CDI Interchangability?

Blundey · Post by **Blundey** » Sun Mar 25, 2007 12:39 pm

Hi guys i got an L5 that needs the cdi changing...when getting a new one do i NEED to match the serial exactly or can i use the cdi from say an L4 or L3 or something...they codes are different ...but will it affect the bike.?

cheers for any help

RedexRobB · Post by **RedexRobB** » Sun Mar 25, 2007 12:49 pm

Hello mate and welcome to the forum

I dont know for sure but i think you can swap them. Ive lent my CDI unit to another member here before and both bikes were completely different years.

Blundey · Post by **Blundey** » Sun Mar 25, 2007 1:01 pm

if any one can confirm that would be great. Thanks

RedexRobB · Post by **RedexRobB** » Sun Mar 25, 2007 1:32 pm

it did work by the way, i didnt write that in but it worked perfectly.

Blundey · Post by **Blundey** » Sun Mar 25, 2007 1:37 pm

thanks mate, but they are very expensive down here....and id rather have a definate answer bfore i

up the cash for a replacement.

RedexRobB · Post by **RedexRobB** » Sun Mar 25, 2007 1:49 pm

fair enough, where abouts are you?

Blundey · Post by **Blundey** » Sun Mar 25, 2007 2:38 pm

bedfordshire

RedexRobB · Post by **RedexRobB** » Sun Mar 25, 2007 2:54 pm

cool, im in hertfordshire at the moment at the uni. Keep an eye out on ebay, sometimes they come up cheap. Why is it you need to change the CDI?

Post by **Northern ANdy** » Sun Mar 25, 2007 8:19 pm

as all the coils and engines are the same since 1989 they should all interchange I would think

zxrtbone · Post by **zxrtbone** » Sun Mar 25, 2007 8:20 pm

what does the cdi unit actually do

Post by **Northern ANdy** » Sun Mar 25, 2007 8:22 pm

the pick up coil is telling the cdi the cranks position, and the cdi then works out when to fire each coil to ignite the correct cylinder. It also controls how long the coil is charged for.

zxrtbone · Post by **zxrtbone** » Sun Mar 25, 2007 8:26 pm

ok cool,if you had a dodgy cdi unit how would that affect the bike?

Post by **Northern ANdy** » Mon Mar 26, 2007 8:56 am

it depends how it fails, sometimes it will only affect the top end revs, or wont run at all.or be down one a cylinder or two

Post by **zimm** » Mon Mar 26, 2007 1:06 pm

all L model cdi's are interchangeable, as are H models, but you cant put an H on an L or vice versa as the ignition rotor lobe spacing is different.

SP cdi's (L model) have a different advance curve, but also require(?) a TPS and flatslides.

the UK spec L model CDI (which has serial number 1332) has no speed restrictor circuitry so will allow you to exceed 180kph without an MMax derestrictor, or kph/mph converter

Post by **masterofinsanity** » Mon Mar 26, 2007 1:55 pm

thanks for that Zimm i have created a new post from this in FAQs