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I am going to need to rejet my carb, I have found the 15mm dellorto style carb for $34, would I be better off getting that and some jets or just getting the jets for the carb I have ported out. I am not sure flow difference between the 2.
 

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Them copy Dell carbs have no adj, other than the main jet. Better off with a $65 Walbro carb kit, with manifold to air filter.
 

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The Dell carb is a 14/14mm carb I have 3, one came on my 50cc C1. I have one on Sam's 40mm Cag Canted head engine, that's works preety good, might need a jet kit.
The Walbro 603 or Copy carb has a return line from the carb to your tank. I put a brake bleeding fitting in my gas cap and run it back there. look at my avatar bike photo.
 

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Walbro or Copy pumper carb. No turn off valve to leak, no float bowl or needles or jets, etc. Easy to adjust, one idle & 2 screws on the the side, High and Low speed jets.
 

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Hey EPR i see that you don't run a choke with the 603 carb. What is the reason for that? When i open up my choke all the way my bike boggs out could that be because i am running 91 octane fuel on it? Is 100 octane racing fuel a bad idea for one of there engines?
Thanks
 

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Hey EPR i see that you don't run a choke with the 603 carb. What is the reason for that? When i open up my choke all the way my bike boggs out could that be because i am running 91 octane fuel on it? Is 100 octane racing fuel a bad idea for one of there engines?
Thanks
You gotta learn how to tune..............The fastest and easiest way I learned was getting into nitro r/c from when I was younger til now...If you can tune-in an r/c nitro engine you can tune almost anything....



Walbro carburetors are almost standard on most all two-cycle engines. Adjustment of the carburetor may have to be performed on a periodic basis and most definitely after the simple device is rebuilt. Adjustment will not take long and the small screws may have to be "tweaked" after the engine has warmed up and been running for a few minutes


Instructions


1 Identify the two-fuel adjustment screws on the side of the metal carburetor. One screw is labeled "lo" and the other is marked "hi". The "lo" fuel screw is for when the engine is idling. The "hi" fuel adjustment screw regulates the fuel when the engine is at full throttle.

2 Turn both of the screws, gently, in a clockwise direction to seat the base of the screw inside the carburetor. Do not tighten the screws with any form of a forceful nature. When dealing with these small carburetors "finesse" is a key word for beng really-really gentle but accurate.


3 Open the fuel adjustment screws in a counterclockwise direction one and three-quarter turns to two full turns. This is the starting point for all Walbro fuel screw adjustments.

4 Start the two-cycle engine. Allow the engine to warm up for approximately one minute to two minutes. The engine may be running a little rough, that is normal until final adjustments are made.

5 Hold the throttle wide open for full engine acceleration. Adjust the "hi" screw until the engine smooths out. In other words, the engine should not be missing or have any hesitation. In most cases the "hi" fuel screw will not have to be turned more than a one-quarter turn in either direction.

6 Allow the engine to return to an idle operation by releasing the throttle. At idle the engine should be running smoothly. Quickly depress the throttle again. If the engine hesitates open the "lo" fuel screw to a quarter turn counterclockwise. Perform the release and depression of the throttle a few times. The engine should go from idle to full RPM in a smooth progression. If the engine pops heavily at idle, when coming down from a full throttle, the "lo" fuel screw is delivering too much fuel. Turn the "lo" screw in a clockwise direction using no more than quarter turn increments.

On some of my 603 carbs I remove the choke from the carb and put the v-stack w/built-in choke installed in its place....You have to JB Weld the holes in the carb closed too.....The 813 carbs dont have chokes at all so a v-stack w/built-in choke will always be needed......
 

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Like CAM2 I take the OEM choke plate out on some and use a V-stack choke setup. That carb has an internal choke w/ red level. It blocks the front of the carb opening.
 
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