Horsepower Gain for an 05 450R with a CP 12:1 piston in place of stock piston?

[yfz450admirer]

What gains will a 12:1 CP piston give over a stock 10.5:1 piston?

[bloodmoney23]

well i just did a 11.5:1 on my 05 and it was nothing of a difference untill i put in HRC cam. so in other words you aint gonna get much gain unless you run race fuel and that should start at 12.5:1 i believe on the 05's or it may be 12:1. I dont know man but i didnt notice a difference with just a hc piston.

[400exrider707]

Originally posted by bloodmoney23
well i just did a 11.5:1 on my 05 and it was nothing of a difference untill i put in HRC cam. so in other words you aint gonna get much gain unless you run race fuel and that should start at 12.5:1 i believe on the 05's or it may be 12:1. I dont know man but i didnt notice a difference with just a hc piston.


You wont gain much unless you run race fuel because....?:confused:



Here's a very good tech read about compression ratios courtesy of chad502EX http://www.exriders.com/vbb/showthread.php?s=&threadid=294703&highlight=High+Compression

[yfz450admirer]

I have a hot cam stage II, 39 fcr carb, and pulse charger exhaust.

[bloodmoney23]

go with the 12.5:1 piston and run cam2 race fuel and you will be good. you wont get a huge gain but the only other HP gain on these atv's is a bigbore kit and get your head completely redone. and unless your racing pro i wouldnt worry about that stuff yet.

[pro-rider46]

well if he is going to go to run race fuel he might as well go as far as he can, contact chad502ex and he has a piston that is 15 to 1. truely impressive. i hope soon that i can get one.

[400exrider707]

Originally posted by bloodmoney23
go with the 12.5:1 piston and run cam2 race fuel and you will be good. you wont get a huge gain but the only other HP gain on these atv's is a bigbore kit and get your head completely redone. and unless your racing pro i wouldnt worry about that stuff yet.


:confused: Where do you get your information?

[hendershot106]

Originally posted by bloodmoney23
go with the 12.5:1 piston and run cam2 race fuel and you will be good. you wont get a huge gain but the only other HP gain on these atv's is a bigbore kit and get your head completely redone. and unless your racing pro i wouldnt worry about that stuff yet.

eehh helloooo????? what about porting and polishing??? bigger carbs?????? better exhaust systems???? i agree with 400ex rider707 :confused: :confused: :confused:

[bloodmoney23]

ok, porting and polishing come with head being redone, and my statement was based on that he already has exhaust, filter kit and so forth. If he is doing a HC piston im hoping he already has the normal boltons already done. And sorry but i wasnt really awake nor did i have the time to fully explain. All i know is with a HC piston and race fuel u will get a small gain but not much. And headwork is where you get most of your hp out of these engines.

[Chino886]

All are pieces to the puzzle!

High flowing head with a super restrictive intake won't do much good!

Big carb with non-flowing head won't do much good either!

Good cam, high compression, good flowing head, good flowing exhaust, good intake, big carb = haulin ***

[400exrider707]

Originally posted by Chino886
All are pieces to the puzzle!



Agreed. There are many small things that really add up.

[HondaBoy450RToy]

i love my 06 450R to death and i think if your hitting nice trails mountain flat and tight trails this is the quad to do it with, and wheelies are easy with the TRX! the balance point is just as amazing as a 400, plus you dont have to worry about rings going bad because your idling in a trail. the 450 has so much power potential but if your trail riding all you need to do is free up the intake restrictions and exhaust restrictions. HRC kit is fun too


but i do have a question for you professionals.

i have;

K&N Filter
new airbox
and white brothers pro alum. kit
i dropped a tooth in the rear and love it to death, but would dropping a tooth in the front be better? or maybe do both? i dont know too much about the changes in gearing for sprockets and i would love to know more about it and what would help me, im looking for a little less power because i know all i have to do is buy an HRC kit to regain it if i feel neccessary, plus my trails are extremely manicured flat service roads for black dirt fields in NY. i just want a little more top end and a little better cruising RPMS in the wide open trails.

will it help what im trying to achieve?
will it take too much power from me?
i didnt feel much in the rear, but it does wheelie alot easier with the 1 dropped tooth in the rear!

[bloodmoney23]

less power? well ok, go up in tooth number for less power more topend and go down for more bottom end and torque. Just think of it like a moutain bike. smallest sprocket on front and rear you pedal 20 mph and go 2 mph but can make it up the hill which means smaller in front and rear equals more rpms, more torque and less speed. bigger on rear and front would be less engine rpm, less torque and more speed but you get to top speed slower.

[HondaBoy450RToy]

wow i was really off, for some reason my physics are thinking differently, i think they are off. thanks for the info and i think im just going to get the HRC kit and some extras for the trails. i havent ever hit a track with it but i think its more of a trail quad anyways. is anyone selling any extras?

