Cam Case Customisation – Cover Chop on Sportster 

Harley-Davidson Sportster cam case customisation

I can do it, you can do it! DIY ‘Do It Yourself’ – for the Bike

This is a complete how to guide on changing the profile of you cam case with a cam case customisation chop.

How it started

Ultimately my desire to take the angle grinder to my precious Harley-Davidson Forty-Eight Sportster started when I saw shots of bikes who had received similar treatment. The raw, rugged and slimmed down look just caught my eye, it looks SICK!” How do I do this myself I thought? A bit of digging on the internet and I was all set. So here’s the how to do a home custom cam case chop on your Harley-Davidson.

It’s worth noting, HD engines do not have overhead cams like modern motorcycles, the valves are driven by cams located next to the crank shaft.  This is why you can see the sexy cam pushrods mounted in parallel to the cylinders, stretching up to the cylinder head valves. Also, as modern bikes have timing managed through the ECU, the timing cover is redundant, it’s purely there for classic old skool looks.

Remember, I’m an account director in marketing…not a mechanic or engineer…so if I can do it. You can do it! Give it a go and give me a shout if you have any questions.

Tools Needed

  • Angle Grinder + appropriate safety equipment (goggles, gloves and mask)
  • Spray paint – 98606BF Noir Texture Harley-Davidson engine paint [or the paint that matches your bikes cam cover]
  • Metal files, ideally a coarse and fine file
  • Wet and dry sand paper
  • Ruler and tape measure [right angle locking ruler is ideal]
  • Appropriate tools for bike assembly

The Recipe

  1. Pick your look

Before you get the angle grinder near your ride I suggest having a good look online for some cam chop shaping options. There are some great designs out there, from simple and minimal like mine through to rather fancy and intricate. Here are a few example looks, you can tell Warr’s London customs have been an influence for me:

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The setup of how the cam case mounts onto the bike means there is some dormant areas. It’s vital to ensure the gasket seal is retained to allow the engine to operate as normal with the customisation, but there is a large area of dormant material that’s not actually fundamental to the operation of the bike. That is the bit we are going to be removing.

 

  1. Drop the oil

As we’re going to be removing the cam cover and gasket we need to drop the engine oil out of the bike. Same as you would for routine maintenance. Unsure how, ask Google or this guy might help too.

Do not skip this part…or you’ll have an oily mess…

 

  1. Prepare to remove the cam case

Before we remove the cam cover and the sprocket cover there are a few parts in the way.

First off, you need to get the exhaust pipes off. Depending how frequently you remove them I’d recommend giving the bolts a quick soak in WD40, hopefully they’ll come off nice and easily.

Secondly, you need to remove the brake push rod linkage. Two little bolts at the front and the circlip and bolt in the middle should get them out of our way. Pop the bolts back in so you don’t lose them or forget where they go.

 

  1. Create cardboard template for Cam Case bolts

Here you’ll be faced with a large number of bolts and it is really important that they go back in the same place. Grab a piece of cardboard and roughly draw the shape of the cam cover to mark the bolt orientation. This gives you a template with the same positioning of the bolts, which means you can pull them out, put them into the template and when you come to put them back together you will know which one is which.

It’s important to remember which bolt goes where – use the template.

 

  1. Remove the cam case and sprocket cover

Carefully loosen all the bolts and place into your template. Use a soft mallet to gently tap the gasket to break the tight seal. You then need to remove the oil hose clip – a small flat head screw driver should allow you to loosen the clip to enable us to slide the hose off.

 

  1. Cover the exposed engine while you work

Use a lint free rag to pick up any of the residual oil. Cover the exposed engine and cam gearing system to prevent any dust or dirt getting in. I recommend standard kitchen cling film or saran wrap. Nothing special.

 

  1. Prepare cam case for chop

Remove the oil pipe union with 7/16th spanner and cover the whole cam case with masking tape. The tape will simply protect the surface from any risk of damage or scuffing.

 

  1. Measure and mark you lines for angle grinding

Carefully mark and measure where you want to reprofile your cam profile. I opted for a 5mm clearance from the gasket seal for a slimmed down look. Remember the angle grinder will make a wide cut line so be careful not to go too tight.

Measure on the gasket dimensions, add 5mm as a safety margin.  I used a right-angle ruler, which enables you to lock on a desired measurement. Lock you ruler and flip the cam case over to mark this on the other side. Complete this at multiple points along the cam case and join them together for a clearly marked cutting line.

The diagonal corners will be marked once the first straight cuts are complete.

 

  1. Double check measurements

Measure twice, cut once!

 

  1. Angle grinder

Clamp the cam case gently in a vice to ensure nil movement and then carefully cut along your marked lines with the angle grinder. Remember to always use correct safety gear.

