A Royal Enfield forum for the people

[Crispyduck]

Hi, I'm a newby to this site,

Does anybody have any info on the the UCE Fireball #3 cylinder head.

I've been looking for a better cylinder head for my UCE bullet and I've heard ACE has now started producing one especially for UCE engines?

Any info would be welcome

Cheers

Mike

[Guaire]

Hi Mike - What year and model Royal Enfield do you have? Are you in the US, where?
Fireball #3 is my serial #. The UCE Fireball fits the 535cc CGT. Fireball heads are machined from a solid block of aluminum. The cost is in the thousands.
Our Clubman Kit 1 and 2 cost is in the hundreds. In my 2011 B5 Bullet, I'm running a Clubman Kit 2 head and ACE Performance cams. The Clubman Kit 1 works with your stock cams. These cylinder heads use our stainless steel one piece valves.
Here's a post I put up on the old forum.

"I got my 2011 B5 down the GW Parkway as far south as Mount Vernon. On the way back I stopped for this photo on the Potomac River.
This machine has the first ACE Motors Clubman Kit 2 cylinder head with our [ACE Performance] cams installed as well. The head has stainless steel valves, with the intake 1mm larger than stock. The Clubman Kit 1 has standard springs. This one has bee hive springs. This set up is not for all out race results. The regular tune, as you know, starts strong. Then, the motor just runs out of breath. The revs get higher but the power just doesn't climb. This cam and head breathe better than stock. The usual, off idle torque power, extends up to the rev limiter. When you are in the power band - anywhere...the power keeps coming on. This Bullet a real pleasure to drive. There's a progressive power band all the way to the top."

The stock steel valves have their heads friction welded to the stems. Under hard and hot driving the exhaust valves can drop their heads. These valves are one piece affairs. In stock, I have valves for the Clubman heads and ACE Performance cams.

The B5 of mine is using a Power Commander V, set up with the AutoTune system.
We can consider what options will work for you when we know what you're running now. Here's the Facebook page for ACE Motors. I'll also put up the YouTube channel URL.
https://www.facebook.com/Wguaire
https://www.youtube.com/channel/UCrzPg5 ... 16-xYGue_Q

Bill G.
Some pics....

[Crispyduck]

Hi Bill,

Thanks for the reply and info.

My bike is a 2016 UCE bullet 500 sold for the asian market. It was one of the last carburetor versions sold before they went to all EFI.

I've done quite a lot of work on it since, as follows:

- Changed cylinder and piston to give 535cc (Hitchcocks kit with flat piston crown)
- Changed crankshaft to 612cc (Hitchcocks longstroke crank)
- Changed head with a GT535 head
- Changed carb to amal 30mm MK1 (also tried 32mm but prefered 30mm)
- Reverse cone type silencer
- K&N type pancake filter
- MSD PN4217 programmable ignition and MSD coil
- Modified cams with 1mm additional lift (tried hitchcocks street cams but had some issues)
- Hitcocks valve springs to accomodate extra lift.

The CR is about 10:1 so i fitted a manual decrompression plug so i can start it easily and avoid sprag clutch issues.

The bike goes fairly nice compared to a standard bullet 500 but i have 2 issues.

Firstly the valve guides wear quickly plus i get an annoying ticking noise from the valves due to the rocker geometry. I've done various checks so i know its not the hydraulic tappets causing this. Seems to be due to the rocker dragging across the tip of the valve.

Secondly the power seems to flatten off above 3500rpm, instead of continuing to climb.

I was looking for a kit which replaces the standard valve rockers which is why i was thinking a fireball kit.

Cheers

Mike

[Crispyduck]

I forgot to mention, I'm from the UK but im working in Indonesia which is where i bought the bike.

[Ace.cafe]

Power falls off at 3500 because you are trying to feed an increased displacement with a reduced inlet tract.
It needs at least 34mm carb, and 36mm might be better.

Higher valve lift always causes increased wear on the valve train, but the RE factory stuff can be pretty bad in some cases. Might try some harder guide material like 936 bronze, and perhaps try a different set of factory rocker arms which might luckily be better made. RE quality and accuracy varies wildly.
Not sure about your aftermarket cams. They might be a bit aggressive, or not well suited to the factory geometry.

Our Fireball roller rockers are specific to our billet head which is a very big investment. But it would be a great thing for your bike if you can afford it.

Last recommendation is to do a cold-cranking compression test on a quality compression gauge in the spark plug hole with wide-open throttle to make sure the compression is below 155 psi. Any compression over 155 will risk eventual piston failure from detonation.