2005 Honda Activa will not accelerate past 50 km/hr

driving in over drive mode actually is what gives the economy as the engine rpms will be around 300 less than direct drive . Lower rpms = fuel savings
OD should come in around 60 klm/hr and drop out at around 50 klm/hr. When you are accelerating hold the pedal in a set position and watch the rev counter (rpms ) and each gear change you will see the rpms drop and then build back up as the vehicle speed increases At 100klm/hr the revs should be around 3200 rpms or less but if over ( say 3500 rpms) then may be the OD is not coming in. One way to test a box operation is to find a speed shop with a dynomometer and test the gear selections against loads and engine rpms

Make Your Mileage good by these Steps
use tubeless tyres
make your air/fuel mixture lean
change the engine oil , gear oil
change the air filter
change the spark plug if necessary
check free movement of brake liners
use recommended tyre air pressure (depends on tyres)
use only normal fuel ..do not use premium fuel it is not recommended
check your battery too...
And Drive at 30-50 KMPL thats the economy speed

Karan Bharadwaj
8090406090
9807237270
http://www.grins.co.in
http://www.jokesms.asia

Hi, You don't need to get much. Just change the spark plug and oil the chain if so equipped.
Change the oil too and have a nice trip. Good luck.

Hi,

Sounds like you need to tune your carburetor and check the spark plug.
Try checking the CDi, replace it with an aftermarket racing CDi and compare the ignition and combustion, if it still doing that problem.

Tell us afterwards to guide you more of these problems.

1.check for the air filter to be cleaned.
2. spark plug is correct.
3.drive at a speed of 45-50 kmph.
4. do not over accelerate.
5. clean the fuel filter and carburetor cleaned properly

check the geer oil

change the drive ratio, you will loose a bit of top end speed but it will accelerate faster. easiest thing to do short of changing out the engine for a bigger one

This may been an ignition module or a MAF sensor, this car may need to be diagnosed using a OBD I computer code reader to accurately diagnose the problem.