CDI box swap from '81 yz465 to '81 yz250?

C

cleopatrisha

Member

Dec 16, 2006

86

0

• Sep 5, 2007

• #1

before I purchase one I found off a 1981 yz465 for my '81 yz250. will it work?

 

7

76GMC1500

Uhhh...

Oct 19, 2006

2,142

1

• Sep 5, 2007

• #2

The rpm ranges of the engines are way different which would probably mean the advance curves would be way wrong and the rev limiter also incorrect.

 

2

2 strokes for life

Member

Jan 3, 2007

1,860

0

• Sep 5, 2007

• #3

cleopatrisha, try bikeboneyard.com for the CDI box for your bike.

 

C

cp380sx

Member

Jan 12, 2001

274

0

• Sep 5, 2007

• #4

It will most likely work. Back in '81 I raced a YZ125H and we used a yz80 black box on that bike.

 

2

2 strokes for life

Member

Jan 3, 2007

1,860

0

• Sep 5, 2007

• #5

cp380sx, think about how a 125 and 80 make there power. It is fairly simaler but a 465 makes a ton of power everywhere. 80 and 125 are alot more alike then a 250 and 465.

 

C

cp380sx

Member

Jan 12, 2001

274

0

• Sep 7, 2007

• #6

I still think it will work fine. Displacement doesn't really change the ignition curve requirements that much at all. If anything, the 465 has a little less advance at lower rpm. That would be a good thing with modern unleaded pump gas. It's not like anyone is racing their '81 YZ250 for money so squeezing every single pony out of it isn't that big of a deal.

 

F

fatboy570

~SPONSOR~

Feb 19, 2000

94

0

• Sep 13, 2007

• #7

I found the 81 YZ 465 cdi will interchange with the 81-2 IT 465, 80-81 YZ 465,and 82 YZ 490. Hope this helps

 

F

fatboy570

~SPONSOR~

Feb 19, 2000

94

0

• Sep 13, 2007

• #8

The cdi for the 81 only shows for 81 on Zedder