Author Topic: 4-Valve Head Kits Released.  (Read 2239 times)

0 Members and 2 Guests are viewing this topic.

derottone

  • Grand Gearhead
  • *****
  • Posts: 2,558
  • Karma: 0
Reply #45 on: November 20, 2022, 06:56:48 pm
From the first pic it looks like they've made a new injector body to go with this. I assume the throttle body is stock.
"Proles and Animals are free"
"Ignorance is strength"


ace.cafe

  • Grand Gearhead
  • *****
  • Posts: 14,438
  • Karma: 1
  • World leaders in performance/racing Bullets
Reply #46 on: November 20, 2022, 07:33:02 pm
I was informed that the port measures 45mm x 26mm. So if my brain is still working, the port area is comprised of 2 x 13mm radius semicircles, effectively a single 13mm radius circle, plus a rectangular area which is 26mm x (45-26) = 25 x 19mm. My calculations came to a cross-sectional area of 1030sq mm, roughly halfway between that of a 36mm carburettor and a 37mm (Keihin FCR) carburettor, though most CGT owners are probably thinking in terms of FI throttle bodies, I would suspect.

Any help?

A.
Yes, helpful.
Thanks!
In other words it needs a bigger than stock throttle body, or velocity takes a big dump at the transition.

It's a tough call to make as a designer.
Do I port it big for maximum power and rpm, or do I make it work best with the stock throttle body on the street?
Interesting choice.

In the interests of full disclosure, I ported our Ace billet 2-valve heads to work best with the stock TB on the street, and left the bigger porting to the purchaser if he wants it bigger. I figured most owners would use the stock ancillaries.
Derottone ported his up to 36mm at my last hearing.
Home of the Fireball 535 !


derottone

  • Grand Gearhead
  • *****
  • Posts: 2,558
  • Karma: 0
Reply #47 on: November 20, 2022, 08:21:19 pm
You would probably want to go with the 36-37 mm carb with this arrangement, which may direct you towards to the 6.5 - 7.5 k revs if that valve train is capable of it.
"Proles and Animals are free"
"Ignorance is strength"


Adrian II

  • Grand Gearhead
  • *****
  • Posts: 3,568
  • Karma: 1
  • Sharing my ignorance with anyone who needs it
Reply #48 on: November 21, 2022, 04:19:13 am
Using a carb will need a custom manifold for a smooth transition, of course. Could be an interesting morning's work with a block of alloy.

A.
Grumpy Brit still seeking 500 AVL Bullet perfection! Will let you know if I get anywhere near...


derottone

  • Grand Gearhead
  • *****
  • Posts: 2,558
  • Karma: 0
Reply #49 on: November 21, 2022, 08:36:58 am
Using a carb will need a custom manifold for a smooth transition, of course. Could be an interesting morning's work with a block of alloy.

A.

Should be a good rehab work for the covid patients.  ;)
"Proles and Animals are free"
"Ignorance is strength"


KD5ITM

  • Financial problem solver
  • Grand Gearhead
  • *****
  • Posts: 1,078
  • Karma: 0
Reply #50 on: December 04, 2022, 05:24:45 pm
Staying within the same topic but throwing out a bit of a different question...

All I've done to my 2014 GT is the stage 1 performance kit, the Power Commander 5, free flow header pipe and Muffler along with the K&N Filter. The RPM range that my bike spins nearly 100% of its time is between 3:00 and 4,000 RPMs. And when I'm on the highway, I'm very comfortable keeping it right around 62 to 64 mph which keeps it a bit under 4,000 RPMs.

I would love to boost the performance of my bike but not necessarily looking for maximum top-end speed. Where I would benefit from more power and torque would be on the freeway at 62 mph riding into a block 15 to 20 mph headwind where you have the throttle cracked 80% and the bike is struggling to keep speed or at the same time, trying to pass a semi truck without the bike struggling.

What would be the most beneficial modification to boost the mid-range torque and Power?
2014 Continental GT - red
1979 Hurst/Olds W-30
1964 Volvo Sport PV554 B18
1961 Willys Jeep Utility Wagon


Adrian II

  • Grand Gearhead
  • *****
  • Posts: 3,568
  • Karma: 1
  • Sharing my ignorance with anyone who needs it
Reply #51 on: December 04, 2022, 10:01:09 pm
612 kit?

