine mounts

On mk3 and AR's its the black plastic box behind radiator.


Take off cover and release the 2 cables from the wheel pully
(remembering where they go) now you can check both cables
properly to see if there stuck or causing any problems.


If all is OK its time to check the servo motor -
Start up the bike and watch to see if the pully wheel turns when you open
the throttle if it doesent give the servo motor box a few
light taps with a spanner or something sufficient - no
need to bray it to peices just a few healthy taps.
if it happens to spring to life, My guesses are
the brushes in the servo motor have gone there for a new
servo motor could be required (see below) this could explain intermittency. However continue testing to make sure.

If a good old trusty tap has done sod all then

kill the engine and open up the servo motor case.
Before you do this It will be wise to take off the petrol tank so you can unplug
the servo motor unit - so you can take it completley off the bike.

when you have unplugged the unit set you multi meter to continuity
testing and start by putting a testing probe on each wire on the plug
in turn, then find the same colored wire inside the box (attacthed
to the motor or whatever) and place other testing probe on that end.
the meter should make a noise, if the wire has no breaks. test all
wires.

after testing wires we need to take the 2nd cover off to access the gearing cogs
When taking off the cover keep the bit where the metal wheel pully is facing down
so the cog gearing doesent fall out.

After carefully removing cover examine the cogs to see if there are any
missing teeth, missing steel shaft gearing rods, lack of grease etc..
if any of the gears are defective you are in luck and you have just found
the problem just order any appropriate cogs needed. from a model shop
such as http://www.greenweld.co.uk/acatalog/Sho ... re_58.html


If the gears appear fine the problem hunting continues!

Time to test the Servo motor.

Get yourself a 9volt square battery, 12v motorcycle battery
or something suitable to power the motor externally.
I used a cheap mains voltage adjustable power pack set to 3v.
On most of the adjustable models there is a 9volt square battery conection
that is a perfect size to reach the 2 contacts of the motor if you havent any
wire to hand.

Does the motor turn?
If not you can purchase a new motor(Mabuchi - RS-365SH) which will be a direct replacement for $1.99!
https://www.addison-electronique.com/ca ... anguage=en
if you struggle to source one of these motors in the UK as long as you
find one with the same dimensions as the original (shaft length/width etc)
and roughly the same evoltage you will be fine since it is controlled
by the potentiometer.

If the motor works then its time to test the potentiometer..
(the round metal thing next to the motor)

The Pot has 3 connection terminals
Take out your multi meter and set it to ohms
Place one test lead on far left prong and one on far right
The potentiometers are 5k but will probably have around a 12% tollerance -- So the
maximum reading will probably be 4.40 (4400)
if its less than 4k -- I would say it is faulty.

Remove one of the test leads and put it on the middle prong (still keeping
the other test lead on the terminal left or right of it) and Rotate the shaft
of the pot - this should vary the resistance of the pot.
The ohmmeter reading should indicate zero ohms at one end of the shaft
rotation and 4.4k(or whatever the maximum reading was you obtained in
the last test) at the other. It should also show a smooth change in
resistance as the shaft is turned.

Move the lead that is still connected to an 'end' terminal over to the other
end then Rotate the shaft again while looking for the same smooth
transition from zero to maximum.

If its not working you're in luck another cheap replacable part,
actually you will probably be able to get them significantly cheaper than
the one on the link I posted but you get the idea.
http://www.happcontrols.com/amusement/g ... 205373.htm



If it works fine.. Treat yourself to a cup of tea and have a breather.



Time to check the wiring:

Your petrol tank should still be off.. giving you accesss to most of the wiring loom.

Start by checking for obvious breaks, corroded contacts etc.. unlugging
and cleaning all the plugs one by one with a quick blast of electrical
contact cleaner spray or WD40. and replugging.

