High compression piston or cams?


17 replies to this topic
  • ectm3

Posted January 14, 2011 - 08:02 AM

#1

I ride a yz450f 2009 and would like more snap across the power band.Should i change out the cams or go for a high compression piston?
I guess i should have mensioned that my bike already has a fmf ti 4.1 full mega bomb system and a jd ignition(cdi). I also change out my sprocket depending riding conditions(track,ice racing or just trail riding)My previous bike was a 86 cr 500,Im looking for more ZAP!(without going big bore).Just not sure.....

Edited by ectm3, January 15, 2011 - 12:05 PM.
Add info


  • KTM 2 SMOKER

Posted January 14, 2011 - 08:04 AM

#2

a cam and a good re-map of the fi system will definatly help you out.

  • FiremanKay

Posted January 14, 2011 - 08:21 AM

#3

a cam and a good re-map of the fi system will definatly help you out.


hmmm dont know if you read his post right.

Anyhow, from what a lot of guys are saying, swapping out the stock pipe will bring the bike to life. I plan to do this myself this year, if I feel it needs more I will go from there.

  • Gunner354

Posted January 14, 2011 - 08:49 AM

#4

I ride a yz450f 2009 and would like more snap across the power band.Should i change out the cams or go for a high compression piston?


A Dr D pipe made a huge difference on my 09. Still was not enough, so I installed an 06 cdi I bought off eBay. The motor is perfect for my riding style.

  • grayracer513

Posted January 14, 2011 - 09:39 AM

#5

A pipe (almost any pipe) or a mod to the stock muffler and an '06 CDI are what you need.

  • KTM 2 SMOKER

Posted January 14, 2011 - 10:12 AM

#6

hmmm dont know if you read his post right.

Anyhow, from what a lot of guys are saying, swapping out the stock pipe will bring the bike to life. I plan to do this myself this year, if I feel it needs more I will go from there.


what didnt i read right? isnt the 09 fuel injected? a good grind on a set of cams and good map on the fi system should definatly give you some power...whats wrong about that?

  • rmcr250r

Posted January 14, 2011 - 10:19 AM

#7

what didnt i read right? isnt the 09 fuel injected?


Nope...

  • ectm3

Posted January 18, 2011 - 11:10 AM

#8

hmmm dont know if you read his post right.

Anyhow, from what a lot of guys are saying, swapping out the stock pipe will bring the bike to life. I plan to do this myself this year, if I feel it needs more I will go from there.


wondering about the cams or piston,not the exhaust system........

  • ectm3

Posted January 18, 2011 - 11:13 AM

#9

A pipe (almost any pipe) or a mod to the stock muffler and an '06 CDI are what you need.


more so the cams or piston,already have a jd ignition and fmf 4.1 full system.

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  • KTM 2 SMOKER

Posted January 19, 2011 - 09:13 PM

#10

if im correct a high comp piston will help you out down low but wont due much on the top end, i think cams and a good jet kit are what you need man.

  • FiremanKay

Posted January 19, 2011 - 09:45 PM

#11

Not trying to be a downer, but you are coming of a CR500. There is no way you are going to get that feel from this bike. Old school 500s are beasts, so it is understandable for you to feel the way you do about the 4 stroke. I really think you have done the most cost effective mods as mentioned thought the forum. You cant turn a Apple to a Orange, if you know what I mean. I know what your asking but I just dont think, for my reading on this forum, that it will lead you to the results you are hoping for. The YZ is know for its smooth linear power, there has been a few KX guys looking at how to get the Kawi feel from the YZ. They have been unsuccessful to my knowledge, a lot of money goes into making a motor the way it is. So it would make sense that it would take a bit to change it completely. Anyhow, I know this did not answer your question directly but I just wanted to share my little info until someone else steps in. Hate to see you spend money and not be happy with the results. Sorta like the race fuel discussion .

  • beezer

Posted January 20, 2011 - 01:12 PM

#12

You can make a YZ450 so fast no mortal man can hang on to it.

  • ttr250dude

Posted January 20, 2011 - 02:40 PM

#13

You can make a YZ450 so fast no mortal man can hang on to it.


X2. It all depends how deep your pockets are.

  • JDLowrance

Posted January 20, 2011 - 05:25 PM

#14

A simple bump in compression and a set of cams to move the power up in the RPM range will wake this bike up like you wouldn't believe and it's not that expensive.

The cams will take away a little power from the bottom or mid and move it to the top (depending on the grind). For example the Hotcams will take 2-3 from the mid and add it on top. Then you bump the compression to 13.5:1 which will get the 3 back on the bottom and add a couple more to the top which will result in an overall gain of 5hp or so on top without any losses to the bottom.

Simple hot rodding.

You will feel a dramatic improvement in acceleration. You may need to run a 50/50 mix of pump and race fuel to prevent detonation although others swear it's not necessary. I've got the parts sitting on my bench waiting to go into my 08 (soon).

John

  • ectm3

Posted January 21, 2011 - 06:29 PM

#15

Nice,thats exactly what im looking for.I wasnt sure which way to go,now the direction is clear.Thanks.

  • JDLowrance

Posted January 22, 2011 - 11:41 AM

#16

No worries. Let us know how you make out.

John

  • Nickm27

Posted January 31, 2011 - 09:37 AM

#17

I just ordered the stage 2 hotcams, with new wiseco cam chain for my 07 450... Im wanting to do like the guy earlier said... make it soo fast i cant hang on to it!!!!!! hahahhaha:banana::thumbsup:

  • DMauro

Posted January 31, 2011 - 09:50 AM

#18

stage 2 losses of bottom to get more rev, the original post would be better of with stage 1 more mid and top than stock. after hot cams you can go even more agressive higher lift but then you will need springs and buckets. a piston will not give you that much. if you need a new piston thats fine but to go to high you will need race gas and if you do that your better off with u-4.2 or same that will give you more power.





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