Exhaust valves adjustment for a two strokes

[centaurus]

I have reasons to suspect that my exhaust valves are not properly adjusted. I tried finding on the net some sort of procedure for checking and/or adjusting the exhaust valves cables, but I couldn't find anything.

Can anybody give me some information or point me in the right direction?

Thanks!

[Ixion]

Ask Mr Peanut he knows all about NSR250 power valves (seriously)

[Mr. Peanut]

Do they move when you flick the ignition on and off?

[centaurus]

If the engine has been off for some time, they move when I turn on the ignition key, but not when I turn it off.

When the engine runs, the motor that moves them keeps moving back and forth every few seconds, so I'm assuming the system is ok, but the valves cables are not properly configured.

[Mr. Peanut]

Are the power valves actually moving though? Adjustment is fairly straightforward.

Turn on the ignition key and turn the RUN/OFF switch to RUN. He valves will settle in the closed position.

Now turn the switch to OFF and unplug the TPS (throttle position sensor, the connector's white with three wires connected to it. It's beside an identical green connector, on the right hand side of the bike.). Turn the switch back to RUN and the valves will move to the setting position.

Looking from the R/H side of the bike you'll see that there's a hole in the actuating pulley of the valves, and another in the plate bolted to the cylinder. These holes must align. Loosen off the adjusting screws off the RC Valve cables and adjust as necessary.

There should be no tension in the cables, with about 1mm of side-to-side play. Repeat the above procedure until there is perfect alignment.

Hope that helps.

[centaurus]

Thanx MrPeanut. It worked.

I still have some issues on the other cylinder - doesn't seem to fire everytime and sometimes the explosion is quite weak, so I assume fuel mixture issue (I checked and it seems to have spark).

On Wednesday I take it for a WOF anyway, so and I'm gonna ask them to diagnose this problem too. I haven't played with a carburetter until now and I understand it's quite tricky, so I better leave it to to the professionals until I know what I'm doing

[Mr. Peanut]

Good to hear.

Re: weak firing -Tried replacing the spark plug yet??

[centaurus]

I switched the spark plugs between them and still the same: the top cylinder is running smooth and the bottom one si running rough and smoking: some explosions more powerful than others and some missed explosions.

Both plugs are about 2 weeks old anyway.