T100 Engine Covers

In my first two years riding my motorcycle I learned a few things the hard way. Long story short I laid my Thruxton down twice, once on each side. They weren’t bad spills but I got a few cool scars out of the deal and so did my bike.

A few weeks ago I purchased new T100 (chrome!) engine covers and today I’m fixing up the last of the damage left over from my wipe-outs. The alternator cover isn’t too bad but the primary got beat up something aweful. Here’s what my covers looked like before:

Removing Old Engine Covers

The first and most obvious step is draining your oil. The primary and alternator covers are wet seals and if you break them you’re gonna leak all of your oil out on to your driveway / garage floor. I’ve planned this maintenance around an oil change anyway so I drained my oil completely and have a new oil filter ready to go.

I started on my primary cover: removed the bolts and started to pull. This thing wasn’t budging so I broke out my rubber mallet. That’s right, when all else fails hit it with a hammer … but not one that will scratch up your new chrome parts! A few good taps around the seams and the seal gave and started dripping oil all over the place. Have a pan ready and set yourself up on some cardboard to catch any stray drips.

The cover should come off easy enough but the seal is likely to break up leaving bits stuck around the edges. You’ve got to get all of this off before you can put the new cover and seal on so break out a razor and carefully scrape what’s left of the old seal off the engine. Be very careful not to get little bits of the seal on any of your engine’s internals. You do not want little bits of plastic floating around gumming up the works.

When you’re done the mounting surface on the engine should look nice and clean. Here’s what the primary side looks like (forgot to shoot the alternator side):

Alternator Cover

On the alternator side you’ll notice some wires that run out from between the engine case and the cover. These connect to the stator and power your electrical. The seals around these are a bit of a pain. You’ll have to transfer the coils to you new cover then worry about the wires.

When you reattach the alternator cover you’ll have to get your new seal in place but that probably won’t be enough. The wires have a rubber housing that you should seal up too. I opted to “borrow” some Form-A Gasket Sealant from my room mate.

This stuff is nasty. Get ready to apply it with your fingers and then spend some time scrubbing it off your hands later. You want to put enough on to fill the cracks but if you put so much on that it oozes out. It’s probably oozing out inside the case too which is not a good thing.

When you’ putting the the cover back on you’ll wish you had a few extra hands. Holding the seal, the wires and the cover in place at the same time is a pain, especially with the seal goop getting on everything. Once you juggle it all into place torque down the bolts to the spec (9Nm if I remember correctly which isn’t much).

The sprocket cover is easy in comparison. No seals no nothing. Just throw it on. Here’s what they look like, nice and shiny:

Primary Cover

The primary side doesn’t have any wires for you to worry about but it’s more of a pain. First off if you’re bike is on it’s kick stand the primary side will be tilted toward the ground which will make putting the cover back on much more difficult. Specifically there are a few metal pins that are seated in the cover and they’ll slide out much more easily if the engine is tilted downward.

Pay attention to the small cog at the lower front of the engine on this side. There’s a funny washer sitting over the pin holding it in place. This pin has a corresponding hole it will fit into on the inside of the primary cover. If you’re not careful while the cover is off this washer and pin may slip out. Be very careful of this.

Also on the primary side is the clutch leaver that you’ll have to transfer from your old cover to the new one. These are held in place by 7 or 8 hex screws that Triumph was kind enough to goop up with red locktite. This makes removing them very difficult and you’ve got to be extra careful to keep from stripping them.

I’ll admit that I stripped one but managed to get it out still. I had to take a trip to the local fastener shop in Syracuse to get a replacement. As much as the locktite is a pain when you’re removing the bolts it’s a good idea to use some when you put them in your new cover. Having one of these come loose in your engine would pretty much be the end of it.

I probably don’t have to say this but when you do transfer the clutch leaver over keep an eye on the set-up in the old cover and make sure you get everything in place right. It’s not hard but I’m sure it can be screwed up if you’re not careful. Be sure to keep track of the pin seated in the case that actuates the clutch. Mine kept dropping out of place when I was putting the cover back on.

Speaking of putting the primary cover back on, it’s a pain in the ass! If you’ve got an extra set of hands around you’re gonna need them. Here’s what it should look like when you’re done.

Oil and a Paryer

So when both covers are back on with the seals in place and torqued down, finish your oil change (change your filter etc). It’s not uncommon for the seals to leak a little bit at first until their seated. If they keep leaking after you’ve had the engine running for a bit try tightening down the bolts a little more but not too much. If this doesn’t fix your leak then something more serious went wrong (damaged seal?).

If you were looking at the pictures closely you’ll notice there weren’t any pipes on my Thruxton. I timed changing the engine covers with sending my pipes out to a local guy who runs a paint booth / powder coating shop out of his garage. More to come on that.

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