Loss of power no solution

If it "four strokes" when you go WOT, I would try it with the air filter box removed, but still with some type of filter.. or just drill holes in the box to let more air in. The stock air filter box is restrictive so that would richen the A/F ratio at higher RPM and WOT.
I tried it with a different High Performance carburetor which lets a bit more air in and still struggled. Will try your method though
 
may be diff than I've seen, but never was able to see all the way thru muffler - try loosening at exhaust gasket about 1/8 inch
 
Sounds to me like it may be a lean rather than rich condition as you say if you ease into the throttle it acts near normal, but if you snap the throttle open it balks. With all the stuff you have changed and worked on I'm guessing a crank seal on this one too.
 
Hello guys. Just wanted to give one last report. After all tweaking the bike in flat surface managed to go faster but if there was a slight uphill situation it will loose power drastically. I gave up on the engine and swapped it with a working one and decided to call the company for a replacement. Too much time, money and effort spent. Thank you all for your help!
 
Hello guys. Just wanted to give one last report. After all tweaking the bike in flat surface managed to go faster but if there was a slight uphill situation it will loose power drastically. I gave up on the engine and swapped it with a working one and decided to call the company for a replacement. Too much time, money and effort spent. Thank you all for your help!
I had a problem with mine one time that really had me stumped but I finally found out that the air filter was oil soaked from the two stroke oil slowly accumulated from the carburator. I cleaned it with hot water and Dawn dishwashing liquid and it restored the loss of power. Later I installed a angled filter and angled it up to prevent it from happening.
 
I’m having the same issues with mine. Worn piston rings may be the problem here
 
I think the little foam filters are supposed to be oiled. I covered mine in 2 stroke oil then squeezed out the excess. Runs fine. Without oil the big holes in the little foam disc are more like a coarse screen than a filter.
 
Hello forum. Upon doing a LOT of research I decided to open an account and ask for help. I got an 80cc bicycle engine off ebay with NT carb. It already did break in period, around 4 to 5 tanks. Mixture was 16:1 then we increased to 20:1 then around 30:1. The bike has a massive power loss. It runs top speed 15mph with luck and going uphill is more an assisted peddaling.
Things I have tried to increase power:
-moved the c clip for the needle (moving a notch up from center helped a bit)
-checked float and adjusted jet which was loose,( no change here.)
-changed fuel line which leaked and filter (no change to performance)
-changed spark plug (no change)
-checked muffler to see if it was clogged and it wasnt.
-removed muffler cap (increased power a bit but still slow to build up speed)
-tried different nt carb (no change to perf.)
-tried an HP carb (made it loose performance)
-checked and adjusted clutch
-checked magneto and voltage for magneto and cdi
-changed cdi (original one was giving a reading of 7 instead of the one it should have, changing cdi improved performance a little bit)
-adjusted every screw and cap for any possible leak and nothing.
The only thing that seemed to boost the power was removing the muffler cap and rising the c clip a notch to make it leaner. Was have 2 more bikes and one of them runs flawlessly. Has good power and goes fast. We keep switching parts between the 2 and nothing seems to improve the performance of the engine. We opened up the engine and looks fine. We do notice the engine only responds fairly to the throttle when it goes from 0 to 3/4. At full throttle if its running it looses power and decreases speed ubless taking it to full throttle very slow. Also not even at half throttle the bike has enough power to sustain speed if it goes a little bit uphill. Any advice?
It's a sick no good engine throw it the dumpster order a new motor for about a hundred bucks from a US distributor and be happy!
 
The more I mess with them the more I realize CG engines are junk. Buy a used Japanese motor with a 78mm clutch you won’t regret it. It will last thousands of miles and never blow up if you maintain it.
 
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