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Thursday Edition


5-Ball Racing 2012: Chapter 2

A Long Distance Twin Cam Rebuilt for More Miles

By Bandit with photos by Ray C. Wheeler
3/25/2012


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Ray and I are planning to attend the Bub Motorcycle Speed Trials in Bonneville this coming September with two motorcycles. Ray rode his touring 2004 Dyna Glide for 50,000 miles and rode from San Jose to Bonneville in 2009 and set two records with saddlebags on his bike. Then he got serious and added a Aerocharger turbo charger and rode another 30,000 miles before returning to Hardtails, in San Jose, California, for a tune-up. His engine was toast.

The Bikernet.com 5-Ball Racing Team convinced Ray to pull the 124-inch monster and put it in a Bonneville-dedicated chassis for 2012. So what was he going to do with his touring Dyna? He replaced his highly modified stock cases with S&S racing cases. Randy at Hyperformance, in Pleasant Hill, Iowa, repaired the Harley-Davidson cases and sent them to our headquarters. We went to work with Eric Bennett to build him a calm, long-distance, Dyna hot rod street motorcycle.

The original, before tear-down.
The original, before tear-down.




We ordered a brand new Revtech big bore kit. It would take his stock 88-incher to 97 inches. We grabbed a Screamin' Eagle hydraulic cam tensioner plate for the longest lasting durability. Then we started to search for a lower end and found out that there are two reputable Twin Cam lower end rebuilders, and one is Dark Horse, in Newton, Wisconsin, who replaced the no-race stock rods with I-beam rods with races for much improved heat dissipation and longevity. Plus they replaced and TIG-welded the crank pin into place to remove the chances of flex and slippage, and balanced the engine to their secret balance factor for this engine configuration, for smooth running, less vibration, and longer lasting engines.

Pressing a cam bearing into the H-D hydraulic cam plate.
Pressing a cam bearing into the H-D hydraulic cam plate.




Ray, our hot rod nut, slipped in a nefarious phone call to John, the master builder at Dark Horse, and tried to jack the stroke order from 4 inches for an 88-incher (97 inches with the CCI kit) to 4 3/8 for a 96-cubic inch configuration (or 106 with the same RevTech big bore kit). We're not exactly sure whether he succeeded or not--Hang on. The Harley cam drive system also comes with a larger capacity oil pump, which lends to the overall durability of any Twin Cam configuration.




This engine, designed for long distance, reliable touring, was coming together with the absolute best-of-the-best components. Eric volunteered a set of worn, stock heads to be rebuilt next door at the nirvana of flow, Branch/O'Keefe command center. The pristine machine shop is lined with heads destined to be shipped to locations all over the country, Europe and Japan. John keeps an inventory of over 100 sets of heads and offers a trade-out for pre-rebuilt heads, for faster turn-around, or he will perform his magic on your set of heads and have them back in the mail within two weeks.

Stock set of double wound springs, w/heavy metal keepers on top. This came from an early Twin Cam, still with 5/16-inch valve stems, before the factory cheapened the valves, and added poor quality, oil collecting valve collars.
Stock set of double wound springs, w/heavy metal keepers on top. This came from an early Twin Cam, still with 5/16-inch valve stems, before the factory cheapened the valves, and added poor quality, oil collecting valve collars.



Jerry Branch opened his shop in 1969 and was recently inducted into the Trail Blazers hall of fame. He's improved the breathing side of champion race team engines ever since. One of his early employees was the young John O'Keefe, who joined the team in 1975, and is still marveled by the energetic 88-year old Jerry Branch. Jerry is currently working with Dan Gurney to build faster cars. John took over the business seven years ago and has kept the high-flow fires burning.

Precision machined Titanium keepers on a double wound springs for lighter weight, and easier RPMs.
Precision machined Titanium keepers on a double wound springs for lighter weight, and easier RPMs.



Their heads are much more than tried and true porting or even welding up and enlarging valve pockets for large valves, reshaping combustion chambers, or shaving heads for added compression. They replace every head-related component with endurance-tested, state-of-the-art titanium valve collars. In the case of late model TwinCams, they replace the leaky, spindly, stock valves with stronger 5/16 nitrate valves.

