Mend > Motorcycles

Aprilia sr50 loses power?

My sr50 starts and seems to run well but when I,m riding it seems to lose power when I come to go up a hill. When back on the flat it slowly stutters back up to full power/speed. Downhill it runs ok. It is fitted with an arrow exhaust and used to run great. It is as if it is losing power when under more load.
This started to happen after having it serviced and new belt fit because the belt snapped.
Wondered whether it could be the rollers worn, or could the timing have been altered.

Tom B
January 2011

Aprilia Aprilia SR50 Vehicles, Motorcycles Starts Hill Flat

dale521 the IGNITION timing can go out if the woodruff key shears on the magneto which allows the magneto to move on the crankshaft and then the raised part of the magneto that triggers the pulser coil will make the triggered pulse earlier or later then it should therefore putting the timing out.and also the cdi unit can start to discharge earlier then it is supposed to if the capacitors values change through use.i have seen it on several bikes before

adam bike doctor(of milton keynes motorcycle centre)
January 2011

to be honest it sounds like the belt is too short thst they have fitted and now its in a state of higher gearing than it should be,if you take the transmaission cover off the belt should be just below the level of the edge oif the clutch pulley on the right .if its any more then 3mm below it i would say the belt is too short.whcioh will makw it struggle to pull away and also make it slow going up hill as the engine will labour when it should be revving to make peak power.

adam bike doctor(of milton keynes motorcycle centre)
January 2011

right there is no timing so dunt worry over that but yes your rollers may be egged or worn i would recomend changing them then see how it goes

dale521
January 2011