Will not reach powerband 06`EC300

[stian]

I am near selling the bike. Tired of this spanish crap.

Ec300, 2006.

Carburator

AS1, 178 main, 40, 7 slide, 1,5turns out, N1EG, 2 clip from top. Have tried 180, 182 mains, 40,42,45 pilots, N1EF needle.
I have also tried changing the carburator to AS2, with 180 main, 42 pilot, 7 slide, N1EF needle, 2 groove from top.
500m over sea, 12celcius.

Reeds: 2/4 blades are new, everything is OK and in good shape.

Piston: Rings and piston are well within specs. Under 25h on piston.

Head: Shaved 1mm, this problem was also before shaving the head.

BaseGaskets: 2x0,5mm. Squish is 1,6mm +-0,2mm.

Sparkplug: New BR9EG, tried swapping with another one also.

CDI: Standard one, but tried a KTM Cdi with no changes.

Coil: Standard, tried a KTM, no changes.

All gaskets are new, new oil (GRO), new petrol (95 RON, 2% GRO oil).
New rear silencer, front is std. GasGas.

Powervalve: New bellcrank, polished powervalve parts, new bearings. Rotates easy, and I have checked that governator balls are in place.

Every seal, and every bearing is new in the engine.
New voltage regulator.
New stator last year. iginition timing is locked in position with the bracket.

I am out of ideas. Starts easy, but will not reach powerband. Powervalve is easy, so I would guess that its electrical fault, men CDI and Coil has been changed with parts I do know work fine.

Tips?

 

[(F5)]

So you skimmed the head, but didn't open the chamber? 1mm will be 4cc so if I'd done that to mine I would have had 14.8:1 compression ratio. Which is a mighty high compression ratio for a 300.

Has it ever run well?

Maybe you've fixed the first issue and clouded it with too much comm?. Perhaps your local gas needs a smaller main as well.

 

[barossi73]

Do you have good fuel flow from tank?
Partially blocked fuel tap or inline filter could run ok idle/slow but starve engine of fuel at higher rpm.no tight bends in fuel line?tank breather clear?restricted fuel line?
(Restricted fuel flow is the only thing i can think of that you didnt mention)

 

[Zman]

Do you have good fuel flow from tank?
Partially blocked fuel tap or inline filter could run ok idle/slow but starve engine of fuel at higher rpm.no tight bends in fuel line?tank breather clear?restricted fuel line?
(Restricted fuel flow is the only thing i can think of that you didnt mention)

Excellent point! Some filters drop fuel flow. Also make sure your floats are set correctly and make sure the carb is actually level. GG bikes put the carb on two separate angles relative to the line of the bike and float height can be tricky. While they may look level, you should check by putting a small level on the carb top flat to verify. Often you will see that it needs to be tipped further back toward the gas tank.

 

[stian]

Carb is clean (second carb is also clean) and there is no fuel filter. Fuel is also free flowing.

The problem was there before cutting the head also. High compression or not.
95RON both times.

Can it be a electrical problem? Its an old bike. There isnt a mechanical problem as it seems.

How do I measure if the electric power is correct or not? Ive tried different working CDI`s and coils. Stator swapped last year.

 

[Zman]

Does it free rev into high rpms? Can you post a video? How does the plug look?

 

[motopsycho87]

Best bet is to post a video. ive had 3 stators on mine which has killed 2 cdis. Are you running a non-resistor spark plug cap, that can cause it. Check all cable connection and earths.

 

[stian]

Best bet is to post a video. ive had 3 stators on mine which has killed 2 cdis. Are you running a non-resistor spark plug cap, that can cause it. Check all cable connection and earths.

I am not new to two strokes. Best bet isnt a video,but rather measure all electrical sources. Ive tried other plugs and cdi 's and coils.

 

[Zman]

I guess you know best.

 

[GGRider01]

Does it just bog and die out with the throttle wide open? Or does it rev up fine but never have a "hit" when the valve opens?

My bike never had a hit until I started changing needles..

 

[motopsycho87]

Do you freque tly ride the bike through water? Or pressure was it. I've learned now after 2 stators to stand the bike bolt upright after washing and let it run for a bit to get any water to drain out.

Electrical problems tend to get worse at higher revs due to higher voltage allowing it to arc. A stator can read fine, but arc at high revs...

 

[stian]

Does it free rev into high rpms? Can you post a video? How does the plug look?

Was not my point being a "know it all", but uploading a video of a bike stutter at 5000rpm isnt giving other replies then "PV, carb, reeds, plug?"

Carbs,reeds are good, plugs are good. Needle has been replaced to different needles. powervalve bellcrank is new, powervalve has new bearings, as the hole engine, and the powervalve is turning freely. It wont open, but that could also be the bike not wanting to reeving out.

