what would cause a stock cdi to blow twice

[tumbler440Ex]

i got my bike bought half a year ago and the cdi went in it so i got a stock cdi again and that blew again after i drove it for like half a tank since the last cdi?
what could cause that?
a defective cdi?

[trx400ex]

im not expert, but it could be soemthign in your electrical system....or maybe just a bad cdi..... some that knows more will help ya out im sure

[305exracer11]

is your motor modified? if it is and your running stock cdi it would cause it to go bad, get a after market cdi.

[tumbler440Ex]

i live in canada and i dont think theres that many after market cdis i can get around here i seen them in denis kirk and nacs catalog but i dont have liek 200 bucks its like almost 400 bucks give or take a little any canadain money a stock cdi only 160
my engine only has well its bored out bout 60 or 80 000 i forget now and boysan rad valve jetted and k&n air filter thats obut it and silncer

[tprender]

If you are talking about a problem on a 250R there should be no reason to put on any aftermarket CDI. You have a problem some place else if they are going bad. I would check out your stator on the R, they go bad very often. Get the manual and take a reading with a ohm meter and also check the connection from the wires that come off the stator uinder the gas tank.
People change CDI boxes on the 400EX but not on the 250R. But there was a 5 degree difference between the timing on the 86 and the 88 box. Other than that they are the same.