Lunati Cams and Feuling Cam Plate Install

Lower End Hop Up

Here are the parts we were going to use to upgrade the lower end of the Fat Boy; Feuling pushrods, HP+ Oil Pump, and Cam Plate, and Lunati cams and lifters.

1 To get started Dustin set the Fat Boy up on a lift and removed the air cleaner and Pro Pipe exhaust system. Since we were installing a set of adjustable pushrods, the stock pushrods were simply cut out using a large set of bolt cutters. This method made for a clean cut with no worry about metal shavings dropping into the engine.

2 With the 10 fasteners removed, the cam cover was pulled free exposing the stock cam plate and camshafts. Dustin was sure to have a catch pan handy because plenty of oil was still setting in the cam chest.

2 With the 10 fasteners removed, the cam cover was pulled free exposing the stock cam plate and camshafts. Dustin was sure to have a catch pan handy because plenty of oil was still setting in the cam chest.

3 After removing the lifter blocks, the original roller lifters were removed and relegated to the spare parts bin. With such low mileage, they were good candidates to keep around for an emergency.

4 Using JIMS tools, Dustin rotated the tensioner spring arm until it could be safely pinned in place, effectively removing tension on the outer chain.

5 Another JIMS tool was slipped between the crank and cam gear to lock them in place so the retaining hardware could be removed.

6 The outer chain and gears were simply slipped free and set aside.

7 Dustin pulled the attaching hardware from the cam plate and it pulled free with the camshafts still attached.

8 Dustin then pulled the early style factory inner cam bearings from the cam chest using the proper puller. A pair of upgraded Torrington bearings was readied for installation with a bit of anti-seize spread on each. A JIMS installation tool was utilized to align and install the bearings properly.

9 Grease was applied to the Feuling HP oil pump surfaces before it was installed with fresh O-rings. The grease would lubricate the pump on startup so as not to destroy it.

10 Quite a few parts were needed from the stock cam plate so Dustin prepared it for disassembly.

11 Since this was an earlier Twin Cam bike, it was necessary to press the camshafts out of the cam plate. Removing the cams was necessary so we could get the inner chain off to be reused. Also, the tensioners and cam retaining plate were gathered to transfer over to the Feuling cam plate.

12 Still at the hydraulic press, the Feuling billet cam plate received the included tensioner pins and guides along with new bearings.

13 The new Lunati camshaft specs are .510 inches of lift on both the intake and exhaust when using the factory 1.625 rocker arms. With a 105-degree valve centerline, the total duration @ .050 was 235 degrees for the intake and 239 degrees for the exhaust. These cams came with a ground-in additional 4 degrees of advance. Notice the specialty tool designed to install both Twin Cam bumpsticks evenly and at the same time. The original inner chain was reused once the camshafts’ timing marks were aligned.

14 Completely assembled and lubricated, the new parts were slipped back into the cam chest with special attention paid to the oil pump alignment and cam bearing engagement.

15 Dustin popped the transmission into Fifth gear and used the rear wheel to bump the engine over a little at a time until the outer cam chain timing marks could be aligned.

16 Once in position, the locking tool was employed to prevent the engine from rotating, and the gear retaining bolts were torqued with a bit of threadlocker.

17 Lunati’s hydraulic roller lifters simply dropped into place. We buttoned them up with the original ant-rotation pins and stock lifter blocks.

18 Feuling states its adjustable pushrods can be used with the MoCo’s pushrod tubes. F’NA wasn’t really happy with the limited amount of space the stock tubes allowed so a set of Colony Machine pushrod tubes were purchased. Colony’s tubes allow the lower tube to slide up much further making adjusting the pushrods a snap.

19 The exhaust was bolted back onto the Fat Boy and the Dynojet Power Vision was readied. Dynojet’s Patrick Daniels logged into the system and uploaded a basic software tune for the EFI that would get us off the ground and running right.

20 F’NA Cycle has its own performance intake system ($249 black or $279 chrome) and wanted to see how it would alter our dyno numbers over the Stage 1 open filter.