Twin cam heads from Branch flow about 30 percent better than stock heads across the valve opening range. Actually, stock heads flatten out in one position and don't flow any additional capacity throughout the remaining valve opening sequence. In that area, Branch heads kick ass.

Polished intake, with a microscopic fish hook finish for maximum air flow velocity and thorough fuel mixture.
Polished intake, with a microscopic fish hook finish for maximum air flow velocity and thorough fuel mixture.




They reshaped the heads through years of trial and error to allow for larger, better flowing valves in the optimum position, since the stock heads didn't burn all the fuel, impeding efficiency in the factory engines. The area around the valves became smaller, but they were able to speed up the velocity of the air passing through. In a smaller area, they were able to add more space around the valve.

John squeezed in a 1.94-inch intake into the combustion chamber, compared to the 1.85-inch stock valve. They were able to design in a larger valve with more functioning space around it. The crest in each port allows for more valve guide support and still enhances the port flow.




John replaced the edgy stock cast iron valve guides with bronze magnesium components.

The before shot.
The before shot.



"I like these work-hardened valves and guides, because I can run a much tighter valve stem-to-guide tolerance," John said.

The tighter tolerance affords heat dissipation from the valve through the guide. The enhanced grain structure in the guides acts as a heat sync pulling blistering temps off the valves. All these elements make for a longer lasting valve train.

These amazing aerodynamic guides come with Viton seals built into the structure of the guides. They also run a thicker, more robust exhaust guide for additional heat dissipation.



For Evo heads, the Branch team installs one-piece stainless valves with chromed stems and stellite tops where the valve meets the rocker for additional hardened strength. For twin cams and baggers, John recommends black nitrate valves with a Teflon coating.

"I use the stainless valves in Evos because the guys don't lug them," John said.

Their valve seats are nickel chromium and capable of running valves up to 2 inches. The biggest valve you can put on a stock seat is 1.90. The Branch O'Keefe seats are machined with an interference fit of .007-inch so they will never rattle in the heads or ever fall out. Factory seats are only .0025-.003 larger than the hole in the head. He heats the heads to 300 degrees, and freezes the seats before assembly. The nickel chromium seat material will take any unleaded fuel and won't pit.

Stock set of valves
Stock set of valves



Each valve seat is cut at 45-60-30 degrees, three angles. With porting, it is the equivalent to a 5-6-angle valve job. Each valve is ground to 45 degrees, and John uses a special carbide-honing bit to ream the guides. It is designed with a reverse spiral so it runs clockwise and it is set to slip fully into the guide before it begins cutting, for an absolute straight ream. Each bit costs over $200.00.

Fresh set of 5/16 stem Nitrate valves.
Fresh set of 5/16 stem Nitrate valves.




John and the Branch team hand-lap each head. "We can modify heads for any performance application," John said. "It is no longer a one-size-fits-all world."

The master in the clean room is Paul, a former Honda race tuner. "He's great at tech support," John said, and I could tell he wanted to talk to the milling machine more than me.

Using blue dykem to make it easier to see the results of Branch hand-lapping.
Using blue dykem to make it easier to see the results of Branch hand-lapping.



"We like to find out what a guy rides, and how he rides," Paul said. "It helps to find out what they have in their engine, what kind of intake, and carb."

Titanium vs. steel collars and keepers
Titanium vs. steel collars and keepers




Sometimes, they polish intakes and Paul can make carb configuration recommendations and carb tuning. Even their valve springs are top of the line. "We have a five-year track record, of no failures or pressure drop," John said. "Some springs drop 20-30 pounds of pressure in a race bike after just 50 dyno pulls."

Precision machined Titanium keepers on a double wound springs for lighter weight, and easier RPM's.
Precision machined Titanium keepers on a double wound springs for lighter weight, and easier RPM's.



The springs are shot-peened, stress-relieved and they test at 180 on the seat.They are refined and capable of .675 cam lift. John uses only chrome moly collars and retainers. Branch heads are offered to a couple of configurations:

While the Branch team massaged the heads, Eric Bennett kept inventory of our parts rolling into his shop.
While the Branch team massaged the heads, Eric Bennett kept inventory of our parts rolling into his shop.




