Weird Power Loss Issue at WOT (different from bogging)

U

userix

New Member
This is my other bike that I have built using the same type of RAW "80cc" engine kit. I am experiencing a different power loss at WOT with this build. This is what happens: I am riding at WOT and the bike is pulling beautifully with no signs of problems or bogging. Then all of a sudden, an instant power loss occurs, where the motor will almost cut out completely, but doesn't completely die. It is almost as if I am killing the engine after a ride, but if I back off the throttle for a couple of sec and then WOT, it will return to the full power state and pull really fast with no hesitation. Now, this is unlike the bogging issue I have with my Schwinn Legacy beach cruiser build, where it would waver back and forth between slowing down and speeding up. Fuel flow is fine (no restrictions), because I can WOT for 10sec without issues. No air leaks and it doesn't happen all the time I go to WOT, therefore I don't think jetting, fuel frothing, vibrations, are the causes.

Is it possible that I am maxing the CDI? What would the symptoms of maxing out a CDI be?
 
Could be the CDI, it could be the spark plug, it could be the gas cap is not venting, it could be random garbage in the float bowl messing with the fuel jet, it could be garbage blocking the fuel inlet at the carburetor between the hose barb and float valve.
Just because you can WOT it for 10 seconds does not mean that there is no problem with the fuel system. 10 seconds is not long enough. I can shut off the fuel valve and my engine will still run for a minute or so.

First just try the simple things, testing after each one is done. Go through everything and be sure all electrical connections are clean and secure (don't forget the spark plug wire and kill switch), and do an inspection of the fuel system (take apart and clean forwards and backwards). Try a new spark plug too.
 
Sorry, left out some information. After that one incident that it did that, I continued to ride for the next 15 min, WOTting on long straightways without the slightest hint of loss of power or bogging. When the power loss occurred, it felt that I am pushing the engine to its max in terms of rpm and the noise. That's why I am curious what exactly happens when the CDI is maxed out? Or what happens when the engine is topped out? It just seemed like such an isolated incident (single hiccup) in between periods of perfect riding (10min before and 15min after) with problem-free WOTs that makes me think it's a different problem. I am familiar with the two threads you guys posted.
 
When the CDI is maxed out, the engine will stop accelerating faster and faster and just hold a steady high RPM.
That acts like a governor and prevents the engine from over revving.
 
never hurts to put a copper core [ngk, nd] and a nice non chineeze plug. ever notice new cars with lights burned out? thats because their china made, even the cars from japan use them now. the nippon denso bulbs from my old toyota lasted 25 yrs when i sold it to a lawn man. prob still useing it in mexico with the same bulbs
 
Are you guys sure the engine is not just revving to the point where it unloads and starts to four stroke?
 
You must log in or register to reply here.
Back
Top