My dtr125cc has got a good spark but it only sprks once or twice then theres no spark for the next 4 or 5 kicks it will fire but not start

SOURCE: bike only fires once

Okay, let's have a look at it. Say Ahaaa.
The probable cause of the problem is not the spark. Get a fresh set of Stock NGK spark plugs, ground the plus to the engine, and check each cylinder for spark as the starter button is pressed for 3 seconds or so. I will wager that the spark is present.

The likely problem is the fresh gas was put into a very rusty gas tank. Bits of rust now inhabit your carb and are having fun plugging up the carb. Look at the gas valve. With a little luck there is a small bowl behind the valve. Remove it and tell me what you see in the bowl.

SOURCE: 04 crf450.hard start when cold(25deg).kick for 10min.once it

1. First thing is when was the last time you had your valves adjusted
2. On cold start up twist about 15 times on your throttle, as you do that the accelerator pump in carb will shot gas in cylinder, I have a 2003 yx426 & 2005 yz450 have to do to both of them when cold out to get started

SOURCE: i have a offroad dtr

Check the wiring exiting the crankcase up to the rectifier/CDI unit and ignition coil. Look for excessive squashing, pinched or burnt (very stiff) wiring. Check all connections are firm and free of corrosion. Ensure plug lead is not arcing to frame or engine when in place. Make sure ingition coil is FIRMLY earthed at mounting point. A good tip is to run an earth wire from the head bolt to the frame. Thoroughly check any "kill switch" wiring as moving handlebars, throttle cable etc whilst kicking over may interupt electrical circuit. It is common for wiring to eventually get caught up in the steering "stops" on the lower fork clamps, cutting or severely damaging wiring. The wires exiting the crankcase come from the generator and without a rotor puller they will remain unsighted behind the generator rotor. You can easily remove the cover however, and check grommet where loom enters for pinched or flattened wires.
Check the site below (scroll down for your Model/Year) It has exploded view diagrams of all the pertinent parts to see your bike going again. Cheers.

http://www.cmsnl.com/yamaha-motorcycle_model16707/

Testimonial: "my dtr 12c 1998 sparks the first 3 times i kick it then it dosnt"

SOURCE: '97 rstd cold start, full choke,, cyl 3&4 do

low milage tells me most likley the carb is gummed up. You may need to remove and clean out or try some fuel injection cleaner. Use twice as strong as recommended. Your description points to not enough fuel when cold which is when it needs the most. If your handy I would remove the bowl and blow out all chambers and tubes with brake cleaner.