Convert my yezdi from kick start to self motor start

May be bad fan motor.

If it fits then why not. Silencers are only used to even out the power pulses in the exhaust and they do this by a bit of back pressure or padding in the construction of the silencer.

Check the connection of wires onto the battery terminals are not lose, wiggle them, they should not move. Check the large wire from the negative side of the battery to the bike frame, check its got a clean connection at the end that bolts to the frame.

The question is not very clear, If you meant that the engine does not fire with the self starter but works fine with the kick start then the fault is the starter motor or the BATTERY. A poor motor brush, bush can have a strain and so will not have the RPM but might drain the battery with a high current so that the firing voltage will be affected. Also a weak battery will have a similar effect and so the ignition will not get the required voltage. If so cross check battery and motor as these are the suspects.

put premium gas in it to help clean/start it better take the spark plugs out spra a little starting fluid on the plug stick it in then kick the bike a few good times it should start and run a little better i suggest puting some lucus oil in the gas also to help...the self motor shouldn't cost to much if you do it yourself you will save a bundle let me know if this solves your problem

check complaints with the self starting switch . then check the starter fuses , then check for wiring fault or disjointed wire connections towards the starter motor ... Hope ur getting ur activa started with kick start .... Have a happy day

change fan

NO neeed of authorised service center. jst remove oil cover after draining out oil. fit d motor in the hole facing towards alternator housing. refit d oil cover. fit motor with 3 screws. then open alternor housing using T- spanner. addd those two tooooothed wheels n jst install all d wiring.
Warning:::--- If u something about bike engine. then n then only do this.