NSR powervalves don't close

[nsrpaul]

hi guys

I just had a miserable time at the last race meet on my mc21

hard starting, no power, traced to a range of faults including a stuck ring and and dead battery

once these were sorted it appears the valves are still playing up and to be different they open but dont close

My normal means of setting is to unplug the tps, yurn it on and the valves cycle to open

This only happens now with the motor started and when moved to open they stay there regardless of revs etc

we have checked the tps which appears to be working and swaped the servo motor out with one from my 28 (so know to be good) but no change

Paul

[spanner spinner]

check the feed from the cdi or coil feed that the unit uses to work out what RPM the engine is doing, sounds like the power valve is going to start position on turn on but then is not recognising that the motor is running.

[imdying]

I don't know much about the PV system on an NSR, but I'm pretty sure they reverse the PV motor polarity to wind it backwards. I guess there' a couple of high power transistors inside the PGM doing the switching, and I guess it's possible you can burn one out but not the other. Try another PGM. If the PV has a position sensor (I expect it will, probably three wire, probably very similar to the TPS), move the PV wheel and double check that that feedback look is giving correct looking value (i.e. it'll probably give you something like 0.8-1v on closed and 4.2-4.6v on open, assuming a 5v sensor feed from the PGM (that is typical, but given the age could be an old style 12v, so check the (presumably) red wire feed to the PVPS.

If none of that seems correct, sing out and I'll have a dig through the manual and see if there are any test procedures. (power feed from 2 wires an position sensing on another 3 wires is typical for this sort of stuff, but Honda is, ya know, Honda...)

[nsrpaul]

i managed to find a test procedure for the servo and that was ok, tps tested ok as was the stator and pick ups

took the plunge and got a pgm from deet in oz and it sorted it

Reckon it sounds like I had the wrong steer on setting the valves, it was always

unplug tps
turn on
servo moves to open
set valves to open (stick finger in port to check)

turns out that its not "fully" open and that the servo may have been adjusted wrong

now lacking clarity on how to ensure valves reach full open though as the "setting" position is around 2/3rds open