[ace.cafe]

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

Yes. Good point.
Thanks for making that clear too. I don't know who made that piston in the Aussie bike, or what the specs were for it. We made a polymer mold of the finished chamber shape and supplied that to Guy, so he could work with his piston maker.

[Mr.Mazza]

It was a JP piston, couldnt take the power and cracked the skirt which ran through the hole crown then bit into the cylinder.

[ace.cafe]

It was a JP piston, couldnt take the power and cracked the skirt which ran through the hole crown then bit into the cylinder.

I wish he had discussed that with me. I am afraid that JP just doesn't make the grade for performance work. They are okay for a low revving plodder like a bone stock Bullet, and that's all. The low price doesn't turn out to be so low after it fails and takes out the engine.

[Adrian II]

With my project bike in mind, are your Fireball pistons cast or forged?

A.

[Mr.Mazza]

I wish he had discussed that with me. I am afraid that JP just doesn't make the grade for performance work. They are okay for a low revving plodder like a bone stock Bullet, and that's all. The low price doesn't turn out to be so low after it fails and takes out the engine.

I fhink he is looking at Forged pistons from a shovelhead, for cost vs strength.

[High On Octane]

That just seems silly.  He already spent the money on the head job, why not just buy the piston FOR the head that is tried and tested to be a great piston?  Especially after he already blew it up once with a sub-par piston? 

[ace.cafe]

I fhink he is looking at Forged pistons from a shovelhead, for cost vs strength.

The dome isn't right on Harley pistons, and the valve reliefs are on the wrong angle because the valve angle is different than the Bullet. Plus the pin diameter is different which makes it more difficult to go back to a correct piston for a Bullet later. And a larger pin is heavier.

Believe me, those things have all been tried many times before with less than stellar results. I hate to see people repeating mistakes made by others in the past. These things don't turn out less expensive. In the end they are more costly because they need to be replaced with proper stuff in the end anyway.
He needs a real piston that is custom made for that application, that has the right dome and valve reliefs, and very lightweight construction for the rpm range intended. He has time to do it now that the Phillip Island race is past.

My 2 cents.

[Mr.Mazza]

That just seems silly.  He already spent the money on the head job, why not just buy the piston FOR the head that is tried and tested to be a great piston?  Especially after he already blew it up once with a sub-par piston? 

Its all about the money too Scottie, this is with the old head aswell so only 40ish hp
Work is dry atm so everything is on hold for him at the momenf

[Veeman]

  Flow bench data for the head is interesting in that the intake flow is considerably greater than a 92 bore Summerfield Manx Norton, and the engine being compared makes just better than 60 rwhp on gasoline.
The methanol will need a dash of Nitro to get up to that level!

[ace.cafe]

  Flow bench data for the head is interesting in that the intake flow is considerably greater than a 92 bore Summerfield Manx Norton, and the engine being compared makes just better than 60 rwhp on gasoline.
The methanol will need a dash of Nitro to get up to that level!

Well, we anticipated that flow would be higher than the various Manx bikes out there, because we did some digging to try to find out some of that info, although it was very guarded info and hard to find. We also found the published cam grinds available for the Manx and G50, and they seemed to all have less lift at the valve than what we have on this head with the cams being used and our roller rocker ratio.

So, we have what appears to be greater flow, and higher lift than the best of the competition. What we don't have is the shorter stroke. In order to make the most out of the available flow, we need to have a lot of revs, like they have. And so this is the challenge with the long stroke. Things have been done in the BW racer to try to reach into the mid-8000's rpms, and it might be able to get up there with the necessary sorting out over time this year. If not, we may make some changes along the way to improve it. It's a new ball game with these heads, and we will probably need some time and work to get it all dialed in to the best of its capacity.

I don't think we'll need any nitro, but we will need the revs to get into the 8000's rpms. The flow in this head will allow 60hp at the rear wheel on gasoline, if the revs get where we want them.

[Bullet Whisperer]

We should soon be seeing how a Big Head behaves at up to possibly as much as 10,000 rpm. The build of a very different RE racing engine gets under way next week 
 B.W.

[ace.cafe]

We should soon be seeing how a Big Head behaves at up to possibly as much as 10,000 rpm. The build of a very different RE racing engine gets under way next week 
 B.W.

That will be very interesting!
Watch those valve springs!

[Chuck D]

We should soon be seeing how a Big Head behaves at up to possibly as much as 10,000 rpm. The build of a very different RE racing engine gets under way next week 
 B.W.

10,000rpm !
Take that, Mr. Pomeroy!

[Arizoni]

Seeing as how the stress levels go up by the square of the increase in speed, that's going to be quite a feat unless a very short stroke crankshaft is going to be used. 

Long stroke engines with their large movement of the big end don't like high speeds.
Come to think about it, piston rings and pistons don't like moving at high velocities either.

Wishing him luck.

[ace.cafe]

Seeing as how the stress levels go up by the square of the increase in speed, that's going to be quite a feat unless a very short stroke crankshaft is going to be used. 

Long stroke engines with their large movement of the big end don't like high speeds.
Come to think about it, piston rings and pistons don't like moving at high velocities either.

Wishing him luck.

I don't want to steal the thunder, so I won't spill the beans. Suffice it to say that the factors involved are known and understood. The engine will be made known when BW reveals it.