#4 Heads for Twin Cams and Evos

This performance head is designed to fit a variety of engine configurations and riding styles. Branch #4 heads work with both the Twin Cam or Evo applications of varying displacements. Compression ratios for these heads are 9.6-1 for the Twin Cam and 8.9-1 for the Evo. This results in a head that performs much higher than its stock counterpart.

The completed, state-of-the-art Branch O'Keefe head. Like a fine watch.
The completed, state-of-the-art Branch O'Keefe head. Like a fine watch.




PT Heads for Twin Cams
 
The Branch PT head is specifically designed for touring riders with 88-inch or 95-inch Twin Cam engines. The benefit of this design is that it provides low-end torque that is so often required for heavily loaded, long-distance motorcycles. Compression ratio is based around a figure of 9.5-1 when used with Branch flat top pistons. The result is power where it’s most needed: in the 2000-4000 rpm range.

Here's some teaser shots from upcoming articles. This bike is about ready for a break-in run from San Jose to Los Angeles.
Here's some teaser shots from upcoming articles. This bike is about ready for a break-in run from San Jose to Los Angeles.




In the next chapter on the 5-Ball Bonneville Raycer we will bring you another tech on the completion on this motor with Crane roller rockers, manufactured by S&S, Fueling cams, lifters, easy-to-adjust pushrods, and a brand new Yankee Ingenuity EFI throttle body that is sure to rock the fuel injected world.







96-Incher Sources
 
Bennetts Performance, motor build
1940 Freeman Ave Signal Hill, Ca. 90755
562 498-1819
 
Click the image for more info.
Click the image for more info.

Branch/O'Keefe, head work
1940 Freeman Ave Signal Hill, Ca. 90755
562 597-2850
 
Crane-Roller Rockers
Toll-Free: 1-866-584-3750
Toll-Free International: 00-1-866-584-3750
Fax: 608-627-0480
E-mail: MCtech@cranecams.com
 
Advertisement

RevTech , 96-inch piston/cyclinder kit

18225 Serene Drive Suite # 150 Morgan Hill, Ca. 95037
 
408 778-0500
 
Dark Horse Crankworks, lower end kit
10629 Highway 42 Newton, WI 53063
920 726-4990
 


Fueling, cam kit
17215 Roper Street Mojave, CA 93501
 
Hardtailz, axle to axle
354 Umbarger Road, Suite 9
San Jose, CA 95111-2000
 
H-D Screamin Eagle, cam plate/oil pump
P O Box 653
Milwaukee, WI 53201
 
 
Hyperformance, case repair
5152 E University Ave
Pleasant Hill, Iowa 50327
515 266-6381

Advertisement

JIMS Machine
555 Dawson Drive, Camarillo, CA 93012
Phone 805-482-6913 FAX 805-482-7422
www.jimsusa.com

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Samson Exhaust
655 Tamarack Ave, Brea
California
92821
1.888.572.6766
Fax: 1.714.518.2466
http://www.samsonusa.com/
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Yankee Engineuity, throttle body
Div of Paughco
30 Cowee Drive
Carson City, NV 89706
800 423-2621







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Reader Comments


hey bandit,

long night ? chapter 3 same as chapter 2....just saying

dave
someware,ny, NY
Tuesday, April 03, 2012
Editor Response You're right, something internal and we're working on it. Thanks for letting us know!
Nyla
For your readers who are attempting to learn from your tech articles and for readers such as myself who sometimes forget what they came into a room to do....some of the pics and text don't jive. Of course many components are known by a variety of names, but that would best be addressed as well.

Keepers, collars, retainers, and the materials they are made of were a bit...lets say..ambiguous. Now if you can tell me what I came in here to get.

Sam Burns
San Marcos, TX
Friday, March 30, 2012
Editor Response Hey,

Sorry about that. If you need a specific question answered, we will dig until we discover the information you need. Just let us know.
--Bandit

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