Bryan
Gold Level Site Supporter
I am posting this from an email from a friend who I gave my old 2000 to for his grandson. It needed work that I didn't have time to deal with.
To set up the issue: He had rebuilt the engine, had the cylinder nikasil redone. Bike was back together, running, but would not idle. Ran great above 1/8 throttle (on the main) but could not get the <1/8 throttle to dial in. I had the same issue, and never could solve it either. Since I have a 2007 with a smart carb on it, I had the 38 MM carb that was dialed in from it sitting on the shelf.
from his email:
"I got the original carb on the EC300 working even better than the one off your bike.
An internal air bleed passage was blocked by sealant when they semi-permanently assembled the upper carb body. I had to take out the non-serviceable Torx screws so I drilled out the blocking posts in the center so my tool would work on them. I got that back together with no leaks (checked with soapy and air pressure).
I took out the 38 pilot jet and went to a 35 like the one in your old carb. Yours has a 180 main but mine runs fine on a 174 and a little too rich on your carb with the 180.
Now my air screw and idle screw actually function. Float is set at 16mm same as your old one.
Bike is running very good now and idles!
Still 4 strokes a bit at light loads and small throttle openings in lower gears. Running a gear high at low speed gets rid of most of the 4 stroking. The 2000 EC300 is definitely a bike designed to be ridden aggressively!
Please let me know when you get your Smart Carb perfectly dialed in as I would like to see the difference between our bikes at that point."
Not sure how many have a carb they just could not get to dial in, that foul plugs all the time. But this is another area to look. Also, note, he put fresh reeds in when he rebuilt the motor to make sure he didn't have any issue there.
To set up the issue: He had rebuilt the engine, had the cylinder nikasil redone. Bike was back together, running, but would not idle. Ran great above 1/8 throttle (on the main) but could not get the <1/8 throttle to dial in. I had the same issue, and never could solve it either. Since I have a 2007 with a smart carb on it, I had the 38 MM carb that was dialed in from it sitting on the shelf.
from his email:
"I got the original carb on the EC300 working even better than the one off your bike.
An internal air bleed passage was blocked by sealant when they semi-permanently assembled the upper carb body. I had to take out the non-serviceable Torx screws so I drilled out the blocking posts in the center so my tool would work on them. I got that back together with no leaks (checked with soapy and air pressure). I took out the 38 pilot jet and went to a 35 like the one in your old carb. Yours has a 180 main but mine runs fine on a 174 and a little too rich on your carb with the 180.
Now my air screw and idle screw actually function. Float is set at 16mm same as your old one.
Bike is running very good now and idles!
Still 4 strokes a bit at light loads and small throttle openings in lower gears. Running a gear high at low speed gets rid of most of the 4 stroking. The 2000 EC300 is definitely a bike designed to be ridden aggressively! Please let me know when you get your Smart Carb perfectly dialed in as I would like to see the difference between our bikes at that point."
Not sure how many have a carb they just could not get to dial in, that foul plugs all the time. But this is another area to look. Also, note, he put fresh reeds in when he rebuilt the motor to make sure he didn't have any issue there.
