2013 EC250 ?powervavle? problems

[rubber Jonny]

Hi all,

Got a problem with my 2013 EC250, bikes done 90 hours still all original piston etc. Was running perfectly well and all of a sudden its lost a load of top end power. I know you cant but if you could "turn the power valve off" its like that. Its not gone away over time just all of a sudden lost power as if the main jet was blocked or powervale not working properly.

Done all the usual stuff, carb cleaned, air filter cleaned, new plug, still the same.

I had some new exhaust packing I had not got around to fitting so I changed the packing make sure its not blocked, went for a ride, still the same.

Cleaned the carb again, was perfect as expected the bike has not been off road since the last clean. Took the covers off each side of the power valve to see what it looked like in there, bit oily but not gummed up, power valve moves freely. while i was doing this I looked up hole at the piston, its fine. went for a ride, still the same.

Now this is where I am, cleaned the carb three times. new air filter. new exhaust packing. inspected powervalve operation. took front pipe off looked up hole, piston looks ok. Im struggling with this now as I cant think what else to check without taking the top end off the engine looking at the piston and power valve assembly properly, dont want to do that unless I have to.

Any suggestions please?

[Caravan Monster]

Cleaning the powervalve isn't too bad. Possible to do without removing the barrel if memory serves and I expect there will be a good 'how to' somewhere on this site. I found semi synthetic tends to gum up a lot quicker than fully synthetic 2 stroke oil.

Reeds ?

Must be about due new piston rings at 90 hrs.

Does it tick over properly ?

[Wimpy525]

Just had this same problem with my 13. Checked what you mentioned above and found nothing. Figured it was electrical I was able to borrow a new stator and ignition. I plugged the borrowed ignition in and problem went away. So before buying the ignition I though the old one back in and the problem was fone. I figure it was just a bad connection. I ran the bike around my test loop for about a 1/2 hour and did not have the problem again

[rubber Jonny]

The bike starts, ticks over and runs perfectly until the higher RPM. You could ride round all day below half throttle / rpm and you wouldnt know there was a problem, its does not drink extra fuel, smoke or anything like that.

I have had the reeds out too, sorry forgot to mention that. They are perfect, like new.

I was thinking of doing the piston at about 150 hours. Could do it early but I doubt this is the problem so better to fix it before adding more unknowns into the mix. I ran to 150 hours per piston on my ktm 300 and expcted to do the same on the gas gas. My friend ran 253 hours on the original piston on his 2012 ec300 and it was ok when removed, slightly high ring gap but not bad at all, i wont be ushing it that far though!

Since my previous post ive found a "power valve how to" for the set up, I will do this next and see what happens. Lots of good info on that thread. Thanks to everyone who posted the pics and info. If that does not solve the problem I will try the electrical trick, above.

Cheers. RJ.

[Wimpy525]

Mine ran the exact same way. When the problem started I rode for a good bit under half throttle but anything above it would fall flat on its face. I'd unplug and replug the ignition easy enough to do

[djroggen]

Have you popped the pv cover off that's under the pipe off? That nut can fall off. Try that before any deeper tear down.

Sorry I missed that part earlier in your post.

Maybe try new main jet just in case it's plugged and you can't see it.

[rubber Jonny]

So I've tried all the above, powervale adjusted properly no probs there, checked wiring and unplugged cdi was very clean in there. Tried new plug cap, no change. Had a mate come round he gave the bike a good going over couldn't see a fault either.

Really stuck now, will try another main jet but I'm sure its not that.

[Jakobi]

Looks like we're going outside of the box.

How did you test the function of the powervalve? Disconnect the arm from the plate and then cycle the plate while looking the in the exhaust and check that the flapper opens and closes. You can run the bike with the RHS powervalve cover off on the stand and visually see that it is going through its range of motion. In the pri drive side its possible for a ball in the governor to get displaced and this can also inhibit the action of the arm. Something else to check.

While at it check the pipe for any obstructions/dings (maybe hiding under a guard). Have you tried changing/disconnecting the map switch?

Do you have any more info on whats happening? Does it just stop revving as in how? Blubber up, or just run out of grunt like when you're trying to pull a gear too high?

Have you tried a new plug?

Inspected reeds? Not that I would imagine they would be repsonsible for a top end issue, but never the less worth a go.

90hrs is just about due for a 250. I let one run through to 110hrs and pulled the end gaps out at 0.9mm, where as the 300's I would still find end gaps around 0.5mm even at 85hrs. The 250 works harder and as such wears rings faster.

Have you put the bike on a compression tester at all? Checked stator side to see if you possibly have a main seal leaking thats only pulling air at higher rpm. Same applies for the other main. Have you dropped the oil to check the volume? Any chance some is getting pulled in and being burnt and causing a rich condition up top. What about clutch action? Not slipping in the higher rpm and giving a feeling of having no power.

[hamilton]

Jakobi is just full of good advice, he should have his own troubleshooting hotline. I would take a close look at the power valve actuation. One other simple check is there enough fuel flow to the carb? restricted inline filter,petcock or fuel cap/vent check valve.

[Jakobi]

Originally Posted by hamilton

Jakobi is just full of good advice, he should have his own troubleshooting hotline. I would take a close look at the power valve actuation. One other simple check is there enough fuel flow to the carb? restricted inline filter,petcock or fuel cap/vent check valve.

Cheers Hamilton! And yours is a ripper too! Wence ziptied his fuel breather to the damper mount on his 2012 and as such it had restricted the tanks ability to breath just enough that it caused issues when getting into it hard. Sometimes it can be the simplest thing!