Installing the New Cams

With Steve in town we're getting a lot done this week. Tonight's project was to install the new cams and set us up for checking the valve clearance and finishing up the top end. Hopefully by the time we're finished tomorrow night, we'll be able to start her up.

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Using 1/2" PVC sprinkler pipe couplers and the short head bolts, we temporarily fastened down the cylinders so they wouldn't unseat as we were working on the cams. This was one of the very helpful suggestions NHRS made in their installation instructions which made this part of the job a lot easier than it otherwise would have been.

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I removed the fasteners alternating across from one another until they were all removed and I could pull of the cover.

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Before I started removing the fasteners, I sketched out an outline of the cover with holes to retain the fasteners so I could make sure the same fasteners got replaced into the same holes when we put it back together. I did this because the fasteners aren't all the same size. Although it is pretty obvious which fastener will go where, I liked the redundancy of this trick and it made it easier to just keep track of everything.

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It looks like the previous owner definitely went with an aftermarket part here so the rivets on the OEM cover had been replaced with screws. We scribed a reference point with a pick on the timing module and the inside of the case so we could match it all up again when we put it all back together on re-assembly.

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After pulling the timing module out of the way, we could remove the single fastener that held the timing cup in place before removing the case.

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With all the fasteners removed, I could now gently pull the cover off. Because this is a place usually filled with oil, I put the oil pan underneath the bike to capture any oil that might still be in the bike when the cover was removed.

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The cams are all numbered from left to right #1 through #4 with the small pinion gear in the bottom middle of the assembly. We removed, wiped down, and set the old cams aside.

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Behind the pinion gear is the oil pump gear that I had heard was prone to failure, so I had a new brass gear to replace it. You can see the helical fuel pump gear in the image above.

Unlike the cams, the pinion gear shaft does not come out of the case. The gear slides off the shaft and seats in a small keyway. The only stubborn part of the night was convincing the pinion gear to come off the shaft so I could replace the fuel pump gear.

From what I had heard, I expected the gear to look pretty hammered, but it still looked like new so we decided to keep it as a spare should we ever need to replace the new brass gear.

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I slathered the shaft and the inside of the gear up with assembly lube and replaced the old gear with the new one.

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The #1 and #3 cam need to be installed first before you can fit the #2 cam. There are alignment marks on all the cams to make sure you have the timing right. So it's important to make sure those marks all align before you continue.

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It's a little easier to see the alignment marks in this image. You are initially making a best guess as to where the marks will line up when you install #1 and #3, but you'll be able to make the alignment right when you add the #2 cam. I don't think it was part of the instructions, but it was much easier to get the cams in with the pinion gear removed. 

You need to make sure you're paying attention to where the alignment mark will match up and we turned the back wheel to get the pinion gear where it needed to be. The rear piston was at top dead center when the pinion gear was aligned properly.

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I wasn't afraid to use the assembly lube as you can see above. You can also see how the alignment marks all match up. As a double check, with four fingers in the lifter openings, we rotated the rear wheel to make sure they were moving as they should before we closed up the case.

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Although there is a tool to keep the cams from moving when you complete this next step, with Steve firmly depressing the rear brake, I torqued the pinion shaft nut (this torque value will be in your shop manual).

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Before replacing the cover and installing the new cover gasket, I scraped any of the old gasket off to make sure we had a clean surface so the new gasket would seat properly.

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There is a torque value and a tightening sequence for the cover bolts. I snugged them down in the sequence with a ratchet before I pulled out the torque wrench. I was careful not to tweak anything buy going around the pattern several times before I finished with the torque wrench. Unlike most of the other times I've needed a torque wrench, the torque values for these fasteners were in inch pounds rather than foot pounds. If you don't have both torque wrenches, I believe there is a formula for the conversion, but I have both varieties so I don't have to worry about the math.

I was surprised at how little torque was required, so would recommend using the torque wrench to avoid over-tightening these fasteners.

I really liked this part of the project. I think it's because of the straightforward nature of the job. This was not a difficult job at all with the Sportster engine on my Buell. It probably helps that there isn't a lot of outside pressure to get this done.

Tomorrow night's project will be to check the valve clearance and finish putting the top end back together.