4stroking at w.o.t.

D

decou23

New Member
I have a 2strok 66cc that has been brokin in for a while and the only prob. I have is that I 4strokes at w.o.t. and I've tried moving the clip and playing with the screw on the carb and nothing seems to help...any idea
 
It is your main jet its too large you will need to make it smaller I show how to do this on my sticky posts somewhere. I do not know of anyone selling different size main jets right now.
soldering shut and re drilling the main jet is easy if you have the tools to do it with. find out the size first then go one size smaller.
stock is usually 0.70mm so the next smaller would be 0.65mm.
that size is around 0.026 so the drills are going to be very small and you will need to use a pin vice which is a hand held and hand powered type of drill bit holder. You can get these pin vices at most hobby shops and maybe even the micro drill bits.
 
decou23,
You can try to turn off your fuel on a long stretch of road. If you 4 stroking clears up momentarily then what Norm said is the problem. Turning off the fuel will lean out the mixture as the fuel in the floatbowl is consumed. It will eventually kill the motor by getting too lean. Soddering the jet and drilling it to a smaller size is not too tough and will help you out.

Rich
 
Norman said:
It is your main jet its too large you will need to make it smaller I show how to do this on my sticky posts somewhere. I do not know of anyone selling different size main jets right now.
soldering shut and re drilling the main jet is easy if you have the tools to do it with. find out the size first then go one size smaller.
stock is usually 0.70mm so the next smaller would be 0.65mm.
that size is around 0.026 so the drills are going to be very small and you will need to use a pin vice which is a hand held and hand powered type of drill bit holder. You can get these pin vices at most hobby shops and maybe even the micro drill bits.
Click to expand...

I have gone down to .024 and still it is running rich (32:1 ratio), if I go down much smaller will just starve out or will it burn up because of not enough lub? Sorry, I kind of jacked the thread...

Q
 
If its running rich then you need to lean it out unless something else is causing it to run rich like a sticking float.
 
Norman said:
If its running rich then you need to lean it out unless something else is causing it to run rich like a sticking float.
Click to expand...


when you say lean it out are you saying that the mix needs to be leaned out or the carb, I do not believe the float is sticking, everything seams to be clean and free in the carb, would bending the tabs for the float work?

Q
 
Lean/Rich and Fuel/Oil ratio are two different things.( They are somewhat related) Stick with the recommended oil ratio. Lean or Rich means the amount of fuel to the amount of air going into the motor. This is done by the carb. At WOT the jet is handleing the fuel/air ratio. At lower throttle settings it's the jet and the little needle that handles the fuel /air ratio. Too Rich(jet too big) means the engine can't effectively use all the fuel that it's getting. Too Lean(jet too small)brnot means that there is not enough fuel.

Don't change the oil ratio until the recommended time interval.

My $.02

Rich
 
Running fat at the top is a good thing for these 2 strokes being that having it run lean and mean on top will shorten the life of the motor. If you can live with this, then leave it and let the motor live..
 
Hi there,

I have a similar problem..

When i go at WOT, climbing up a road, the motor is perfect and pulls very good, but 4 or 5 seconds later, he starts going down (like when we kill switch), but im WOT..and 2 or 3 seconds, he goes up again, and down, and up..again..its weird..i dont know :(
 
With such primative carbs it will be really tough to get it perfect in all throttle positions. Try to get the best you can. Like Dax said, it's best to be a little rich then a little lean.
 
if your engine looses power when wide open then the level of the fuel is too low in the float bowl caused by either an incorrect float level or a restriction in the fuel line.
it could be a small amount of trash in the tank strainer if you have one or in the on off tank valve.
any part of the fuel system can get a bit of trash in it and will restrict the fuel flow.
My guess is your float is set a little to low and at wide open your surging due to insufficient fuel in the float bowl.
 
Yup. Normal 4 stroking at least on mine, acts like this, open up throttle pulling up a hill, it runs great, no 4 stroking. As the bike motor starts to come out of it's "work" pulling and beginning to "coast" the 4 stroking begins again. In other words, under load it is running best. At WOT running hard, it will cycle in and out of 4 stroking as the load changes.

This is where I find most reliability as stated earlier in the post.
(running 24:1 Bell Ray synthetic HR1) NGK plug.

Robert
 
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