[d3ktrix]

Originally posted by bloodmoney23
less power? well ok, go up in tooth number for less power more topend and go down for more bottom end and torque. Just think of it like a moutain bike. smallest sprocket on front and rear you pedal 20 mph and go 2 mph but can make it up the hill which means smaller in front and rear equals more rpms, more torque and less speed. bigger on rear and front would be less engine rpm, less torque and more speed but you get to top speed slower.

Huh? Thats really confusing, not sure what you meant but...

Front Sprocket:
Reducing teeth = Increased low end
Increasing teeth = Increased top end

Rear Sproket
Reducing teeth = Increased top end
Increasing teeth = Increased low end

They work opposite of each other.

Also changing 1 tooth on the front sprocket is almost equal to changing 3 teeth on the rear sprocket.

[400exrider707]

Originally posted by d3ktrix
Huh? Thats really confusing, not sure what you meant but...

Front Sprocket:
Reducing teeth = Increased low end
Increasing teeth = Increased top end

Rear Sproket
Reducing teeth = Increased top end
Increasing teeth = Increased low end

They work opposite of each other.

Also changing 1 tooth on the front sprocket is almost equal to changing 3 teeth on the rear sprocket.

Yes this post makes a LOT more sense.

[bloodmoney23]

Originally posted by d3ktrix
Huh? Thats really confusing, not sure what you meant but...

Front Sprocket:
Reducing teeth = Increased low end
Increasing teeth = Increased top end

Rear Sproket
Reducing teeth = Increased top end
Increasing teeth = Increased low end

They work opposite of each other.

Also changing 1 tooth on the front sprocket is almost equal to changing 3 teeth on the rear sprocket.

ummm....i meant the same thing as you but didnt explain it as short and precise. sorry oh mighty gods

[660r2a400ex]

going down on the front is for bottom end, going down on the rear is oppisite.

[d3ktrix]

Originally posted by bloodmoney23
ummm....i meant the same thing as you but didnt explain it as short and precise. sorry oh mighty gods

lol no hard feelings man I just wasn't sure what you meant.

[bloodmoney23]

Originally posted by d3ktrix
lol no hard feelings man I just wasn't sure what you meant.

no its just this 400exrider707 has something to say about everything i say and it is starting to get on my nerves...

[HondaBoy450RToy]

haha that makes alot more sense no offense but that sounds good thanks for the input on the sprockets

[d3ktrix]

glad to help

[400exrider707]

Originally posted by bloodmoney23
no its just this 400exrider707 has something to say about everything i say and it is starting to get on my nerves...

If you weren't posting wrong information we wouldn't have a problem.



Originally posted by bloodmoney23
less power? well ok, go up in tooth number for less power more topend and go down for more bottom end and torque.

Go up in tooth count on which sprocket? If you go up in tooth count on the rear it will make the top speed slower and have more acceleration. If you go up in tooth count on the front it does the exact opposite.



Originally posted by bloodmoney23
Just think of it like a moutain bike. smallest sprocket on front and rear...

If you put smaller on front and rear, they are effectively cancelling each other out...

Smaller on rear = more speed, less acceleration
Smaller on front = less speed, more accleration

I kind of understand what you were trying to say, but that is only because I already understand the concept. Someone who may not understand it, would either be more confused, or get the concept of it wrong because of your post. I have no problems with you helping people or posting information, but if you're going to do it, please take the time to explain it better, and post correct information. If you dont know, just ask, someone will know, there are a lot of smart people on these boards. Dont forget you are posting in a public message board so dont take it personal when you get some criticism.

[bloodmoney23]

Originally posted by 400exrider707
If you weren't posting wrong information we wouldn't have a problem.




Go up in tooth count on which sprocket? If you go up in tooth count on the rear it will make the top speed slower and have more acceleration. If you go up in tooth count on the front it does the exact opposite.




If you put smaller on front and rear, they are effectively cancelling each other out...

Smaller on rear = more speed, less acceleration
Smaller on front = less speed, more accleration

I kind of understand what you were trying to say, but that is only because I already understand the concept. Someone who may not understand it, would either be more confused, or get the concept of it wrong because of your post. I have no problems with you helping people or posting information, but if you're going to do it, please take the time to explain it better, and post correct information. If you dont know, just ask, someone will know, there are a lot of smart people on these boards. Dont forget you are posting in a public message board so dont take it personal when you get some criticism.

I posted the same thing as you except i wasnt as short and precise. To do it, I know what im doing and gaurentee a better job done then you. But to explain it......well ill leave that area up to you. Sorry after 6 years in military, 2 of them in iraq and 1 in afghanistan your sense of explanation and cool temper kinda go out the window.

[400exrider707]

Originally posted by bloodmoney23
I posted the same thing as you except i wasnt as short and precise. To do it, I know what im doing and gaurentee a better job done then you. But to explain it......well ill leave that area up to you. Sorry after 6 years in military, 2 of them in iraq and 1 in afghanistan your sense of explanation and cool temper kinda go out the window.

No it wasn't so much the clarity of the post, it was the incorrect information. It's ok it's been explained already and none of it has to do with the original thread topic so we'll let it rest.