20 Most Recent 2005 Aprilia MX 125 Questions & Answers

Dont waste your time looking for something else. Go ahead and pull the spark plug and do a compression test. It should have at least 100psi. If not,its time for a top end rebuild. It gets worse when it gets hotter because the ring gap expands,and loses what little compression it has. Best to check the compression and rebuild the top end now,before the piston or rings break,and cause lower end engine catastrophe...

low oil light

2-stroke engines misfire regularly under light loads — sounds more like a flutter or sputter..

My guess would be that at the high end you are running out of torque, resulting in a light-load condition, and that characteristic 2-stroke misfiring is taking place. If you are simply running out of the engine's ability to give more, you might be stuck with this behavior.

Best thing to do, would be to buy an aftermarket exhaust system, either complete, or just the muffler, a complete one would be better, as the header pipe is usally a bigger diameter. There are many brands to choose from, and varying prices. Put the exhaust on first, then worry about the jetting. Ride it first with the new exhaust, it may not need re jetting, depending on the brand of exhaust, the supplier should have the specs for any re jetting if needed. Mabey one size bigger on the main jet. Also, for extra performance, you need to alter your air box, or air filter system. A bigger exhaust will require more air flow intake to be of any use. Apart from that, it will sound great.

it is digital or a cable screwed into the back, check that the cable is all the way screwed in, if it is, remove it and make sure the end of the cable is square on both ends.

Most likely from underneath, you will need an extension. However have you tried a supe magnet or Dental picks. They are available cheaply or long narrow Tweezers?

have you tried turning the tick over screw in ?
carb may need cleaning ie idle jet which is the very small one located next to the main jet
try these first if no joy you may need to look at the piston and rings condition because low compression could also cause this problem
hope this helps

IF YOU CAN GET THE BIKE TO IDLE AT ALL, SPRAY SOME CARB CLEANER AROUND THE INTAKE BOOT AND SEE IF THE ENGINE REVS AT ALL. IF IT DOES, ITS A LEAKING SEAL AT THE BOOT. IF NOT IT IS PROBABLY STILL SOMETHING IN THE CARB.

If your bike starts even for 5 seconds you should investigate your fuel delivery system.Check fuel pump,filter,try spray carb cleaners like Gum Out.Most importantly make sure your choke is working.You got your ignition (spark) it is most likely fuel related.Good Luck.

plug

try changing the plug motor needs air, fule and spark to run.