How many HPs gain can i expect from a coolhead?

[Willybanshee]

Hi! i just ordered a Noss coolhead with 21cc domes... just wondering how many HPs im gonna gain!? my mods for now are  T5 pipes, KN filter with airbox no snorkel, timing plate +4... Just premium 90 octane pump fuel (highest octane you can find here in AK) My elevation is around 500 feet and temp is around 60-70s... My current jetting is 300 mains, stock needles and  stock 25 pilots but im gonna switch to 27.5... Shee is working perfect right now! Thanks! and any additional info/advice is welcome...

 

PS: still working on my english...

[Young Guns Racing]

You may have to rejet ur carbs for the new head. Im not 100% sure u will or not just giving u a heads up. And btw ive heard of good.cool heads netting an easy 2 hp

[bansheeryder21]

Cool heads don't give to much HP without ported cylinders. I did pretty much every bolt imaginable before I got my motor ported by HJR and never noticed any big changes. Once Kevin did a dune port it was a completely different machine. If I were you, I would spend the $300-400 and get a nice port job done by Kevin at HerrJugsRacing. You will notice a substantial gain in power, especially if you use 19cc domes and go to race or Avgas. Give him a call anytime, he is very friendly to talk to and will give you the advice your looking for.

Www.herrjugsracing.com

(760) 703-1836

[Willybanshee]

I know the coolhead its not gonna be a big gain but at least 1 or 2 hp is something!... Definately my next mod its gonna be porting the cylinders! I got already an additional pair to send them and also get a wisecos in that same trip!Thanks

[Chris327]

21cc dome is just a pump gas dome... you wont notice that much of a gain at all. like everyone else has already said, get a nasty port job done then some velcro cause you will need to strap your ass to the seat 

[milto29]

Cool heads don't give to much HP without ported cylinders. I did pretty much every bolt imaginable before I got my motor ported by HJR and never noticed any big changes. Once Kevin did a dune port it was a completely different machine. If I were you, I would spend the $300-400 and get a nice port job done by Kevin at HerrJugsRacing. You will notice a substantial gain in power, especially if you use 19cc domes and go to race or Avgas. Give him a call anytime, he is very friendly to talk to and will give you the advice your looking for.

Www.herrjugsracing.com

(760) 703-1836

 

 

I agree with you 100%. My old setup had it all (Bolt On). Pro design cool head with 20cc domes , SB CPI pipes , Pods , +4 time , 15 tooth sprocket and when she finally blew since the damage was tremendous. We had to bore it out to 66.25.

 

Now with my new setup on 64 ported cylinders , 4mm hot rod crank and stock head. It's a totally different bike. And yes once it's ported correctly hold on tight.

 

 

 

Sent from my HTC One

 

[bansheeryder21]

I agree you with 100%. My old setup had it all (Bolt On). Pro design cool head with 20cc domes , SB CPI pipes , Pods , +4 time , 15 tooth sprocket and when she finally blew since the damage was tremendous. We had to bore it out to 66.25.

 

Now with my new setup on 64 ported cylinders , 4mm hot rod crank and stock head. It's a totally different bike. And yes once it's ported correctly hold on tight.

 

 

 

Sent from my HTC One

X2

[possum]

now wait till you actually ride something fast. you will need more the velcro to keep your hands on the grips.. haha

[Stonytony]

An aftermarket head gives you 1 or 2 hp. The point of a head with changeable domes is to gain compression back after changing port timing.

[Stonytony]

You change your port timing by doin a port job and you loose compression. Then you have to get that compression back. To achieve that you can mill a head (waste of time IMO because the dome is wrong) or aftermarket with changeable domes so you get the correct compression. That's why you add an aftermarket head. Stock port timing with stock head 110-115psi per cylinder. Stock port timing aftermarket head and now 130 psi 1-2hp increase but you gotta run 93 octane or even safer 110 because you'll burn hotter and you'll need a fuel that burns colder to offset the change.

[sheerider11]

You change your port timing by doin a port job and you loose compression. Then you have to get that compression back. To achieve that you can mill a head (waste of time IMO because the dome is wrong) or aftermarket with changeable domes so you get the correct compression. That's why you add an aftermarket head. Stock port timing with stock head 110-115psi per cylinder. Stock port timing aftermarket head and now 130 psi 1-2hp increase but you gotta run 93 octane or even safer 110 because you'll burn hotter and you'll need a fuel that burns colder to offset the change.

Are you fucking stoned?

[joey83]

You change your port timing by doin a port job and you loose compression. Then you have to get that compression back. To achieve that you can mill a head (waste of time IMO because the dome is wrong) or aftermarket with changeable domes so you get the correct compression. That's why you add an aftermarket head. Stock port timing with stock head 110-115psi per cylinder. Stock port timing aftermarket head and now 130 psi 1-2hp increase but you gotta run 93 octane or even safer 110 because you'll burn hotter and you'll need a fuel that burns colder to offset the change.

 

Sounds legit..

[Willybanshee]

Ok... Im not gonna put my coolhead until get first my jugs ported, ill send them this week. Now, the question is: how many compression i should expect when i get a dune/play port and 21cc domes? Thanks!

[Willybanshee]

It is gonna still safe for a not welded stock crank?

[Willybanshee]

Damn! I was expecting 145-150 with the 21s without the port job but i heard the port job also raise the compression too. I read until 160 stock not welded crank still safe...