Today I’m going to walk through the basics of replacing the valve cover gasket / head cover gasket and rubber mounts on a 1989 Yamaha FJ1200. This is a fairly straightforward procedure that can be completed in a few hours with common tools.
The Yamaha FJ1200 is an old motorcycle, manufactured between 1986 and 1995. It might be old, but a well cared for FJ1200 can run 100k miles and still get you home safe. These motors were built to last. Even the toughest motor is going to fail without proper lubrication though. Oil starvation is one of the most common reasons for engine failure, and an older motorcycle is prone to gasket failure as the years wear on those rubber parts. Gaskets become hard and brittle; rubber washers become crusty and flattened, failing to do their job. Weeping oil not only wears on your motor but poses a safety risk – any amount of oil dripping on the road is bad news when your rear tire hits it and loses traction.
The bike we’re working on today is nearing the 50k mark and was weeping (okay, leaking) oil when I bought it. The most common cause for oil leaks on the top end of a Yamaha FJ1200 are the head cover gasket (commonly called the valve cover gasket) and the rubber mounts where the head cover is bolted down. If you’re replacing the valve cover gasket, you want to replace the rubber mounts unless you are 100% certain they have already been replaced recently and are in top shape. The rubber mounts can fail for a few reasons: age/wear and tear will eventually cause them to harden and start weeping oil, and if the head cover bolts are tightened too much it can crush them, causing them to become flattened and unable to do their job.
Tools & Prep
Before getting started, lets look at the tools we need:
- Philips head screwdriver
- 8mm & 10mm socket wrench
- Hose clamp pliers / vise grip (something to clamp the fuel line)
- Needle nose pliers
- Disposable nitrile gloves
- Clean rags
- Engine grease (optional but useful)
Get your bike into a clean, dry, level space before beginning our project. We’ll be using the center stand so you want to ensure you’re not on an unstable surface and won’t have to move the bike for a while.
The following parts numbers are for a 19989 Yamaha FJ1200. If you have a different year, you can make sure you have the correct part numbers using the Yamaha Parts Finder.
Note that you will need eight (8) of the rubber mounts for the head cover bolts. You always want to replace them all at the same time.
|Part||Yamaha OEM Part #|
|Head Cover Gasket||36Y-11193-00-00|
|Cylinder Head Rubber Mount (x8)||2GH-1111G-00-00|
I strongly recommend using quality OEM replacement parts. Aftermarket parts can be okay, but they tend to be of lower quality and might fail sooner. You can get the parts you need through a local Yamaha dealer, an online dealer specializing in FJ1200′s like RPM or on eBay (just be careful what you order/who you order from).
Replacing the Valve Cover Gasket & Mounts
Okay, so I got all my parts and tools and my “workspace”. I’m still doing some spring cleaning so my shed is pretty disorganized right now, but we make do.
Here’s the basic rundown:
- Put the bike on the centerstand
- Remove the seat & gas tank
- Remove air scoops, disconnect breather, choke & throttle cables, spark plug wires
- Remove the head cover / valve cover
- Clean & replace the valve cover gasket
- Replace the head cover bolts & rubber mounts
- Conclusion, put everything back together!
Shazam. It’s an easy job if you don’t screw it up.
As always, store all removed bolts/parts in separate containers, in order, in groups! I usually keep a few metal dog bowls around and put all the parts in based on assembly – stuff that goes together belongs in the same dish.
1. Put the bike on the centerstand
Pretty straightforward. If you have any issues with this, which I did at first, read this.
2. Remove the seat & gas tank
Remove the seat, then undo the two bolts holding the gas tank down. Now you can lift up the gas tank and prop up the end with a block of wood, giving access to the fuel line coming from the bottom of the tank.
You can disconnect the wiring harness, and carefully pull the rubber breather hose up to free it from the bike. It’s not attached to anything, but attention to the routing.
Once the tank is up you can get to the fuel line (seen below). Place a rag to catch some fuel that will spill out when you disconnect the fuel lines. Clamp the fuel line off about 6″ above the connector leading to the carbs (closer to the engine, not the tank). I used a vice grip with some thick pads to prevent damage and it worked great.
Now loosen the fasteners where the fuel line connects, and slowly work the fuel line off the brass fitting. Disconnecting a fuel line can be hard, especially if it has been on for a long time. Instead of pulling directly on the line (which will actually tighten it), use a few small hooks or eyeglass screwdrivers to work the line off the fitting. Be careful not to gouge/scratch the fitting. Once you start to separate the fuel line from the fitting it will work its way off easier. Mine was stuck on tight! A quick disconnect would be a nice mod for this bike.
Once the fuel line is removed, you can lift the gas tank off the bike. Store it on a clean, flat surface with a towel beneath to prevent scratching, and prop it up with a wood block.
Now we have a nice clear view of that head cover! Woo baby, witness the effects of a long-term oil leak covering that head in grime:
3. Remove air scoops, disconnect breather, choke & throttle cables, spark plug wires
Now remove the air scoops from the side cowlings, and the plastic air ducts leading over the top of the head cover will come with them.
You will see a small breather hose / rubber tube running along with the bundle of cables for choke/throttle control. It connects to a small ventilation port behind the metal carb “wall” – the metal plate mounted in front of the carbs. Remove with needle nose pliers.
Now disconnect the choke cable from the carbs (seen in the pic above, running from the choke control in the dash back to the carbs). A single bolt on the carburetors frees the cable, then you can rotate and slide the end out of the carbs. Move the cable out of the way and be careful not to pinch it or get it dirty.