 

  1. Mark the corner lines & cut them off with the angle grinder

Continuing with the slim profile, I opted for a 5mm spacing on the corners as I was not worried about matching angles. Place the ruler across and mark it before grabbing the angle grinder to snip them off.

 

  1. Smoothing the edges

Angle grinders can be quite aggressive but we need a nice smooth rounded finish. Here we will use metal files. Firstly, use a coarse metal file, before downsizing to a finer finish. Gently file the cut edges smooth with one directional strokes.

For the corner profiles use a fine file with a curved stroke to get a smooth radius with a sharp edge. The curved stroke with the file gives it a more natural finish.

Once finished you should have a rough flat surface with no grinder marks and less prominent filing marks.

Next we need to go even finer on the finish with wet and dry sandpaper. Make sure you keep it wet as you slowly smooth the finish. The goal is to have a perfect surface with no blemishes, no angle grinder marks and no filing lines.

This is a slow process but vital to get a professional finish. It took me roughly 30 minutes of filing and sanding.

 

  1. Prep for spray painting

Following all the dirty work we need to make sure it’s spotless before we spray paint. Remove the masking tape, which was purely for protection. Then it’s into the kitchen sink, hot soapy water and a good clean down.  You then need to fully degrease it with some brake cleaner.

Make sure you get rid of all the grime, finger prints and grease ready for spraying.

 

  1. Spray painting

Purchase the correct paint to match your cam case / engine case, however you could of course change the colour of the case at this stage. I opted for official Harley-Davidson textured black – 98606BF Noir Texture via my local Harley-Davidson dealer. No doubt there is an after market version but I went straight to the source to get the good stuff.

Apply paint following the directions on the tin you purchased. I went for 4 coats covering both the new exposed edges and the rest of the casing to ensure no visible blending lines in the paint.

 

  1. Leave to dry or oven dry following paint manufacturer instructions

 

  1. Remove paint over spray on seal surface

With the nature of spray painting you might have some over spray on the surface where the gasket will seal. Use a sharp razor blade, from a Stanley knife, to gently scrape off all the excess paint.

 

  1. Final clean and prep before re-assembly

Back in the kitchen for a hot soapy clean. Once dry apply multi-purpose grease to the new gasket and put gasket in place on the bike. The grease will help the gasket swell, which gives the seal required.

Re-attach the oil pipe union with thread-lock to make sure that stays in place. Screw it in finger tight in the correct vertical orientation.

Finally, prime the mating shaft surfaces with some engine oil.

 

  1. Refit cam case

Due to the high tolerance fit of the cam case, sliding this back on can be tricky. Work to align the mating surfaces by looking at the gap around the edge. Do not be tempted to use a hammer and bash it on. You must be patient and gentle. Once you’ve found the sweet spot you’ll be able to slide it on pretty effortlessly but it’s about finding that sweet spot.

Return the correct bolts to their original location utilising the cardboard cut-out created on removal. Using you bikes manual follow the diagram for the correct tightening sequence and torque values for fitting the cam case.

For the torque, the manual says 10.2-13.6 Nm. I went for 12, somewhere in the middle.

Here is the pattern and values from the Forty-Eight Sportster manual.

 

  1. Reassemble the bike

Get the pipes and brake linkage back on. Note I have chosen to leave the front sprocket cover off to give a more rugged look. You can buy aftermarket guards if you’re worried about the exposure.

 

  1. Cam case chop customisation complete!

Harley-Davidson Sportster cam case customisation final reveal

 

Time Required

It’s a pretty swift job, I would anticipate around 4 hours plus drying time for the paint.

 

Ease of Completion

Hopefully I’ve shown how easy it is. It’s something completely achievable at home if you have the required tools. Get out there have a look at what shapes you like and try it out.

 

Crowd Reaction

Given how cheap this custom is it’s well worth the time doing it. Anyone can change the pipes, pegs or air intake but it takes a little more energy and precision to take an angle grinder to you ride. You might get the odd guy moaning that your sprocket is vulnerable but really…unless you’re riding through mud it’s not going to cause any issues. Winner on the streets I’d say!

 

£££

If you have the tools the only cost is going to be the paint and a new gasket, roughly £20-30. Very cheap given the finished look.

 

Highlights of a cam case customisation

  • Minimal cost for a great look you can do yourself
  • Adds a great raw rugged look to your ride
  • Easily achievable in a weekend
  • This will make you more aware of how your engine operates 😊

 

Tips From Experience

  • Soak any bolts in WD40 before removal
  • Ensure your cam case is firmly clamped before using the angle grinder
  • Thoroughly clean all dirt before painting and re-assembly
  • Apply nice thin even coats of paint to avoid drip lines
  • Make sure you to not compromise the gasket seal with your design.

 

Overall Rating

This simple home custom gives an epic, rugged and aggressive look. You can see the front rear sprocket and have a new slim profile. Simple custom for a great finish.

I CAN DO IT. YOU CAN DO IT.

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