Query Approved.

re:

might be air filter problem,

check spark plug for proper gap.. Generally i have seen an eroded plug electrode do this.

rings can cause a blow by to happen, but then your vibrations would go up since the piston would knock against the cylinder walls.

@Satya_3d - Thanks for the pointer; Air filter is a genuine stock replaced less than 2K Kms & is very clean.
@JD - Thanks so much for your support man; The plug is really not so good one, but the mech didn't complain anything on that & he did some adjustments besides the carbs tuning on Tuesday; what he really insisted was that rings are slightly erroded; Are you serious that it could be the reason? I don't mind replacing them RIGHT NOW; However, my question still remains - how could the rings get erroded so easily, I mean just for about 7.5K? Hope its time to move from ELF to something else, but definetly NOT MOTUL.

One more update - If I open up the the throttle little more than required (not full), the jerks appear little late rather than immediately after closing the throttle; I could be completely wrong in theory, but this this is the best explanation I could give to demonstrate the problem

If I give the right amount of throttle, I feel that the engine gobbles up all mixture & the cylinder asks for more fuel or air; If I provide provide slightly more than the required throttle & close it, there's a reservoir kind of stuff where the additional air+fuel is available & when I close it, the bike is smooth until the cylinder consumes the entire mixture in the reservoir; now if I open up the throttle completely & close the throttle, it appears as if I opened up the choke causing the idling to increase for few seconds, like again until the reservoir is emptied up. In all the cases, the engine stops after 15-20 seconds after idling & also as I told before, the idling is also not constant tune.

Hey aargee,

even i had faced a similar issue like yours.
my mechanic has cleaned and tightened a part which is screwed or bolted near the handle cone. i dunno wht it is called. i ride an rx-100 so i even dont know whether it will be the same for your bike. that part he cleaned for any rust. also he emptied my fuel tank. gv full pressure wash to remove any dirt inside so that the carburettor doesnt get clogged with it. then he cleaned the petrol filter knob. then the carburettor, finally the air filter with oil. and then my bike had a smooth ride.
even i need to change the piston rings as well as the main engine bearings. but my bike doesnt give me any kind of jerks.

kindly check and see if this helps. also for a safe side jus change to a ngk spark plug for your bike. they are really good ones. My bike has an iridium spark plug.

^^^ Thanks for the tip, I'll apply all the relevant points that you've shared.

did your mechanic adjusted the carb for better mileage? may be the needle is kept too low.
problem with the fuel flow
this can be due to a wrong adjustment of the carb float ,airlock in the tank or faulty fuel tap
faulty plug or ignition coil
water in the ignition switch (spray WD40)

do a check of the above.good luck

Nope

Will check on these points

Well I'll check for faulty plug & ignition coil;
Water in ignition switch - by now it would've been vapurized due to the summer heat

Thanks for your pointers Satish

my self being an automobile enggr.i too face prblms like this wit 2 strokes.it is the main prblm wit the petrol u use and the tuning of the carb.change ur petrol bunk and set the carb wit a good skilled mech.

aargee, replace sparkplug once.. and then check operation.

Sure sure, I'll do that first thing when I go home this evening; also pls advice me on the gap (let me be double sure)

The gap should be 7(not sure about the value is in mm) if it is NGK BPR7HS. I have seen mechanics have some measuring gauge to know the gap is correct.

@JD - Buddy - Just back from a 2 Km ride after changing the sparks & YES, there's a difference definetly; as of now the jerk's intensity has come down little, but still some more to go; may be I'll try adding excess oil or play with airscrew; what do you think. Thanks man, this is much better than what it was this morning.
The manufacturer

The model

The company spec width

From what i read, the gap setting of the boxed plug, need not be right for your bike. That model plug is probably meant for many models of engines. You have to set your engine's gap after you buy the plug, if you haven't already. Maybe that will remove the remaining jerks.