EC 250 2008 sticking idle and rattle

[mrfreezer]

Hi guys, I have EC 250 2008 racing and I have kind of rattle when idling and sticking idle.

I set my mixture screw 1,5 turn out from fully closed and idle screw a lot in. Bike idles really fine no matter if cold or hot, but when I blip the throttle idle sticks higher and remains until I put gear and loose the clutch a bit or plug exhaust with my hand, than idle is back at normal speed. Can it be because air leak? I have sprayed chain lube on carb manifold and no change, so there is no leak, but maybe crankshaft seal??

Although I have rattle on idle that I think is normal for 2T but maybe not. I have very similar rattle on Husqvarna WR 125 which is after engine rebuild. Is it normal or not? Maybe rattle from reeds?


https://www.youtube.com/watch?v=AIytJVgRp44

[mrfreezer]

little update.. I have set needle from the highest port to second from the bottom... air screw just 1/4 turn from fully closed and idle screw fully in.

No it looks it runs fine, no sticking idle, but if I turn air screw just a half a turn out, idle sticks again. Just tested it on stand and the smoke from exhaust looks like it is running too rich.

Will test it tomorrow on ride.

[pscook]

The rattle is likely from a loose power valve linkage. There are a couple of threads with great explanations and photos somewhere on the site; I have them linked on the home computer. But, the rattle likely isn't terminal.

[mrfreezer]

So guys, I have changed pilot jet from 42 to 48... now I have air screw 1,5 turn out from fully closed, needle on second clip from bottom, idle screw almost fully in... with this setting idle is not sticking, but it idles really low... I can?t make it to idle faster... do you guys think there can be some air leak?? or damaged reeds??

[mrfreezer]

So I have checked power valve actuator... the plate was touching the stop screw, but it was moving really easy few milimetres, so I adjusted it by preloading actuator spring with feeler gauge. Now it rattles less. I have checked Vforce reeds too... I have one damaged really bad and I can see light through tips of reed petals.. Do you guys think it could be the reason for bad unstable idle?





I set idle quite low, than I go for a ride. powervalce is sticking a little so I pull throttle to free it, but than it idles high for half a minute than the idle goes to set rpm... than again even in neutral when I blip the throttle more, idle stay high and after few second it goes to desired rpm. Is it possible that power valve does not close fully (high idle) and after some time and vibrations from engine it closes (normal idle)

[SpirosZ1000]

I have the same problem with idle on my old EC 300 sold to a friend of mine but I still service it for him. The bike works fantastic with high fuel economy and pulls like an ox but the idle never stays in desired rpm.
My fault is that I trusted him saying that the reed valve is ok when I told him to check it. If by any chance you find solution by changing reed pedals I should give it a try because I have checked everything else from crank seals, power valve, exhaust, triple checked carburetor and nothing.

[mrfreezer]

So today I changed reeds. Nothing have changed. I still have sticking idle, no matter what I do with air screw or ilde screw on carb... I can get higher idle, but than it sticks even higher.

https://youtu.be/gEhgDkM5saA

If it is true, that sticking idle is caused by lean mixture, than I have some leak. Last solution for me is changing crankshaft seals. Can you guys help me how to find out which seal is leaking? I have little oil spooge so it is possible I have leak on right crankshaft seal. And although as I remember when I changed oil, the old oil was not clear but kind of "foamy".

[islandrules]

I just did my crank shaft seals. The one under the stator you will need a puller for.( reverse thread) and the one under the clutch basket ( also reverse thread)you will also want to replace the o ring on the crank shaft. Mine was letting the oil get in the bottom end through that o ring, had half a cup or so in there.
Bike runs so much crisper now. Like a 4 stroke with hit haha, I however didn't have a sticking idel situation, bike would just load up real quick and take a while to clean out especially when cold,or when you want it to get on the pipe was all blurby. It's also a 300 but mechanically they are virtually the same.Hope that helps you

[mrfreezer]

today I found out that I have small oil leak on front sprocket seal... and I saw some small bubbles from there when bike was idling.. so now it is almost 100% chance of bad right crank seal. oil to engine = spoof, air to engine = sticking idle, pressure to gearbox = leak and bubbles on sprocket seal and foamy oil. But will check left side too, if there is some oil residue

[dANbOT]

Originally Posted by mrfreezer

today I found out that I have small oil leak on front sprocket seal... and I saw some small bubbles from there when bike was idling.. so now it is almost 100% chance of bad right crank seal. oil to engine = spoof, air to engine = sticking idle, pressure to gearbox = leak and bubbles on sprocket seal and foamy oil. But will check left side too, if there is some oil residue

The transmission is vented to atmosphere, and should not be blowing any bubbles through your countershaft seal.
In my humble opinion, it's time to leak down test your engine and definitively find out if you have an air leak(s). I personally HATE throwing parts at a bike without KNOWING what the problem is.