Really sputters at high revs now

[motopsycho87]

Hi, I recently purchased a GasGas EC300 2006 from 'greenlane motorcycles', a dealer with whom I suggest you avoid like the plague due to many lies in the sales process and general bad customer relations.

The bike
Since purchase I have
Changed oil
New oiled air filter
Rejetted for best performance (40pilot, 180main), running 32:1 fuelil


The bike ran great, in which I decided to ride on the local motocross circuit, half way through the second lap, suddenly the bike refused to rev high;
https://www.youtube.com/watch?v=4e_H_ogPWx8 - video showing the bike running badly.

This problem is now constant, I have checked the following;

Spark plug, replaced - BR8ES
Ignition coil, HT lead and plug cap replaced
Stator coil replaced - Electrex
Carb has been cleaned
Reeds are in good condition
Power valve is operating correctly
Piston appears clean and ring are in tact
Engine has very good compression on the kick start
All earth points have been checked
All wiring has been checked and re-shielded

The bike starts first or second kick every time, idles very strongly, but will not rev past approximately 5000-6000rpm. The bike can be ridden and still pulls at full throttle below this rev range.

At this point all I can think is that I have a faulty CDI? I have tried running the bike with both 'maps', bypassing the switch etc, but to no avail. Is there any way to test the CDI or anyone I can send it to for testing? Or are there any other possibilities you think I should consider?

 

[bonkeye]

http://www.youtube.com/watch?v=4e_H_ogPWx8

GASGAS EC300 2006

Since I've had the bike it has had a bit of a top end burble, which eventually cleared out, but now I have this. What do you reckon it is? I have changed the secondary ignition coil, new plug, ht cap etc, the carb is clean and float is correct, the bike runs just as strong as ever (even at full throttle), but right after the power valve opens it coughs and sputters and never clears out, any ideas?

have you inspected the power valve? mine wouldnt rev out sort of like that the bolt had come out from the rocker plate ive also had the lug snap off that holds the rod from the bottom end

dont worry about the words ive got the pic from a site on cleaning the power valve

 

[motopsycho87]

Still clueless

 

[Coop]

Make sure you are 1000% the system is grounded properly. I recently dual sported my bike and it was running similarly to like you describe. I could not give it more than 1/2 throttle without it breaking up. I went back over my wiring with a fine tooth comb and found the bad ground. My bike rips again.

 

[gassergrant]

any way you can get hold of a cdi (ecu) to swap over for a test, that might be a easier way of testing it.
is the exhaust blocked in any way ie carbon, mud wedge down it.
long shot I had a connection on the cdi come off it ran like that. run over the loom and check its all connected up.

hope you get it sorted

 

[Coop]

Any luck yet?

 

[motopsycho87]

So far replaced

coil
stator coil
cdi (rm125, got same, so switched back for good measure)
piston (wossner)


Reeds appear fine, power valve is operating properly.

This says to me either carb or crank seals? I've had the carb apart and can't see anything obvious, it ran fine on this jetting before so I'm not changing it, all I can think is the crank seals? Can these be changed with the engine in situe?

 

[john r b]

Negative on the crank seals,engine will need to be removed.

 

[Jiikoo811]

Negative on the crank seals,engine will need to be removed.

Flywheel side crank seal can be replaced easily just open cover and pull flywheel off..

Sent from Razr MAXX

 

[motopsycho87]

manual says right hand is done from outside??

 

[KTMAndy]

So far replaced

coil
stator coil
cdi (rm125, got same, so switched back for good measure)
piston (wossner)

Random question. Which stator did you get and where did you get it from?

My bike has been having the same symptoms as yours. I thought it was the carb jetting. But after 4 hours of carb in carb out etc. My friend came over and suggested it wasn't the carb as it was back firing through the air box suggesting it would be an electrical fault.

5 mins later stator off and it was clear 1 coil was hanging loose off its spline 4 others where black and floating loose inside there wrap.

But I can't find a replacement stator other than the oem part at just under ?400 for a 2005 bike it's a bit rich.

 

[motopsycho87]

The cure was,

New HT coil and new CDI. Looks like the new HT I'd fitted was buggered from the get go!