big difference btwn 02 and 05 CR 125's

B

bburnette

Member
Mar 13, 2007
8
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i had an 02 cr125 and kept it stock except for a vertex piston, v-force and fmf fatty pipe, then i got an 05 and had it bored to a 139 by Erik, then added v-force and fmf fatty pipe. why is it that my 02 spanks the 05? it is sooo much more potent off bottom and pulls to the moon in mid, to where the 05 139--ehhh--its ok. it seems to be extremely linear through the whole power band and doesnt really pull my arms out of their sockets like the 02 does. :think:
 
B

bburnette

Member
Mar 13, 2007
8
0
i agree with u 2-stroke. i was hoping i could get the 05 to pull like the 02 and it be fresher and an even stronger engine. i am really hoping for some insight from someone about what may be going on with that 02 and why it is so strong. i mean..i cant explain how strong it is, it must be ridden (i apologize for any gloating there) but when ever i tell anyone, they really dont believe me until they have ridden it. im not knocking Erics work by any means. its just that that 02 is a total beast.

extreme--i have not started to mess with jetting on the 05 yet. and you may be on to something because it lugs in the corners and if i go into breaking bumps really hard it will cut off and as soon as i let out the clutch it kicks back on. im thinking i may be a tad bit rich, but the spark plug looks ok. i will check that this weekend.
 
kawicam250

kawicam250

I bleed green!
Member
Aug 7, 2006
1,162
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he is on to something, and he beat me to it ;) . if the jetting is still stock( factory setting), then it will be rich. there are a lot of variables in power output, but once you get the '05 dialed in, it should be much more powerful. from what ive heard/read, Honda made big changes after the disappointment of the earlier models, their supposed to be a lot faster. start with the jetting, jetting can completely change your power output around without throwing the $$ on the table :cool: .
 
B

bburnette

Member
Mar 13, 2007
8
0


yeah. im really hoping that is what the issue is. the 02 is a light switch compared to the 05. im reading up on jetting now.
 
K

kawikiller

Member
Mar 2, 2007
52
0
yes everything i have heard and read said they made big changes in 05 and the cr125 placed 2nd place just barely losing to the yz125 in dirtriders 125 shootout
 
S

snb73

Member
Nov 30, 2003
770
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I was under the impression that Eric did 144 big bores? In any case, Eric's big bore will smooth out the power making it more usable, you will not feel the "light Switch" type power of your 02. Contact Eric with your issues, his product support is excellent.

Do not confuse "abrupt power" and "having your arms pulled out of their sockets" as a gauge of "power". Have you riden these bikes side by side on a track? Checked lap times? Have a buddy ride the 02, and you ride the 05 for lap times. Then switch bikes and compare laps times. I think you will find the smooth bike is easier and "faster" to ride.

Proper jetting will definately wake any bike up.

Make sure you have fresh gas with a good quality premix oil. I would suggest a ratio of 32:1

Don't forget a fresh sparkplug too.


Here are a few links for reading:

http://www.keihin-us.com/tune.htm

http://www.ngksparkplugs.com/techin...1000&country=US

http://justkdx.dirtrider.net/carbtuning.html

http://www.powroll.com/tech_specs_jetting101.htm

http://www.duncanracing.com/techfaq...n-jetting.phtml

http://www.keihin-us.com/am/tuning/

http://www.dansmc.com/spark_plugs/s...gs_catalog.html

http://www.ngksparkplugs.com/techin...1000&country=US

http://dirtrider.net/forums3/showthread.php?t=42618

Good luck, Steve.
 
B

bburnette

Member
Mar 13, 2007
8
0
thanks steve! unfortunately i sold the 02 so im no longer able to get someone to ride it with me to compare. i will try the lap times next chance i get. i sold it to a family friend so sometimes we are at the same track.
 
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