How to remove back tire to fix flat on a Nishika bike

SOURCE: How to repair a flat tire?

Finding the hole can be a huge hassle, in order to find it you should try ikecur instructions.
But if you want fast repair you should buy a new spare tube and install it.
Here is a great instuction guide on how to do it: http://www.jimlangley.net/wrench/flattiretwo.htm

good luck

SOURCE: push bike tire

Inner tubes commonly lose air when stored for as little as a couple of months and quicker when cold. They also tend to dry out and leak as fast as you can pump. Replacement tubes are available at bike shops and even less than $6.00 bucks at Wal-Mart.

To replace(The long version,cause the short version not good):
Remove wheel from bike, trike, trailer, etc. and deflate tube completely. You will need 2 box end wrenches (the ones with the closed ends, because these are not sharp). Insert box end of wrenches next to each other between rim and and one wall of tire, now pry the wrenches back so as to pry one wall of tire to the outside of rim, now alternatingwrenches, slide wrenches away from each other to slowly walk one wall of tire outside of the rim, reach in and grasp old tube and pull it out. Now straight new tube out remove plastic fill cap(put cap in your pocket), reach in and insert filler into hole in rim, now working your way around with your fingers to push tube up into tire(carefull not to let it get twisted), now put cap back on tube so you don't loose the filler, now work your way around with your fingers to push tire back into rim, you may need to use the box end of the wrenchto help pry the last bit of tire back in(Just don't pinch the tube between wrench and rim while doing this, lest you now have a new hole to fix), now grasp filler so you don't loose it, add air to amount shown on tire, and RIDE ON!

SOURCE: fix a front flat tire on a mongoose varial bike

The first step is to remove the wheel assembly from the bike. Once that is done insure all the air is removed from the tube by holding in the needle on the valve stem. You may have to remove the cap from your valve stem first. Next, using a flat blunt tool, pry the inside lip of the tire away from the rim and hold down the tool. Make sure you don't have the tube pinched with your tool. Next, using a second tool, repeat the first step about 6" from the first tool. This should start the tire to come off the rim on the side you are working on. You should now be able to pull out the tube and inspect for holes. Use a simple tire patch kit if you can or simply replace the tube.

To replace the tube, remove the valve stem cap and insert it from the tire side through the hole in the rim for access. Replace cap on stem to help hold valve in place. Carefully lay tube inside tire without folding it. You may have to bunch it up a bit. Start pushing tire edge back around the edge of the rim. When you get almost to the end it will get tough to if the tire is tight.Use your blunt tool to help it over the edge of the rim. Once the tire is on, make sure the valve stem is pulled up tight and straight before refilling with air. Inspect the tire to make sure it is seated on the rim all the way around on both sides. If not, release air from tube and make adjustments and refill. Replace wheel on bike and enjoy your day!

Big Daddy

SOURCE: how to remove the rear tire with shaft drive

Pull the rear axle, and spacer on the brake side of wheel. Un hook brake rod and brake strut. Position yourself on the brake side of the bike and pull the rear wheel straight out of the final drive housing. Put a little grease on thhe final drive splines upon reinstalling the wheel to aid removal next time.

SOURCE: schwinn roadster trike back tire went flat and needs repair

buy a tire repair set from wal mart and repair the problem.