Swapping earlier CDI into 2008 yz450f

I did a little searching on this topic, but want to double check before I start looking on ebay. If I'm looking for more low end power can I swap CDI from 2003-2006 models into my 2008?

 

I found this comment from Gray, but want to be sure it applies to my 2008. 

"Usually, yes.  An '06 is 2S2-85540-00-00, an '03, 5TA-85540-00-00, '04 is 5XD-85540-00-00, so on.  Since all 85540's are CDI boxes, the part itself will usually only be stamped as 2S2-00, or 5TA-00. 

 

The two sets of zeros after the basic part number (85540) indicate significant revisions, alternate sizes and the like, and the second pair for less significant changes.  The '07 part number is 2S2-85540-70-00, so that CDI is stamped 2S2-70."

I did a little searching on this topic, but want to double check before I start looking on ebay. If I'm looking for more low end power can I swap CDI from 2003-2006 models into my 2008?

Those CDI's from those years are a direct swap into your 2008.  I would avoid the '05 CDI because Yamaha remapped it for that year and the 2005 yz450f is a dog compared to the '03 and '04 bikes.  The 2006 from my research (not personal experience) is the best all arround map, great low end, more than the '08 CDI.  And revs out better than the '03 and '04 CDI's. 

I would avoid the '05 CDI because Yamaha remapped it for that year and the 2005 yz450f is a dog compared to the '03 and '04 bikes.  The 2006 from my research (not personal experience) is the best all arround map, great low end, more than the '08 CDI.  And revs out better than the '03 and '04 CDI's. 

 

Entirely true.

Thanks for the info.

 

Just scored an 04' cdi on ebay for $29

 

That's an affordable mod :)

Edited by RMBurrr

Those CDI's from those years are a direct swap into your 2008.  I would avoid the '05 CDI because Yamaha remapped it for that year and the 2005 yz450f is a dog compared to the '03 and '04 bikes.  The 2006 from my research (not personal experience) is the best all arround map, great low end, more than the '08 CDI.  And revs out better than the '03 and '04 CDI's. 

From my experience the 08 will not rev out better than the 03 or 04. The 03 04 has way better low end but still revs out.

From my experience the 08 will not rev out better than the 03 or 04. The 03 04 has way better low end but still revs out.

I said that the '06 revs out better not the '08. And grey says the '06 revs out better than the '03 and '04

The map is oriented to that, yes.  Depends a little on cams and the individual engine.

The map is oriented to that, yes. Depends a little on cams and the individual engine.

I missed the post where the timing curves were posted. Sure feels like my 09 has way more grunt with the 03 cdi and has lost nothing on top. Please repost timing curves.

I'm looking for a little help on this as well.  I just bought an 08 and will be using the bike for single track and some other trail riding.  Would the 06 CDI be a good mod to give me some extra low end power?

I'm looking for a little help on this as well.  I just bought an 08 and will be using the bike for single track and some other trail riding.  Would the 06 CDI be a good mod to give me some extra low end power?

Yes the 06 will help the low end more than the stock cdi. The 03 or 04 will be even better than the 06. After more riding my son in-law pointed out that when he was drag racing friends on flat ground he felt like the 04 did not have the over rev like the 06.

I went from the stock 09 cdi to the 06 and it felt magical. More low end but manageable. When I installed the 03 I was in heaven. Even a little more bark but I still felt it was manageable. I ride mostly single track and like lots of low end bark but not as much as the fuel injected KX450that I rode. I think either the 03/04 will work fine for most if top end is not critical. If it is then the 06 is probably the right choice.

I also would like to state that we did install the DR D pipe before we did these cdi mods and have no idea how they would work with the stock restricted pipe.

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