Why did my r15 is bubling from behind? i experince

No, not well. The rolling radius is bigger and will make your speedo read 5.5% slower than you are really going.

A 215/55 R16 is within a 1% match (0.7%) but will give a harsh ride. A 215/60 R15 will make your speedo read 2.5% slower than actual, not too bad, and it will ride better.

check batt

1. Shaking steering wheel... typically a sign that your wheels are out of balance. If not properly weighted during a highspeed balance adjustment, they will wobble during high speed driving. Get a proper alignment and highspeed balance job.
2. Sounds like a suspension issue... however, that could be a few things you need looked at. Your shocks or struts may be worn. In addition, you may have springs that needs replacing. There are a variety of shock/strut applications that can have your car riding like a race car (stiff) or riding like a "more expensive" car (soft) and a lot in between. See your local tire and wheel specialist for more info.
Hope that helped..

Hello. Start your bike and let it idle for 10-15 min. Check the radiator fan, it should start running.
You cannot check if the radiator fan is working or not at random timings as the fan gets ON and OFF depending on the engine heat. (I got myself confused as my Bike's radiator fan was not alive even after a 100 KM run).
Happy riding with your R15!! Take care.

what you can do is fill the tank and ride it till all the gas is gone but dont hot rod it just ride it normal and you will know what you get for millage then that is really the only way

Certain patterns can cause wandering laterally on surfaces that have been grooved especially, Are the tires name brand, is the rear wheel straight, rear avle not squared to the biks causing traking issues, crabwalking, is the swingarm bearing and races good and tight? what about the steering head bearings for the front forks? the frame may be bent as well if ever crashed?

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the milege for 10000Km is 6214 Miles

Try this web site http://cycle-ergo.com/
It will let you try out and compare your riding position on lots of bikes without having to buy one first.