I recently posted a question about the possibility of my power valve sticking. I have tried various jetting and have checked the movement of the power valve. I have good bottom end power and good mid to top, when it all works properly! as I said before bottom end power is consistant, It dosent seem to come on the pipe at WOT, at 3/4 throttle the power always come on and I can then roll the throttle fully open. Could it be the reeds? The plug gap? The problem is very anoying as the bike can be upredictable. The bike is 2002 ec 300 with fmf gnarly using 98ron fuel at 50:1 putoline mx5.
powervalve/top end problem still!
- Thread starter moff747
- Start date
I mean upredictable as somtimes it comes on the pipe and somtimes dosent. It does it mainly after a period of low revs or slow riding (no more than 1/4 throttle). Once the bike revs up cleanly and does come on the pipe (after playing with the throttle) it will go fine untill another period of loww revs.
MattR
Super Moderator
It sounds like it is getting too much fuel and starts to load up. Then, you have to wait until it cleans out as you get on the throttle. I have been facing a similar dilema on my bike.
It definitely won't hurt to pull the reed valve assembly out and inspect it's condition. I just ordered some reeds for mine, since I noticed them not sealing on the manifold. Also, on black carbon fiber reeds, you can hold them up to some light and see if you light is passing through the fiber mesh. A couple of my reeds had light passing through (looks like pin holes). Both of these would let more fuel enter the chamber and richen the mix.
It definitely won't hurt to pull the reed valve assembly out and inspect it's condition. I just ordered some reeds for mine, since I noticed them not sealing on the manifold. Also, on black carbon fiber reeds, you can hold them up to some light and see if you light is passing through the fiber mesh. A couple of my reeds had light passing through (looks like pin holes). Both of these would let more fuel enter the chamber and richen the mix.
GMP
Active member
Matt,
The light test is not a very good way. The thin CF will show light through brand new reeds. Also the reeds may not touch the cage on all sides, but they should be very close. The main thing is that they are not frayed or delaminating on the edges. Mine looked perfect @ 46 hrs.
The light test is not a very good way. The thin CF will show light through brand new reeds. Also the reeds may not touch the cage on all sides, but they should be very close. The main thing is that they are not frayed or delaminating on the edges. Mine looked perfect @ 46 hrs.
this sound so familiar... now that uve mentioned it, i am currently experiencing the same thing and i understand what u mean on the unpredictable part. if i were to ride 1/4 throttle for about 15 mins, and immediately have it wide open, i'll end up having a fouled plug. it is really that bad, to the extend that i cant use a B8EG or B8EGV or any iridium plugs during races cause it will only last the first few laps. it was frustrating at first but i somehow learnt to live with it. dunn get me wrong, but ive tried numerous jetting, changed the reeds a few times but its still the same. honestly i dunn think that the valve is sticking. i resent to the fact that maybe my bike is jus born this way and spent more time riding it with a spare plug on hand (of course!)..
i sure will appreciate any help u guys could provide or any part that i may overlooked.
i sure will appreciate any help u guys could provide or any part that i may overlooked.I have fitted my new reeds, the old reeds had seen better days and 1 was split.While I had the carb off I noticed 2 of the pipes coming from the carb were clogged with mud so I cleaned them out. The problem is now cured completely, the bike now runs superb from low revs all the way to the top! and is consistant with it. As it was sugested the damaged reeds must have been overfueling it at low rpm.Thanks people for all the help.
I apologize in advance for this long post...but I have spent nearly 3 solid moths trouble shooting this problem.
I have had this dilemma for awhile with my 2001 EC 250 and I think I have finally come close to figuring it out.
Let me first say that I bought this bike used and did not know the maintenance history. It ran like crap and fouled plugs from the moment I bought it. It would not come on the pipe and it smoked like crazy.
After I replaced reeds, checked the power valve, swapped CDIs, replaced the right side crank seal, rejetted with a LTR Kit (180 main, 42 pilot and clip in the middle position on an LTR needle), checked the float level multiple times, changed brands and heat index of plugs, repacked silencer...etc, nothing improved.
I went for a test ride the other day and noticed that as the bike started to run out of gas, it perked up and ran fantastic. The moment I switched to reserve and supplied fuel to the carb, it started to bog out and smoke again at 3/4 - WOT.
This means I needed to lean the bike by adjusting the main jet or reduce the fuel level somehow.
I did both...
Today, I replaced the needle valve assembly in the float bowl which controls fuel entry into the bowl and went from a 180 main to a 172. I am also 3.5 - 4 (way too many) turns out on the air screw. The problem is almost gone. I may try a smaller main to see if it improves.
The only thing I am concerned about now is that somebody in another posts mentioned a spring that surrounds the needle jet under the float tab... I do not have one of these in my carb.
I have had this dilemma for awhile with my 2001 EC 250 and I think I have finally come close to figuring it out.
Let me first say that I bought this bike used and did not know the maintenance history. It ran like crap and fouled plugs from the moment I bought it. It would not come on the pipe and it smoked like crazy.
After I replaced reeds, checked the power valve, swapped CDIs, replaced the right side crank seal, rejetted with a LTR Kit (180 main, 42 pilot and clip in the middle position on an LTR needle), checked the float level multiple times, changed brands and heat index of plugs, repacked silencer...etc, nothing improved.
I went for a test ride the other day and noticed that as the bike started to run out of gas, it perked up and ran fantastic. The moment I switched to reserve and supplied fuel to the carb, it started to bog out and smoke again at 3/4 - WOT.
This means I needed to lean the bike by adjusting the main jet or reduce the fuel level somehow.
I did both...
Today, I replaced the needle valve assembly in the float bowl which controls fuel entry into the bowl and went from a 180 main to a 172. I am also 3.5 - 4 (way too many) turns out on the air screw. The problem is almost gone. I may try a smaller main to see if it improves.
The only thing I am concerned about now is that somebody in another posts mentioned a spring that surrounds the needle jet under the float tab... I do not have one of these in my carb.
Loosenut
New member
Yes you carb does. The bendable tab on the float makes contact with the spring loaded plunger. It like a tiny shock to keep the float tab from bending while getting slammed around from riding through bumps and landing from jumps. You want to set you float height without depressing the plunger (tiny shock). Slap a 42 pilot in that bike with the 172. Try the LTR needle with the clip in the middle position as well as the #2 and #4 positions.
It is still possible that your carb is worn out. I know I have seen 2 gassers newer than yours that needed new carbs. However, you can have your carb fixed, tweaked and jetted by Ron and be done with all the BS. I plan on sending Ron a carb this summer. It should be interesting.
Mike
Thanks. Running a 42 right now.
What is Ron's address? How can a carb be worn out? I might look into him rebuilding my carb.
