help with cdi

[auroraglass]

ok i have a 85 250 big red i have been using a cdi of a 200 trx i switched the plug from the round one to the 2 square one , my problem is i have bought 3 cdis off ebay used and no of them work on my bike the all said came from a running bike , 86 87 same plug . i thought the 85 was basicly the same is there something in the electric thats diff or did i get 3 bad cdis ? thanks for any info .

[kb0nly]

The 85 is a one off year for the CDI... Or so i have been told. It has electronic advance built in. I haven't ever worked on an 86 or 87 but there has been some other posts on here from others that said they had the same problem trying to swap on a later year CDI.

[auroraglass]

i thought the electrical was the same just a diff style plug ?