Some of the plugs can be a little bit tricky to unplug and can appear jammed
when infact its just that they need unclipping properly.
the clips dident appear in obvious places to me (but then again I'm stupid)
so if your having to pull apart with force stop and examine for the release
clip last thing you want to add to your worrys is ripping a plug off.

Check/clean kill switch plug.

All good?

Now its time to test your rectifier/regulator.

There is no way to do this conclusively and test on the component level as it's sealed.
But some things can be checked so Here goes:

There are a six diodes in the circuit, which should permit current to pass
by in one direction, but not in the other. Usually if it's defective these
diodes are fried, and turned into ordinary wires, permitting current flow
in both directions.

we can test three of them indavidually..

There are 2 plugs leading from the reg/rec unit

one plug with a green and red wire (out put - positive and neg)
and one plug with three yellow wires (inputs)

Set multi meter to diode test function
(the reading on display will be in volts now not ohms.)

Put the red testing lead on the red positive wire and black lead
on each of the three yellow wires in turn .

you should recieve a 0 reading for each test.

Now swap over the leads in the multimeter and repeat the test exactly
the same red lead on red positive wire and black on each of the 3 yellow
wires again.

You should recieve a reading of around 534 give or take for each of the yellow wires.
They should all give the same reading if the diodes are
functional.

Now plug back in the cable with the three wires leaving the plug with the
red and green wire unplugged.

start up the bike and let it idle.

Set the multimeter to AC volts
place red testing lead on red wire and black testing lead on green wire.
if any AC voltage shows (not pulsating DC - True AC) -- at least one of the diodes has blown.
meaning you have a defective Reg/Rec and quite possibly CDI unit too.

However...do not start breaking stuff and swearing just yet

Since it's only the powervalve side of the PGM unit that has blown,
It is possible to buy a seperate power valve controller for 109 euros
from this place http://www.ignitech.cz/english/aindex.htm

It will even allow you to tweak and map it to suit your taste which
in my opinion is better than using a standard one.

They also sell a programmable PGM box so you can have away
with the rev limiter etc... Mugen eat yer heart out

Happy Riding!

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knackeredMk1
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Powervalve Adjustment

Post by knackeredMk1 » 24 May 2010, 21:44

All the PV servos are the same across Mks. Originally all Mks had p. no. 31420KAE004 but this has been replaced with 31420KAE770.

PV servos will not work if you connect them with the engine running. You need to stop the engine before you connect them.

To set up power valve (Mk1, 2 & 3) -
Image

Additional from Skidmark for an AR -

Image

To be absolutely sure that your PV is set up exactly but a slightly more difficult way -

With the exhaust off feel for the point where the PV is fully open against the exhaust port then mark the position of the PV arm against the barrel somewhere under the PV cover.

When you have got the bike assembled check that the PV arm lines up with the mark when the bike is running (at a high enough speed that the PV should be fully open) and adjust if it doesn't. This will give you a much more accurate setup for full power than the manual.

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PV Cables

Post by knackeredMk1 » 15 Jan 2011, 21:27

There are no more PV cables for Mk1 and 2. You can still get Mk3 and AR though. These are longer but that shouldn't be a problem. Keep this in mind if your cables are getting a bit ropey. Otherwise there is always the kits where you can make up your own cables using new outers and cutting inners to match with solder/non-solder nipples. You have to use the old fittings with this method.

I'm told LT are looking into getting some made up but I wouldn't rely on this happening.

Sometimes the power valve gets stuck or won't go its full travel because of carbon build up. If this is not spotted quickly it can lead to breakage of teeth inside the PV servo or worse ECU/CDI failure due to current overload. This seems especially true for ARs. Worn or frayed cables can also be a problem with sticking PVs.

It seems prudent then to check for easy and full movement of the PV periodically. This can be done by popping the PV cables off the cylinder where they meet the PV and twisting the PV with your fingers. Some owners stick a socket on the end of the PV shaft and twist the PV each way; but this is not to be recommended and doesn't have the sensitivity to resistance the other method has.


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