ec 300 cylinder problem...

[knutte112]

Hi.

First post for me, please excuse my bad english.

I bought a ec 300 2010 couple months ago.

When i bought the bike it was running rich, or i thought so.

The bike have realy strong bottom but the midrange is crap.

After 100 hours troble shooting i found that the axhaust valves do stick.

Moves just fine in neutral, starts to open at 4500-5000 rpm, and fully open at 8000rpm.

But in any gear, and under heavy load, the exhaust valve does not move until 7500rpm.
And at that point they opens all the way.

Have tryed with another set of valves, but no differens.

I have meassured the bore for the valves in the Cylinder, and they are little bigger then my friends bore. But not much.

The bike have only 25 hours running, almost brand new...

Anyone heard of faulty cylinder?

gasgas known for cracks in cylinder?

Thanks

Johan
Sweden

 

[john r b]

Are you sure carbon deposits aren't the issue?

 

[knutte112]

Thanks for your answer.

Yes, i have cleaned my valves, but there was not much to clean, as the bike are close to new.

The other valves i tryed were full of carbon deposit. Tryed them as they were, and cleaned them. No difference.

New bearings, no difference.

Another governor, no difference.

Actually i have ordered a new cylinder/piston kit.
If the bike turns out to be good with new barrel, it will be worth the money. Otherwise, yeah, well i will know the barrel was fine.

Then i can make it a 600cc

 

[Zman]

I had a similar situation once with delayed PV actuation and found that the belcrank was somehow binding. I loosened the screws and reassembled and the problem went away. I know that is not a definitive answer but it solved my problem. Have you checked to see that the assembly works freely without the governor in place? Check that the actuator rod does not bind where it goes through the hole between the case and cylinder. Check for rod contact with the gasket too.

 

[knutte112]

I have not checked the assambly without the governor. Will do that.

But as far as i can see it really lookes like the rod pushes up when driving under load.

The connection between the actuator plate (on the right side power valve) is not super tight.
The pin are little smaller then the loop of the rod. I find the freeplay just normal, when i compared with other gg bikes. But the freeplay are big enough to see that the rod are pushing up when the rpm rises. The valves are still closed...

If i polish the valves to mirror finish and take the bike for a 10 minutes run, take out the right side valve i can see some scratches on it. Not deep, but i believe that is my problem.

Strange thing is that i cant see anything wrong when looking at the cylinder.
Just as i said, the slot were the right side valve are pushed in are couple of hundreds of a mm bigger than in other bikes.

 

[Jakobi]

With the PV assembled in the cylinder and the retaining bolts out, do the drums and flapper rotate freely 360 degrees in both direction (and change direction freely). You should be able to drive it from the flapper with little to no resistance. If it hooks up some, see below.

There are a few areas in the cylinder where the casting comes up to a point where the PV drums sit and seal. I've had them bind a little here in the past (due to carbon buildup on the drums). May be worth while just shaving these down a touch.

If its not that, I'd be looking more into the governor/bellcrank. How many shims?

 

[knutte112]

Thank you all for respons!

feels great that i finaly talk to people that can help me.

The valves are rotating freely.

Bellcrank, what part is that?

governor, hmm, can not understand how that part could be woorking just fine in neutral but not in gear... well, will check the governor one last time.

I dont have any shim at all. Tryed with different shims, but to no good.

 

[Zman]

The blue circle is what I called the bellcrank. If you remove the governor, you can then actuate the bellcrank to make sure the rest of the assembly moves freely throughout its stroke. The yellow circle is the area where the actuator rod can rub on the bore of the hole and gasket.