When to re-jet

[Calum]

@dtlee Depends what you mean by "turned the powervalve flush with the port".

The powervalve needs to be setup appropriately, not just abitrarily moved, unless pinned. To see if it's the PV I usually just pin the valve in the open position and disconnect the servo. If it's running sweet past 6K after then you know that you've messed the PV settings.

If not, then you know the problem lies elsewhere.

Is it jetting? Unlikely, the bikes default jetting is spot on.

[DTlee]

@calum cheers ill give that a try first, see if i can rule one thing out at a time. i want to mess with as little as possible as my mechanical knowledge is near nothing, although i di like to try and understand how it all works and learn for future.

[DTlee]

@calum what is the easiest way to temporarily pin the powervalve open to test this ?

[Calum]

@dtlee Take the exhaust off, turn the ignition on and the powervalve should automatically go to its most open position. If it's not, then you'll need to adjust the cables and switch the ignition on and off to reset the valve. Repeat until the valve is completely flush with the exhaust port. Then disconnect the connector block that powers the valve.

[SpookDog]

@dtlee

Don’t change the plug temp. Find out and fix the fault. Check your filter isn’t blocked. Black and wet indicates rich running, not burning all the mixture. Make sure the choke is closing properly. Rule out these then if not fixed check ignition...

[DTlee]

Thanks for the reply’s, I’ll pin open the powervalve and check that and while I’m there I’ll take the carb out and give it a clean as it’s not been taken off in the two years I’ve had it, the bike doesn’t get a great deal of use. It has a new air filter in it so that should eliminate that being a problem.

[markus.w]

@dtlee the bike doesn’t get a great deal of use? Maybe that's your problem as it can only take a few weeks for the fuel in the carb to gum up and cause a partial blockage and even more so if you premix. maybe you just need to give all the jets a good clean. If you know it won't be used for a while it's good practice to turn off fuel tap whilst still running and let it run out of fuel so the carb is empty.

[SpookDog]

@dtlee
Why pin it? Do you not have a power servo for the power valve?

Electrical misfire can cause a black wet plug as well...

[Calum]

@spookdog Pinning it open rules out the powervalve which is what I see 90% of the time being the problem. I suspect, by the way they've stated they've "changed" the valve settings that this is the cause.

[DTlee]

@markus-w good shout, i use it every couple of months so ill give that a try as well.