ec 300 2005 won't rev high nor idle...

[pitar]

Carb seat checked, seems nice and round.
Needle is at highest clip (leanest).
Cracked open the silencer and nothing appeared to be broken or bent.
While I was at it a also checked that the power valve works.
The valve opened and closed nicely.
Set the plug gap to 0,8mm and checked for a good and solid spark.
Everything seems to be in perfect working order.
With the ignition cover off i also changed the timing to have a bit less pre-ignition.

Bike still runs like sh**, revs high but sounds like it's on full choke.
It's the same sound and feeling you get when you let a cold started 2 stroke idle to long on choke and try to rev it high when you drive off.
With a good running bike it would smoke and stutter a lot, but eventually ,after 50meters or so, would get it's powerband and rev through the gears.

With this bike it just doesn't get to that powerband stage.
If you ride the bike the power delivery is extremely linear.
No peaks, no powerband, like a turboless diesel engine.

Any more ideas ?

[Anders]

Did you check the ground connection of the ignition coil? I had a similar problem on my 06 200. I tried all kinds of jetting changes. Found that my son's 08 300 ignition stator made it run as it should. Bought an Electrex stator, but that didn't help. Bought a complete OEM stator and flywheel (could not buy only stator). That helped for a while, but before long it was back to running poorly. Removed the coil, filed down the frame tabs to bare metal, renewed both coil screws and snap-in nuts. Replaced the plug cap. After that, it has run just fine for a year.

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[Neil E.]

Originally Posted by hannesd

engine has even been split

There is one other thing you should check. Find out if the piston is in backwards. If the piston has printing or etching on the top you might see it looking through the plug hole with a borescope.

[Eric]

Just thinking out loud...
Does it have a black expansion chamber or a chrome one?
If its the black one it has a catalatic converter in it and the bike will run like crap.

[pitar]

Originally Posted by Eric

Just thinking out loud...
Does it have a black expansion chamber or a chrome one?
If its the black one it has a catalatic converter in it and the bike will run like crap.

it has a chromed expansion chamber.
next item on the list is to check the ignition coil grounds.
if that doesn't help i'll take the cylinder head off to have a look at the piston.

[pitar]

i removed the igntion coil, rubbed the grounds with sandpaper until bare metal and reinstalled everything with some copper grease between it.
Removed the seat, gas tank and spark plug. With a torch I was able to see the little arrow on the piston pointing towards the exhaust. So the piston is installed in the correct way.
While i was at it I did a compression test. I've got a reading of 11bar (160psi) which seems alright i guess.
I replaced the spark plug and went out for a ride.
After riding i took the spark plug out and it looked wet and black.

Probably worth noting that when the bike is warmed up you can drive it at WOT in every gear without it running poorly. By that i mean that it will rev high and won't hesitate or stutter on a constant high rpm, so it's driveable but far from normal. It still has absolutely no power. It's even impossible to pop a wheelie in 1st gear. The power delivery is the same as a mopped

Would it be possible to check the crank seals by spraying some brake cleaner fluid on them while the bike is running ?

[timlh]

I had a similar problem with my 01 XC300. It turned out that although the power valve was opening and closing when I checked it. It was actually working backwards. It was right after I did a total top and bottom end build. Make sure that the power valve is in the most CLOSED position when the bike isn't running. Also maybe someone else can chime in here I think if you manually open the power valve there is a chance you can drop the ball bearings out of the mechanizism that opens the valve as the RPM's increase.

Please Note I Edited my post I mistakenly made a HUGE error original read "Make sure that the power valve is fully open when the bike isn't running." I corrected the same it now reads correctly. "Make sure that the power valve is in the most position CLOSED when the bike isn't running".

Read Glens, Post below he has the best method for checking it.

My sincere apologies for posting an incorrect Post. I thought I re-read it before posting to make sure it was correct however I didn't do a Good job at all.

[Jakobi]

You can cycle the PV while installed. Just make sure that the actuator arm is disconnected. Pulling up on this may dislodge the ball bearings from the governor.

[pitar]

Originally Posted by timlh

I had a similar problem with my 01 XC300. It turned out that although the power valve was opening and closing when I checked it. It was actually working backwards. It was right after I did a total top and bottom end build. Make sure that the power valve is fully open when the bike isn't running. Also maybe someone else can chime in here I think if you manually open the power valve there is a chance you can drop the ball bearings out of the mechanizism that opens the valve as the RPM's increase.

Ok you might be on to something here.
The powervalve is completely closed when the bike is not running.
I'll check it ASAP !

[GMP]

Noo.. It should be completely CLOSED when not running. You checked manual function by moving it by hand(disconnected) correct? This only verifies nothing is binding or sticking up top. You need to run the bike to check the governer function. Leave the right side cover off and replace the pipe. Run the bike, the actuator should stay on or very close to the stop bolt at idle, and move through its range quickly as revs increase until hitting the fully open position. If not, there is a problem with the governer or linkage. First and easy check is make sure that the link rod does not contact the edge of the hole in the primary cover, jamming it.