If you want some more space, you can also remove the inner plastic cowling “dash” on both sides, but it’s not required.
Now you want to disconnect the throttle cables. Pay close attention to how they are set up and where the cables are routed – take a picture for later reference if you want. It’s fairly easy to reinstall them but you don’t want to mix them up or your throttle control might run backwards.
The throttle cable connector assembly (the plastic rectangular box) can be opened with a few small screws.
Now you can pivot and slide the throttle cables out.
Move cable out of the way and save the assembly parts in a separate container. You don’t need to disconnect the throttle cables from the carbs – the head cover can be removed by gently pushing the throttle cables to the side.
Finally, disconnect the spark plug wires by pulling them directly away from the engine. Grasp them firmly at the base, and make sure the rubber boot comes along with each wire. There are four wires, marked 1-4, which is the firing sequence from Left to Right (1234).
4. Remove the head cover / valve cover
Now we have full access to the valve cover!
Take your 10mm socket wrench and carefully remove each of the eight (8) head cover bolts. Take your time and if a thread catches – back off! Stripping any of these bolts will become a major pain and require much more significant work.
Once removed, set the head cover bolts aside and you can slowly lift the head cover from the motor and lift it free. If it’s stuck on fast, try a rubber mallet and some gentle whacks to free it.
If the last owner used silicon gasket maker or other sealant, the valve cover could be stuck and require some work to remove. Be careful not to use a screwdriver or other instrument that could scratch or damage the surface. A gouge or scratch here will render the gasket ineffective and require resurfacing/sealing.
Once the head cover is removed, the camshafts & top end will be exposed. Cover it up immediately with a clean towel so no debris gets in the engine.
Now we can replace that old gasket!
5. Clean & replace the valve cover gasket
Next order of business is to get the old gasket off. I did this mostly by hand, with a small plastic scraper to help with the tough bits. At least 1/3 of the gasket was dried, hardened and extremely brittle and cracked off in pieces. Pretty surefire sign it needed replacement there.
Mostly peeling by hand…
Once the gasket was off, I gave the head cover a good scrub with a toothbrush, Simple Green & a garden hose.
Once cover is clean and dried, we can set the new gasket. I don’t recommend using gasket maker / sealant, it isn’t necessary and can get bits in the motor, and make it harder to replace in the future.
You might have to cut off a connector tab in the center of the new gasket:
Just used an Xacto knife and slowwww cuts:
I did use a small dab of grease along the mating surface of the new gasket in 4-5 places just to keep it in place while reinstalling. Just use enough to make it stick a bit, don’t slather it everywhere. Tiny dabs.
Once you are happy that the new gasket is installed and seated perfectly on the valve cover, you can install the head cover back on the motor! We’re getting there!
Now to deal with the head cover bolts.
6. Replace the head cover bolts & rubber mounts
Before we can install the head cover bolts, we need to put the new rubber mounts on the cover bolts. Before we can do that, you need to remove the old rubber mounts.
These old mounts are probably stiff and hard to remove by pulling them off. I carefully clamped each bolt and used a razor blade to cut off the old mount. This works great, but you want to be careful not to scratch the bolt, damage the threads or otherwise hurt anything, including yourself!
I made several passes each time and cut fully through the old rubber mount, then it pulled off the bolt with ease.
Now you should have eight (8) clean head cover bolts and new rubber mounts ready to go.
The rubber mounts should push on easily:
Now we can tighten the bolts down and secure the valve cover with our new gasket and rubber mounts.
Take heed: the next step may be the most important step of all steps.
The head cover bolts don’t require much torque. They “seat” themselves and if are tightened too much they will damage the rubber mounts at best; at worst, the bolt will split itself in half and you will wind up with a dangerous and terrible job of extracting a broken bolt from your top end!!
A torque wrench is not necessary. Although some might still recommend it, the tightening value is very low and you can feel the bolts “seat” themselves when tightening.
Replace each of the head cover bolts and hand-tighten them.
Now, before getting a wrench, visually inspect around the entire gasket and the rubber mounts to make sure everything is seated and aligned perfectly. If the gasket slipped out somewhere, you want to find out now – not once you have put everything back together!
When you’re ready to tighten the valve cover bolts, use a small 1/4″ socket wrench with a 10mm adapter. Tighten each bolt by hand until you feel the resistance suddenly increase. You will feel when the bolt “bottoms out” or “seats” and it will instantly become much harder to turn. At this point, I gave it a tiny snug, about 1/8th-1/16th of a turn and moved to the next bolt.
If you’re forcing the bolt, it’s too tight!
There, valve cover is back on and we’re ready to clean up and put everything back together!
Now you can reassemble everything more or less in reverse order.
Spark plug wires, throttle cables, choke, breather hose. Check your throttle action and return before replacing the gas tank. Replace the side air scoops. Now replace the gas tank, slip the breather hose back into the frame, connect the wiring harness, attach the fuel line, bolt the tank down. And of course make sure to remove the clamp from your fuel line.
Now replace the seat and when satisfied you can start that FJ1200 up. Immediately after starting the bike, keep a close eye on the motor, oil levels and at any sign of continued oil leaking, inspect your work.
If all went well, take the bike out for a short ride, inspect it again, then crack a fresh beer to celebrate.
Thanks for reading, and I hope this guide serves to be useful to another Yamaha FJ1200 owner who wants to handle some basic maintenance on their own. Please feel free to share any thoughts, suggestions, improvements or your own experiences in the comments below.