High speed bump performance change?
 

Hi 2t gurus, I need some help. I have a new to me EC300 08.

The fellow I bought the bike off of told me the float needle jet was leaking. I fixed that by just cleaning it out. Checked the float level and it was at 16mm. I got that measurment from the carb site. Then on my second ride I was going down a trail in 4th or5th gear at a good clip but not on the pipe, say mid rpm range. Then when I hit a 3" to 6" rock or root the exhaust note would change to pap pap pap... and I would lose half of my power. So I backed out of the throttle, shifted down, then rolled on the throttle until I hit the pipe and it seemed to correct its self. Doesn't do it every time, but anytime is to often.

The only things I can think of are: Carb, exhaust valve/power valve ( are these the same thing?) or reed valve?

I hope some one can help!

Len.

My '07 300 does the same thing. It feels and sounds like a 125 when it happens. I'm pretty sure it's the power valve. I bought mine used, and after it did this the first time, I took the power valve apart, and cleaned a bunch of carbon off it. This helped for awhile, but it's progressively coming back. I meant to talk to the gofasters guys at a couple nationals, but never made it. I've also not had time to research further on this board. I'm running bel-ray H1R at 50:1, if it matters.

I am going to do the same. There is a thread that sounds like the same condition on this site. I have decided to do all the things one should do when you buy a used bike. I have started with the muffler, which the guy said was due for a repack. And boy it sure does. Doing my second over night soke with easy off overn cleaner to losen all the carbon up. I will then have a look at the power valve. My father inlaw is a rider and a master mechanic and he said to make sure all my carb vent hoses are cleared as well, and go over the carb completely. I'm running MotorX 100% synthetic at 50:1. The previous owner ran something else at 60:1. I talked to the dealer, and he said that with the synthetics you can run it at that ratio which is 1% instead of 2%. But he said I should stick to the 50:1. I will let you know if I make any progress.

It's usually not the oil ratio or brand that causes spooge, your jetting needs to be correct.

Spooge/ oil mix
 

One small note here. Don't get yourself confused with the oil percentages(1%, 2%, etc.) 1% is 100:1, way too lean on the oil and your jetting will be too rich. I would guess carb vent hoses for the problem you described. Let us know what you find. Jim

I believe I have solved the problem! I started with the PV. It was completely encrusted in carbon. I must have spent 2 hours just cleaning it. When I opened up the right side the actuator arm would stick 2 thirds of the way to the top every time I moved it up and down. Once clean and back together it moved nice and smoothly. Went for a ride today the bike ran perfect. I did not touch the carb because I wanted to know what fixed it. The PV didn't do it, then I would have went on to the next item on the list. I guess with a 2t that will be one of my routine maintenance jobs.

Thank you all for your help, much appreciated.

Len.

What did you use to clean the power valve?

For the most part I used brake clean, dental pick, and a wire wheel in my drill in the places and parts I could, not to much preasure. All the parts appear to be a hardened steel like a valve, so no marks or scratches were left on the parts. The bearings I sprayed with the break clean and wiped off right away. The bearings seemed to be in decent shape. I took the # off them, as well as measured them and will check with the local bearing dealer to see if I can get them cheap. When using the dental tool I was carefull to scrape with the side of the pick and not the direct point.

Hope this answers your quest.

Len.

One thing I forgot to mention. I could not get the piece inside the exhaust port out. (spiggot) I think it was called. It appeared to be free of carbon when I looked at it with the trouble light, and it moved freely. I did not want to force it. In the instruction it sounded like it should almost fall out.

Any ideas for that.

Len.

Not sure, all I can report is that mine is the same, loose and also free of carbon.

Thanks for your help!