Hey everyone, I had just finished building my new bike and I have been riding it for 3 months. During the three months I have noticed an increase in 4-stroking when I ride. It used to be mostly at top end (WOT). Now it is four stroking all the time? I cant seem to fix it. I put an in-line fuel filter on, I tweaked with the c-clip in the carb on every position, and it doesn't work? I'll include a picture if you want to point out any concerns.
Is my 2-stroke fried???
- Thread starter Masor
- Start date
I've never heard the term 4 stroking, please explain. If you haven't been mixing too much oil in your gas then like was said check the plug, check exhaust isn't plugged, then make sure spark is strong and plug fires strong still when warm. Often when an ignition is going bad it'll get weaker as the bike warms up. The plugs that come with these engines aren't always the best either.
The other thing it could be is if your reeds are bad, cracked, gummed up, or have something stuck in them. If you've been using gas that may have had even the tiniest bits of dirt or grit or anything in it from say a can for a lawnmower, you might want to check the float valve on the carb to be sure it's not stuck.
2 strokes fairly new like yours aren't likely seriously damaged, especially if it turns free and you have been using 2 stroke oil, and they're cheap and easy to fix you just have to narrow it down. If it has good compression then the reeds are fine, and the piston/cylinder is fine, if it has good strong spark when warm then the plug and ignition are likely fine.
btw cool bike
The other thing it could be is if your reeds are bad, cracked, gummed up, or have something stuck in them. If you've been using gas that may have had even the tiniest bits of dirt or grit or anything in it from say a can for a lawnmower, you might want to check the float valve on the carb to be sure it's not stuck.
2 strokes fairly new like yours aren't likely seriously damaged, especially if it turns free and you have been using 2 stroke oil, and they're cheap and easy to fix you just have to narrow it down. If it has good compression then the reeds are fine, and the piston/cylinder is fine, if it has good strong spark when warm then the plug and ignition are likely fine.
btw cool bike
Last edited:
Al.Fisherman
Active Member
motorpsycho
Active Member
once again, the clip position on the jet needle does nothing at w.o.t. it only affects the mixture from idle to about 3/4 throttle.
these engines do not have reed valves (as nwohater mentions).
a stuck float will not cause 4 stroking, a stuck float will result in either A. the engine will not get any gas and will not run, or B. the carb will flood over and spill fuel all over the place.
first thing i would do is make sure that the choke isn;t partially closed. the choke on an n.t. carb is very simple and they can vibrate loose. If you have a cns carb, the choke is more like an air bleed and you will have to make sure that it's closing all the way when you turn the choke off.
then, i would pull the float bowl off and look at the main jet. the main jets on these carbs have been known to vibrate loose and fall out into the float bowl.
check your air filter, make sure it's not plugged up.
if your engine is 4 stroking you are not getting enough air....like the choke is closed, air filter plugged or the jetting is too rich (too much fuel, not enough air).
i have found that 80% of getting these engines to run right is in the tuning of the carb (re-jetting). also, a better exhaust will help you out too, like an expasion chamber, the stock mufflers plain suck, and they will plug up over time.
these engines do not have reed valves (as nwohater mentions).
a stuck float will not cause 4 stroking, a stuck float will result in either A. the engine will not get any gas and will not run, or B. the carb will flood over and spill fuel all over the place.
first thing i would do is make sure that the choke isn;t partially closed. the choke on an n.t. carb is very simple and they can vibrate loose. If you have a cns carb, the choke is more like an air bleed and you will have to make sure that it's closing all the way when you turn the choke off.
then, i would pull the float bowl off and look at the main jet. the main jets on these carbs have been known to vibrate loose and fall out into the float bowl.
check your air filter, make sure it's not plugged up.
if your engine is 4 stroking you are not getting enough air....like the choke is closed, air filter plugged or the jetting is too rich (too much fuel, not enough air).
i have found that 80% of getting these engines to run right is in the tuning of the carb (re-jetting). also, a better exhaust will help you out too, like an expasion chamber, the stock mufflers plain suck, and they will plug up over time.
motorpsycho, I adjusted my float because it used to overflow, now its fine. And as for the choke, I took it off because it would loosen after every ride and shut my bike down. I screwed in both of the jets fairly tight and put a smaller main jet in. I don't run an air filter anymore; instead i built a scoop, like on some cars, and put a screen at the opening. What I'm suspecting at the moment is either the spark plug, or the fact that my carb is not level. Or maybe because i have 850 miles on it.
motorpsycho
Active Member
both jets?
these carbs only have one jet.
if you're running a scoop with a screeen that will eliminate the plugged air filter theory.
your carb not being level could possibly have something to do with the problem. but if the carb is in the same position now as it was when it didn't 4 stroke, then i doubt that it;s the problem.
these carbs only have one jet.
if you're running a scoop with a screeen that will eliminate the plugged air filter theory.
your carb not being level could possibly have something to do with the problem. but if the carb is in the same position now as it was when it didn't 4 stroke, then i doubt that it;s the problem.
Similar threads
- Solved