Ill have a look at it again. I have a KTM 250 exc, so I could swap the stators if they interchange also. Lights are still working, so the voltage reg. is working

 

[motopsycho87]

I really would say post a video. I've had no end of shit with 2 strokes, rebuilt many, and many wild goose chase (normally electric!).

Your jetting is spot on, with the gg, every time I've differed more than 2 jets off the average,its been masking some other problem. Make absolutely certain you have a resistor type spark plug cap and tte earths are correct on the ignition. Take the side cover off the power valve and male sure its opening. As long as you are certain the engine is sealed, and fuel is being delivered, it points to electrics. And like I said, I've killed 2 stators on mine in the past 2.5 years. The dry side does not seal well, and when they go they have a habit of killing the CDI too. And simple as it sounds, change the spark plug for iridium, "racing" 2 stroke seems to kill standard plugs of the same heat range for me, but I've had the same iridium for a year now with now problems.

Please post a video.

 

[GGRider01]

There is an important distinction that needs to be made here to help me wrap my head around it. If you go WOT it will rev up to about 5500 and then sputter? Or will it sputter right away if you pop the throttle wide open?

I ask because, first of all, this has to be something simple and silly that is getting overlooked. I once had an RM125 that suddenly wouldn't rev up, but I noticed it was directly related to throttle position. Popped the drainbolt off the carb and the main jet fell out.

Also, I recall a thread recently where a person was diagnosing bizarre ignition problems. Turned out the ignition coil bolts were corroded and weren't providing a reliable ground. When I was diagnosing my no spark situation, I stripped all the tubing off my harness and inspected every inch of every wire. So I definitely know the frustration you're dealing with.


Are all the balls still in your PV governor?

Definitely give that KTM stator a try. If it's the 2k2 stator and your bike has the 2k3, this will be problematic. You'll need to swap plates or modify the KTM plate anyway, if I recall. Easiest method would be to find a nearby GG owner or dealer (hah!) and try theirs.

 

[Jakobi]

Yeoop!

I'd be checking the PV governor and making sure the actuator arm can and does work as it should; not just checking that the drum valves and flapper 'can' turn.

Consider changing carbs if you have the option. The nozzle could be flogged out, but I imagine you'd notice it across the rev range rather than the behaviour/issues you're having. Regardless check off the list what you can!

How's the exhaust? Do you have anything that is seriously restricting flow and choking it? Rag in the pipe? Ratts nest? Packing fluffed up? Kids toys?

 

[Jakobi]

Haven't got a rag stuffed in the airbox/intake?

 

[barossi73]

Not having dismantled the pv flapper myself yet,but am wondering if it can be assembled 180deg out?
I cant remember if the actuator plate has 1 flat edge or 2 locking it in position,but if the pv assembly can be rotated thru 360(disconnected)and theres 2 flats,in theory it could be 180deg out?
Or perhaps it begins to open and actuator arm fouls,limiting travel?

 

[stian]

Ive had the governator up couple of days ago - all balls are correct located in the inner area. The PV flaps is also corrects, and opens as it should when turned.

I have swapped carbs. I have swapped mains, slide, pilot. Air-filter is clean.
Swapped out sparkplugs.

It did run fine 15min down the road, and then suddenly started to bug out as it has been doing since I had it. Its leaning against bad connection somewhere in the harness.

I have also swapped out CDI,Coil, and even the controlls on the handlebar.
Going to swap out the screws on the coil, and try a KTM stator, with the KTM flywheel (2k3).

Put my voltage meter on 2k ohm and testet my ignition coil with cap on, it gave 10,88. KTM coil gave 10.98 or something. I am guessing thats fine

Was out 00.00 yesterday, took a look at the wiring.
Wires from the CDI does not follow the wiring diagram found online.
Do anyone have a suggestion about these wire and their color?

 

[GGRider01]

Some people say these ignition coils shouldn't be returning thousands of ohms, but I stand by the fact that 2 of mine do and also work.

With the cap on, I measured 18.4k ohms from the cap to the white/bluestripe wire on my ignition coil. This was with it removed from the bike. I'd wager yours is too low, but it's odd that your KTM is pretty much the same.

 

[stian]

Some people say these ignition coils shouldn't be returning thousands of ohms, but I stand by the fact that 2 of mine do and also work.

With the cap on, I measured 18.4k ohms from the cap to the white/bluestripe wire on my ignition coil. This was with it removed from the bike. I'd wager yours is too low, but it's odd that your KTM is pretty much the same.

Well, kinda funny, cause my KTM also started to bug couple of days ago. But if both coils have gone, thats one bit of a coincident

I am kinda sick of this.
Correct settings on the voltage meter is 2k on "ohm"? Both showed around 10.85