CDI box


37 replies to this topic
  • humpness

Posted March 09, 2011 - 09:34 PM

#21

would the upgrade from a 07 to a 06 cdi be very noticable?

  • elkjaer

Posted March 10, 2011 - 01:42 AM

#22

Do i have to rejet the carb if i mount another cdi? or is it not nessesary ? :thumbsup:

  • davidl9999

Posted March 10, 2011 - 10:35 AM

#23

Do i have to rejet the carb if i mount another cdi? or is it not nessesary ? :thumbsup:

No necessarily, but you should always check the tune after making intake/exhaust/timing changes.

  • elkjaer

Posted March 10, 2011 - 11:09 AM

#24

whats the easy way to check that, looking at the sparkplug ? :thumbsup:

  • davidl9999

Posted March 10, 2011 - 11:25 AM

#25

Just ride it and see how it feels. You might need to reset the idle speed and adjust the fuelscrew for a new idle vacuum. I doubt that you'll need to change a jet. Maybe adjust the needle if the midrange control changed for you.

  • grayracer513

Posted March 10, 2011 - 12:49 PM

#26

would the upgrade from a 07 to a 06 cdi be very noticable?

Would that be an upgrade? The '07 is softer on the bottom, but pulls harder up top. Some of that is cams, but the timing map probably contributes.

whats the easy way to check that, looking at the sparkplug ? :thumbsup:

Read:

http://www.thumperta...699#post2881699

  • mdkcrf250r

Posted March 10, 2011 - 01:50 PM

#27

It is quite a dip. Most slip-on exhausts (it doesn't seem to matter which one very much) will add between 5-7 hp by actual Dyno readout on an '08, but only in the range between 4-6500 rpm. The CDI is worth about half that. I did see a dyno run on this change, but there were things about the way the test was run that made it less than totally scientific. But a ride on another bike did seem to bear out the results.


I'm interested in seeing graphs comparing the 06 and 08 cdi and the difference between the stock and aftermarket 08 full systems using both cdis.

  • grayracer513

Posted March 10, 2011 - 02:26 PM

#28

The only thing I have on hand is this slip-on from Two Brothers, which I think it fair to describe as not being a leader in high performance exhausts. Note the spread at 5000 RPM.

Attached Files



  • davidl9999

Posted March 10, 2011 - 03:13 PM

#29

The only thing I have on hand is this slip-on from Two Brothers, which I think it fair to describe as not being a leader in high performance exhausts. Note the spread at 5000 RPM.

No bias there, Gray.. :lol:
I like their pipes. Nice bling, nice sound (loud as F***!), woke up my 250F. Hated the headpipe drooping over the oil filter bolt so I had to remove the exhaust everytime I changed the oil... :smirk:
Still, great C.S. everytime I've dealt with them. :thumbsup:
PC Ti-4R on the 450 though... :busted:

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • dbehr624

Posted March 10, 2011 - 04:36 PM

#30

So I am looking at the 07 CDI for my 06 since I found a good deal on a brand new OEM one... I assume I have to adjust the cam timing?

  • grayracer513

Posted March 10, 2011 - 10:03 PM

#31

You cannot effectively adjust the cam timing on a YZF to any practical degree. The difference in the '06 and '07 lobe centers is only about 4 degrees. Each tooth on the cam sprocket would change the timing 22 degrees.

  • dbehr624

Posted March 10, 2011 - 11:20 PM

#32

Once again gray, you have answered everything I needed. Thanks for everyones input.

  • grayracer513

Posted March 11, 2011 - 08:23 AM

#33

Hot cams and some others do make cams for the intake, and maybe the exhaust that have sprockets that can be moved on the cam to alter timing in realistic increments. The trouble with the exhaust is that retiming that cam changes the timing of the decompression event, so the allowable movement has to be restricted.

  • humpness

Posted March 11, 2011 - 08:48 AM

#34

has any one used the 06 cdi in a 07? Im wondering if anyone has how it differed. I am told the you may loose top end but gain low. any first hand experience

  • dbehr624

Posted March 13, 2011 - 08:50 PM

#35

One more question for you gray. Do you know much different the degree of the lobe centers are between the 06 and 04? I found an 04 CDI and an 07 for sale, and am just trying to decide between them.

  • davidl9999

Posted March 13, 2011 - 08:52 PM

#36

Not Gray, but pretty certain that the '04 is a better choice for your '06 than the '07 CDI.

  • dbehr624

Posted March 13, 2011 - 09:22 PM

#37

That is my understanding also, I just want to make sure that I dont have to adjust any cam timing if I do elect to go with the 04 CDI

  • grayracer513

Posted March 14, 2011 - 06:17 AM

#38

You don't need to tweak the cam timing to use any CDI on any other YZF. The cam timing is just one of the elements of engine tune that varies between the different years, and the cam timing and ignition maps compliment one another. It is not, for example, necessary to change either cam in an '08 to utilize an '06 CDI in it and get some improvement in mid range power.

To directly address your question, although I don't have the specific numbers, the '04 cam set has slightly wider lobe centers than the '06, just as the '06 is slightly wider than the '07. While I have never tried it or spoken with anyone who swapped an '04 CDI onto an '06, my guess is that you would increase low and mid range somewhat, and have an unknown effect on top end power. The '04 was strong on the bottom to a fault, and was criticized as being difficult to ride, but they were kind of fun in their way, too.

The '07 CDI would likely either improve the top or have no effect on it, but would probably slightly reduce the low end power.





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