Feels sluggish

8 replies to this topic
  • Spiz

Posted September 14, 2014 - 05:21 AM


hey guys,

so just bought a 2009 yz480f has the athena big bore kit, havent taken it out yet , i noticed when i grabbed it, that it has a 45 rear tooth took it for a quik lap around the block and it feels real sluggish not snappy at all doesnt really feel quick at all to be honest would this be due to the rear sprocket being that size pretty sure front is 14tooth , what would be my best option i defenetly want a change of how it is. want it to really pull me back have sum good pull on it and to pop up easy pops up really far into the revs.

what would be my best options for sizes i was thinking 49 rear or 50, on my crf450 i had was 49rear and it was perfect real snappy and felt like a jet down low and up top just kept pulling.. but yamaha have different gearing true?

aswell it has a two brothers exhaust system its not as loud as i would like whats my options for a more louder exhaust change the muffler? My crf450 was so much more growler deeper really like the cracking of the 4 stroke sound

Also when I bought it he said the extra jetting makes the bike pop and fart heaps when it's revving down a lot of fuel going threw it due to the 480 bore kit? I didn't care when I got it but now it's annoying Is there a way to get rid of it safely or I need the richness for the bike to run good and not risk motor
damage not to sure about it all.

any info is greatly appreciated sorry for the noob questions
thanks guys

  • YzCas

Posted September 14, 2014 - 07:18 AM


I would go back to stock gearing. If the engine runs good that's the problem sounds like the previous owner had a funky set up on it.

  • Spiz

Posted September 14, 2014 - 07:29 AM


Yeah I'm hoping nothing is wrong but bike is in immac condition , I was thinking 13 front 50 rear? Whats most common set ups

  • grayracer513

Posted September 14, 2014 - 09:29 AM


The '08 and '09 models had two problems that contributed to a complaint of sluggish response/lack of low-mid power; the CDI map and the cute little "shorty" muffler.  The cure is almost any other exhaust system and the CDI unit from an '06.  ALternative CDI's that will also improve things are the '04, '03, or '07, in that order of preference.

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  • Spiz

Posted September 14, 2014 - 02:58 PM


How do I check which one I have just in case it's been changed

  • Spiz

Posted September 14, 2014 - 03:11 PM


where would be my best option to purchase the cdi from and cheapest i have from sydney australia.

  • grayracer513

Posted September 15, 2014 - 10:43 AM


How do I check which one I have just in case it's been changed


An '06 CDI would be stamped with "2S2-00"

  • Spiz

Posted September 15, 2014 - 08:15 PM


Does this cdi change really do all that much of a difference ? I haven't found to much about it ? Is it a common problem that effects everyone would it be a change you'd notice dramatically ??

  • grayracer513

Posted September 16, 2014 - 06:13 AM



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