Cam upgrade

Article And Photos By: Tony Tucker

e are always chasing more power. We live in a time where we are pretty lucky to have a handful of different motorcycles in the w

Cruiser/Touring motorcycle market with impressive power and torque numbers right off the dealership floor. But even still, we always want more. With all the trends that come and go, the one constant trend is always HORSEPOWER. In our shop, Tucker Speed, we specialize in all things performance when it comes to late-model Harley-

Davidson motorcycles and, more specifically, the new Milwaukee-

Eight engines. In this article, I want to talk to you about one of the first performance upgrades you should do to your new M-8 motor. The cam upgrade. With the M-8 being on the market for almost 5 years now, the aftermarket world has zeroed in on what’s working and how to unleash the potential in the motor. We will discuss some of the best “boltin” cams on the market today for this article. “Bolt-in” meaning that there are no other parts or mods needed with the cam install like high lift valve springs, adjustable pushrods, or a need to worry about valve to piston contact. Some of the cams that we have found to have really good results on the

Dyno are the S&S 475 and the

Woods 22X-E. Both have given us great HP/TQ numbers on the Dyno but, more importantly, create a very fun motorcycle on the streets. In these images, you will see that we are installing the S&S 475 cam in a 2018 FXLR Lowrider. Although the cam is a “Bolt-in,” we would strongly recommend installing an upgraded camplate and oil pump with the job. We are also installing adjustable pushrods to make the installation a little easier because we will not remove the fuel tank or the rocker boxes. We are also installing the S&S tappet cuffs. The stock cuffs are plastic and are likely to break or warp from heat causing further damage. The other key is to make sure to install Torrington style (full complement) inner cam bearing. Meaning that there is no

cage in the bearing. It’s a full stack of needle rollers and far less likely to fail.

As you can see in picture #1, I like to lay out everything in the kit and take an inventory and also inspect all parts to make sure I have everything I need and there is no damage from shipping or anything of the sort. Once I have verified that I have all my parts, I proceed to the teardown portion of the job. It’s always good practice to follow your model-specific service manual for this step. But in this case, I have opted to not remove the rockers. I put the cylinder I am working on at TDCC and cut the stock pushrods out with bolt cutters. You must be careful when doing this, as the pushrod still has slight tension on it from the lifter. Once you’ve got them out of the first cylinder, find TDCC on the other cylinder and repeat.

In pic #2, I have completed the teardown process. It’s essential to keep everything clean here. At this point, I like to do a crank runout check just to see where the crank is at. Whether it has 10 miles or 100k, I want to see where it currently is at. I personally use the crank runout tool from Feuling. It’s simple and easy to use. The first step in the install is to remove the old inner cam bearing and install the upgraded one. This requires a special tool. Companies like Jims Tools or George’s Garage make very nice stuff.

As you can see in pic #3, I have gotten the cam, pump and camplate installed. Be sure to follow the instructions that come with your specific kit. At this point, it is very important to do a proper oil pump alignment. Usually, each manufacturer will have its own version of how to perform this. It’s a good idea to follow the instructions for your specific brand. But if all else fails, refer to the factory manual. Be sure to use lots of assembly lube. You don’t want to start everything up dry.

Pic #4 I have aligned and torqued the plate and pump, installed the chain sprockets. Now, you want to perform a gear alignment check. A shim behind the cam sprocket will space it in or out to achieve proper alignment. The spec is .010”. I usually like to get it under .005” personally. And the final step is to install the chain and torque the cam and crank sprocket bolts. You can see in pic. #5 there is a sprocket locking tool from Jim’s Tools to lock the sprockets together during the torque procedure. Lastly, install the cam chain tensioner and torque to spec. After all of this is complete, it is critical to have the motorcycle adequately tuned. Many really good Dyno tuners around the country can get the fuel map properly set up and running correctly. My preferred tuner is the Dynojet Powervision. But there are other tuners like Thundermax or TTS Mastertune that can do a great job as well.

In my opinion, these “bolt-in” cams can really take your M-8 powered motorcycle to another level without breaking the bank. So, for all you horsepower junkies, I hope this has helped answer any questions about how to start to get the most from your motorcycle. Like we say here at Tucker Speed, we like to “make power, not friends.”

Tony Tucker

Tucker Speed