[High On Octane]

Finally, the delivery of the Big Head was finalized today, and it was signed for at Mondello's.
So, I will check up on it tomorrow.

Also, the "fixings" kit for the Big Head from Hitchcock has already arrived without any issues with customs.

Ah man, let's not get started on customs.  I have an order in transit right now.......   

Awesome that you finally got the head tho!   

[ace.cafe]

Discussion with the owner today.

Due to some issues on his end, he was not able to take advantage of the BW piston construction run, so the decision was made to use the regular Hemi chamber, and a high compression piston to suit a methanol fuel. Some squish can be employed on the hemi piston, and I think he is going to secure a piston maker to do it, and we will provide a mold casting of the combustion chamber for the piston maker to design the crown. In any event, we won't be having to modify the combustion chamber, and it will remain a Hemi.

Valves will the stainless steel of a similar size to what BW is using in his head.

Port will be similar to BW's port size, but will be a little different because this head has a small port in it, so that gives us a little more flexibility in shaping this port. This port may end up being a little bit more "ideal" in shape, because of this.

Cams will be Hitchcock race cams, with .420" lift, so the lift height at the valve will be about the same as the BW head. But the duration and timing will be shorter. Probably, the maximum rpm range will be somewhat lower than BW's bike.

We will have more updates as some of these things get more firmed up. However, we can now get started on the head, since the main things which we needed to know are now decided.

 

[ace.cafe]

Racing Big Head Hi-Port Hi-Lift Roller Rocker head work completed!

Picked it up tonight, and will be shipping tomorrow. I will take some pics in the morning. Looks great!

Flow test included, and I will post numbers in the morning with the pics.
I can say from memory that the peak flow at .600" lift is about 265 cfm, which has the potential in full racing tune to give 67.84 hp at the crank. Most builds do not reach max potential, but it has a reasonable potential to match(or beat) any of the top Manx or G50 builds in the world out there. If he gets it all sorted and tuned to best power by race time, it could possibly win the 500cc single race.

Plans are to run this bike at the Phillip Island Classic Motorcycle Races in January. That's about the biggest classic race event in the Southern Hemisphere. Sort of like the Isle of Man for the Aussies.
Pretty cool!
 

[Mr.Mazza]

Cant wait to see Guy flogging the bike at Philip Island, last week he pulled the engine outta the frame, a new frame I think as the old one is just too old.
Hopefully he can pass the guidence from you guys into my road going Enfield, I'm looking at near same Hp as his old bike but street friendly.

[motorman2whel]

That's Outstanding Ace ! , Love to see a RE kickin some butt and screamin down the straights to the WIN.  . Someone has got to take some vids of it in action, with sound.

[High On Octane]

Nice work Ace!  65bhp out of a 500 single is pretty damn tuff!   

[ace.cafe]

Nice work Ace!  65bhp out of a 500 single is pretty damn tuff!   

Thanks, but that is potential hp based on flow capacity. It may or may not actually achieve that, based on other things about the build, as you know.
The bottom line is we need to be at or above 54hp at the rear wheel to beat the most powerful modern full-race Manx or G50 bikes that are out there. Those are $50,000 racing motorcycles. If this bike makes even 60hp at the crank, we should be about even with them at 53-54 rwhp. I would suggest it is possible with a very good build and enough rpms.

Without the hi-lift head, it would not be possible.

And this whole race engine can probably be built for under $7500(steel valves and your labor), and the whole bike for probably under $15k total for everything. IMO, that changes the whole perspective of the vintage racing world. A competitive bike for roughly 1/3 the cost!

[High On Octane]

+1

[ace.cafe]

Pics attached below!

Flow sheet data for this head:

Intake:..............Exhaust
Lift......CFM.........CFM
.050"   27.7         25.3
.100"   58.1         54.2
.150"   87.1         83.1
.200"  112.2       110.7
.250"  137.9       133.0
.300"  168.3       156.1
.350"  200.1       172.9
.400"  218.7       186.2
.450"  234.8       196.0
.500"  249.0       196.2
.550"  258.2       196.7
.600"  264.1       199.8

[ace.cafe]

Port and chamber pics attached below:

Ported for a 1.5" carb, such as Amal GP 1-1/2".

[Mr.Mazza]

Nice work Ace!  65bhp out of a 500 single is pretty damn tuff!   

And couple that with a bike and rider who gives 650 twins a run for their money on the track.
He will be unstoppable.

[High On Octane]

That head is beautiful!  Excellent work as always!

[Veeman]

No Phillip Island results - what happened ? I am assuming there was not sufficient time to complete the build, but look forward to hearing of it's first proper race when everything is sorted out.

[ace.cafe]

No Phillip Island results - what happened ? I am assuming there was not sufficient time to complete the build, but look forward to hearing of it's first proper race when everything is sorted out.

The build was completed in time, but it was a close shave, so not much time for sorting, etc.
Unfortunately, it suffered a seized piston in practice, and possibly some other damage which I am not aware of, and it couldn't be repaired at the track. From what I was told, no damage to the head.
So, no results from Phillip Island Classic.

We were all disappointed about that.
It was not an Ace piston, by the way.

[Bullet Whisperer]

It was not an Ace piston, by the way.

It wasn't one of ours, either, just to be clear 
 B.W.