A.
Grumpy Brit still seeking 500 AVL Bullet perfection! Will let you know if I get anywhere near...


gizzo

  • Grand Gearhead
  • *****
  • Posts: 4,990
  • Karma: 0
  • Ding a ding dang my dangalong linglong
Reply #52 on: December 04, 2022, 11:24:36 pm
Supercharger
simon from south Australia
Continental GT
Pantah
DR250
DRZ400SM
SL125


KD5ITM

  • Financial problem solver
  • Grand Gearhead
  • *****
  • Posts: 1,078
  • Karma: 0
Reply #53 on: December 05, 2022, 12:11:15 am
612 kit?

A.

I've heard more than once on here that the 612 Big Bore Kit causes the bike to run out of breath at higher rpm. Good for low-end torque in hilly terrain or if using a sidecar.
2014 Continental GT - red
1979 Hurst/Olds W-30
1964 Volvo Sport PV554 B18
1961 Willys Jeep Utility Wagon


KD5ITM

  • Financial problem solver
  • Grand Gearhead
  • *****
  • Posts: 1,078
  • Karma: 0
Reply #54 on: December 05, 2022, 12:13:07 am
612 kit?

A.
I've heard more than once on here that the 612 Big Bore Kit causes the bike to run out of breath at higher rpm. Good for low-end torque in hilly terrain or if using a sidecar.
2014 Continental GT - red
1979 Hurst/Olds W-30
1964 Volvo Sport PV554 B18
1961 Willys Jeep Utility Wagon


ace.cafe

  • Grand Gearhead
  • *****
  • Posts: 14,438
  • Karma: 1
  • World leaders in performance/racing Bullets
Reply #55 on: December 05, 2022, 12:17:40 am
Staying within the same topic but throwing out a bit of a different question...

All I've done to my 2014 GT is the stage 1 performance kit, the Power Commander 5, free flow header pipe and Muffler along with the K&N Filter. The RPM range that my bike spins nearly 100% of its time is between 3:00 and 4,000 RPMs. And when I'm on the highway, I'm very comfortable keeping it right around 62 to 64 mph which keeps it a bit under 4,000 RPMs.

I would love to boost the performance of my bike but not necessarily looking for maximum top-end speed. Where I would benefit from more power and torque would be on the freeway at 62 mph riding into a block 15 to 20 mph headwind where you have the throttle cracked 80% and the bike is struggling to keep speed or at the same time, trying to pass a semi truck without the bike struggling.

What would be the most beneficial modification to boost the mid-range torque and Power?
Increased compression with squish mod, as I mentioned on the other thread.
It will help at any/all rpms.


As for the 612, I have never been a fan. Just my opinion.
Home of the Fireball 535 !


gizzo

  • Grand Gearhead
  • *****
  • Posts: 4,990
  • Karma: 0
  • Ding a ding dang my dangalong linglong
Reply #56 on: December 05, 2022, 02:38:21 am
I've heard more than once on here that the 612 Big Bore Kit causes the bike to run out of breath at higher rpm. Good for low-end torque in hilly terrain or if using a sidecar.
You've said yourself that you're not operating in the higher rev range so what's the problem?
simon from south Australia
Continental GT
Pantah
DR250
DRZ400SM
SL125


KD5ITM

  • Financial problem solver
  • Grand Gearhead
  • *****
  • Posts: 1,078
  • Karma: 0
Reply #57 on: Yesterday at 03:50:14 pm
As for the 612, I have never been a fan. Just my opinion.

I believe it was you Ace that said a couple of years ago that you felt that the 612 kit caused the bike to “run out of breath at higher RPM’s”, but did allow for more torque at lower RPM’s “for side car use or in hilly terrain”. 

Whats your thoughts on the reason for it “running out of breath” at higher RPM’s. 
2014 Continental GT - red
1979 Hurst/Olds W-30
1964 Volvo Sport PV554 B18
1961 Willys Jeep Utility Wagon


ace.cafe

  • Grand Gearhead
  • *****
  • Posts: 14,438
  • Karma: 1
  • World leaders in performance/racing Bullets
Reply #58 on: Yesterday at 05:13:01 pm
I believe it was you Ace that said a couple of years ago that you felt that the 612 kit caused the bike to “run out of breath at higher RPM’s”, but did allow for more torque at lower RPM’s “for side car use or in hilly terrain”. 

Whats your thoughts on the reason for it “running out of breath” at higher RPM’s.
Because the head isn't ported to handle the extra displacement, and the piston speeds from the longer stroke cause it to choke the intake earlier.
It's not insurmountable, but it needs somebody who knows what he's doing.

In addition, the bottom end parts are not the strongest, and the longer stroke will limit the reliability in higher rpm ranges.
« Last Edit: Yesterday at 05:15:47 pm by ace.cafe »
Home of the Fireball 535 !