21 The proper support bracket wasn’t available at the time, but for our dyno session it wasn’t necessary since the bike wasn’t going to actually be ridden down the road. Dustin simply bolted the F’NA intake tube to the Harley’s throttle body.

22 Next, the breather crossover was mounted to each cylinder head to catch the vapors.

23 A K&N; filter was chosen by F’NA for its easy cleaning and high-flow capabilities. Still strapped to the dyno, Dustin made a number of pulls to gather the information we were seeking. Some odd things occurred and just proved that a proper combination of parts was key to achieving a smooth and powerful engine. Without a precise EFI tune for this specific parts combination, the F’NA intake lost 2.4 hp at the 5,700-rpm peak, but gained 1.0 lb-ft of torque at the 4,100-rpm peak. That wasn’t the interesting part though. The new intake gained quite a bit way down low where the bike would spend the majority of its time running. At 2,550 rpm, F’NA’s tubular intake made 1.5 hp and 4.0 lb-ft of torque more than the Stage 1. That is a jump that could be easily felt in roll on throttle. Low rpm increases ran from basically zero all the way to the 4,500-rpm mark before the F’NA parts star losing to the Stage 1 breather. Next issue we will delve into the new Power Vision for a more in-depth article on how the unit works.

Lunati may be a new name in the mouths of the American V-twin market, but it is no stranger to creating parts that generate good engine performance. With a fresh line of camshaft applications available to fit most any Twin Cam Harley-Davidson from ’99 on up, we thought the time was ripe to take a closer look at the company’s offerings and put them to the test. Starting with an extremely low mileage ’04 Fat Boy still sporting its Stage 1 intake and exhaust additions and 88ci displacement, the decision was made to keep the modifications similar to what many would do to their own bikes. This install was designed to best showcase what the parts would do for you and is not about making the most power as possible from the package.

With that in mind we managed to stay rational and chose a pair of Lunati’s camshafts ($265.99) that top out at .510 inches of lift with the stock rockers and did not require changing the valve springs. A matching four-pack of hydraulic roller lifters ($14.99 ea.) was ordered to go along with the new bumpsticks. Knowing the added stresses on the original cast cam plate can get quite high with larger camshafts, we placed a call to Feuling for one of its much stronger 7075 billet cam plates ($399) to support the additional power. A HP+ oil pump ($425) from Feuling should give us a solid rise in oil pressure and oil return scavenging to keep the rotating parts alive for a long time to come. Additionally, Feuling supplied us with a set of adjustable pushrods ($239), saving us the added labor time of pulling the fuel tank and disassembling the rockers. Our Fat Boy guinea pig was an EFI-controlled machine so Dynojet’s Power Vision was chosen to program the Harley’s ECM with the correct information on fuel and timing for the new power combination.

In the capable hands of Clarke and Dustin Dunlap at F’NA Cycle and Performance in San Bernardino, California, our H-D was transformed into a much more potent riding machine. Hills, passengers, freeway passing, and stoplight action was much improved and tickets were easily just a twist of the wrist away. Before tearing into the Fat Boy with its open air cleaner, Vance & Hines Pro Pipe fit with a competition baffle, and a factory Stage 1 EFI download, the bike managed to put down a respectable 72.1 horsepower and 77.5 lb-ft of torque as a baseline. With the Lunati cams and a custom tune from Patrick Daniels at Dynojet, those numbers rose to 79.8 horsepower and 84.5 lb-ft of torque. That was a step up of 10.7 percent horsepower and 9.1 percent torque with similar increases across the spectrum. Those numbers were about what we expected and made a difference in the bike’s feel when the throttle gets rolled open. HB


Anaheim-Fullerton Harley Davidson | (714) 871-6563

Colony Machine | (330) 225-3410

Dynojet Research | (702) 399-1423

Feuling | (866) 966-9767

F’NA Cycle and Performance | (909) 386-7366

Lunati | (662) 892-1500

[email protected]