So when I first got my kit it worked great, powerful fast, But like thesecond day I got it everything just seemed to degrade. I was breaking it in at 24:1 Put on a sbp exansion chamber. My bik hits top speed of like 5mph I can pedal faster han it wants to go. I don know what the problem is. Please help.
Lost alot of power
- Thread starter clashed13
- Start date
To start tell us what you have, 48 cc or 68cc and what you have tried to correct the problem. Which carb you have and someone will help.Greg
Check for air leaks, at the carb and head and cylinder. Does it idle ok? Have you tried a different spark plug, the stock plugs are not the best.
What color is the plug? Adding an expansion chamber will usually cause the engine to run leaner...you probably should have waited until after break in to start adding stuff.
If all you changed is the exhaust then Joe is right, but if you raised the clip (made the needle longer from tip to clip) and it runs better it sounds like it is rich. When you say stock carb is the choke on the carb or on the handle bars?
Last edited:
There are 4 different "stock" carbs that came with these engine kits, depending on the year and the vendor.
We would like to help you out, but we need more detailed information.
Can you post a picture of it?
We would like to help you out, but we need more detailed information.
Can you post a picture of it?
Ok, it sounds like you have an NT carb.
If you moved the clip towards the first notch as in the notch on the top and not the first notch on the bottom (which first are you referring to?) and you are still running rich aaand this all changed suddenly, I would check to see if the fuel jet had not come unscrewed from the bottom of the needle jet (some call it the jet tube or jet holder). If this is not the case and you are still running too rich then a re-jet or solder and re-drill is in order.
FWIW, dark brown is a good color for the spark plug.
Charcoal black is too rich and anything lighter than chocolate milk color is too lean.
If you moved the clip towards the first notch as in the notch on the top and not the first notch on the bottom (which first are you referring to?) and you are still running rich aaand this all changed suddenly, I would check to see if the fuel jet had not come unscrewed from the bottom of the needle jet (some call it the jet tube or jet holder). If this is not the case and you are still running too rich then a re-jet or solder and re-drill is in order.
FWIW, dark brown is a good color for the spark plug.
Charcoal black is too rich and anything lighter than chocolate milk color is too lean.
You'll probably think this is crazy, but check and make sure your gas cap is venting. A lot of them don't.
The symptom is, it runs good for a short distance, and then loses power.
When we say rich or lean we are talking about the air to fuel ratio going through the carb into the engine, what most like to do is use a new plug after changes to get a good read. Like I asked before, is changing the pipe all you did?
One more quick check is the spark plug gap, 26 to 30. Most say .28 is about right. You may want to check the jet, sometimes they are not tight and vibrate loose.
Last edited:
LikeGreg58 said, we are referring to the fuel/ air mixture, trying to help you get the carb tuned up properly. This has nothing to do with the oil ratio.
FWIW, use 24:1 fuel/ oil ratio for break in, 32:1 thereafter.
After the engine breaks in it will most likely need to be re-tuned as the seal between the piston rings and piston improve, engine becomes more efficient at burning the fuel, and power increases.
FWIW, use 24:1 fuel/ oil ratio for break in, 32:1 thereafter.
After the engine breaks in it will most likely need to be re-tuned as the seal between the piston rings and piston improve, engine becomes more efficient at burning the fuel, and power increases.
After the engine is fully broken in, put the expansion chamber back on and then re-tune the carburetor for the different fuel requirements to get the full, safe, effect of the expansion pipe. You will like the performance enhancement of the expansion chamber for sure!
Try moving the clip DOWN to the second from the bottom and see what happens. You may also want to start with a fresh plug.
Last edited:
I have lost power. I have a 66cc with and expansion chamber a .70 jet, a 40 tooth, and high perfomance wire. I run a 15 mile in <30min at 35mph. I was on my way home and about 10 miles in I went from 33mph to about 15mph. I disengage the clutch and throttle and the engine does indeed rev normal, but as soon as I put a load on the engine it bogs down and wants to die. I limped home at 15mph. I am not sure, but Im going to look at the plug first, then the coil, then the carb. Any thoughts? I wonder if it is a compression issue?
lets get tinkering!
BTW I am73 inches and 245lbs, and I got the bike up to 40mph, and it was fast!
lets get tinkering!
BTW I am73 inches and 245lbs, and I got the bike up to 40mph, and it was fast!
It does sound like compression loss, check for leaks at the head and base gaskets. I have found that a lot of parts get loose due to vibration, at the carb, intake and exhaust. If you don't find anything wrong externally check the main jet, some members have had the jet to fall to the bottom of the bowl of the carb.
