Engine swap By house (Read 611 times)

[house]

Ok I have a 49 cc Tao tao 2014.the orig motor was starting to run like poo really slow loss of power.so I bought a motor from friend was supposed to be good engine so I put it in and started it well tried but it took a min but when it did or ran like poo but I got it dialed in
And started . Runs fine at idile and revs up but as soon as the back tire hits the ground nuthin sounds like an old 1 cylinder tracktor give it gas and itdoes nothing no rev no power jus goes pop pop pop. so I take it out and put orig motor witch ran fine when I took it out jus no power.
Went to start it and it does the same exact thing runs fine until the back tire hits the ground then no throttle and I mean no throttle won't do anything. I've had 7 diff me amicus look at it and nobody can figure it out. Sum one said fuel pump tried it no change.
My friend sold the motor to sum one else they put in there scooter and it runs great no prob at all. Does anyone know what the prob mite be I'm stumped.
Please help.
Thank you

[jjoshua20213]

Sounds like a problem within the wiring harness. I had a harness go bad at it started to knock out all my electrical components. In a period of 5 months it took out 3 cdi's 1 voltage reg, and over 3 stators. The stators strted going toward the end. One day it started misfiring, then lost power the sounded like it was firing randomly not triggered to, then it went back to normal, lost power and died. literally killed every stator I put on it after that. I would change it and it would run for maybe 10 miles each time before it started going slower and slower then was too week to start next time I tried....



Point being if you tried an engine, but it worked on the other guy's frame not yours, then its something on your frame. Judging by the symptoms I would say there is a serious defect in your harness. You can get new ones for around 45 bucks and since your bike is new it would be fairly easy to find a match for your bike.


Assuming you changed the spark plug,cdi,spark plug wire and boot,ignition coil, and carb already.

[Bashan]

I agree, it sounds electrical. My guess would be coil or boot. When the tire hits the road? Do you mean when you sit on it? That could be pressing on something in the harness. If you haven't swapped electricals yet it's time.

[jerryscript]

Could be as simple as the spark plug boot. I had one begin to get loose. It was hard to start with the electric starter, but started easy with the kickstarter, I eventually found out because pushing down on the kickstarter pulled it just a bit causing it to make better contact. While riding, I would have times when I lost all power, surges and bucking like a bronco, then it would power back up. The looseness of the spark plug boot meant it only worked when vibrated into the right position, any hard bump or the right vibration could knock it loose, then it would vibrate back on. Replaced it after chasing down possibilities in the carb and elsewhere thru the system, and it has run perfect ever since.