Tips and Tricks for Checking and Re-Shimming FJR Valve Clearance
Posted: Fri Sep 11, 2020 7:39 pm
Tips and Tricks I’ve Learned Regarding Valve Checking and Re-Shimming on the FJR
These tips are given in sequence of how the job is done. This is not meant to be a substitute for following the Service Manual. But rather, some things that I’ve learned along the way that will help the inexperienced person.
1. Parts and materials you will DEFINITELY need:
a. Cooling pipe O-rings (2 each)
b. High-temp RTV gasket maker
c. Coolant drain bolt brass washer
d. Pre-mixed coolant (3 quarts)
e. Di-electric grease (small packet)
f. 10” piece of 2 x 4 lumber.
g. 1” wide stiff putty knife
2. Parts and materials you MIGHT need:
a. Timing cover gasket
b. Spark plugs – Note – you might as well change the plugs every time you go through this.
3. Check your valves with a low amount of fuel in the tank. It’s easier to handle it 45 pounds lighter.
4. After removing the heat shield, T-Bar, and PAIR system, use a permanent marker to label the cylinder numbers for each coil/spark plug boot.
5. The coil/boots will be “stuck” into the cam cover if this is the first time you are removing them. First, rotate them back and forth, then gently wiggle them a little to loosen. Then, use your putty knife to gently pry the boot against the cam cover. On re-assembly, put a film of di-electric grease on the boot mating surface and you won’t have the problem again.
6. If you have a shop vac, rig up a small (1/4”) plastic tubing to your hose. You can use this small hose to suck up all of the little pebbles/grit/dirt that has found its way into the cracks and crevices of the cam cover (spark plug holes, cooling pipe recess, etc). You are about to open the motor – let’s keep things as clean as possible.
7. Don’t be surprised of the allen socket bolts for the cooling pipe are slightly rusted. For this, make sure that your allen socket (better than a wrench) is new and decent quality for a tight fit. When you loosen these bolts, push slightly down on the socket (compresses the o-ring to make it easy to loosen), and concentrate on not allowing the tool to get off center. Obviously, if you round off this fastener, it’s going to be a total PITA to deal with.
8. For removing the coolant hose (coming from the thermostat), use an 8mm ¼” drive socket and rachet. After the cooling pipe is removed, rotate the hose clamp 180 degrees. This will make re-assembly easier, and from now on, you won’t have to be a contortionists to get to that clamp.
9. Remove the screws that hold the hardware brackets for the throttle cables at the throttle bodies. You don’t have to remove the cables at the engine side. However, at the throttle (handlebar), physically remove the cables from the throttle tube. This will allow enough slack to get the cables out of the way for the cam cover. Trust me – if you don’t do this, you will be cursing at it later.
10. After the cam cover is removed, take some paper towel pieces or rags pieces and cover ALL holes in the engine (coolant passages, oil passages, spark plug holes, etc). You don’t want anything falling in there.
11. BEFORE you do anything further, take your cam cover to your bench. Remove the rubber gasket and thoroughly clean/dry both the gasket and the gasket mating surface with some carb spray or similar. Take your High Temp RTV and put a small dab of it in several places along the mating surfaces. Make sure that you put a dab at each of the “corners” where the gasket goes from straight to the “circle” part. The idea here is to use the RTV to “glue" the gasket to the cam cover and let it dry/cure for a few hours before you re-install it. You will use that time to check and/or shim your engine valve clearance. If you don’t do this, then the gasket is going to separate from the cam cover while trying to install it and it is going to drive you nuts. You don’t have enough room to “hold” the gasket in place while you install the cover.
Now – the next tip requires you to make an assumption. If you look at the profile of any camshaft lobe, I believe that half of the lobe is a perfect semi-circle. That semi circle represents the time when the valve is completely closed. This is the time in the revolution when you check the valve clearance. My assumption is that you should be able to check the clearance anywhere within that rotation of the semi circle, and the reading should be the same.
12. You do NOT have to remove the timing cover to simply check the valves. Put the motorcycle in top (5th or 6th) gear. Then simply rotate the rear wheel until the cylinder/cam you are checking has fallen anywhere within the semi-circle part of the lobes. Recognize that the motor might not be in perfect time for that cylinder when you check it, but it won’t matter as the distance (clearance) between the cam and the bucket won’t change as long as you are checking it along the semi-circle.
13. Use ONLY “Go/NO-GO” feeler gauges to check valve clearance. I’ve struggled along the years with the subjective part of checking clearance. Is it a “tight 7” or a “loose 6”? Then I talked with a Yamaha tech (25+ years in the business at that time) and he set my mind at ease. He said that the range of acceptable clearance is given for a reason. Yamaha designed the motor such that if you are at the end of the range, but still within it, then you can go another full maintenance interval without damaging the motor. So use the go/no-go feelers and if it “GOES”, then it’s good.
14. Now – if you find one or more outside of the range, then plan to re-shim as many as you can toward the loosest end of the range. The consensus of opinion is that the valve guide seat is the variable. Either with a carbon deposit, and or wear from repetitive banging, the valve guide seat is where the change in clearance will occur. As the guide seat wears, the clearance should get tighter. So if you adjust to the loosest end of the range (perhaps the loosest 30%), then theoretically, you should get more mileage for your adjustment. The most commonly needed shim for adjustment is 1.85 mm, 1.80 mm, 1.75 mm, and 1.70 mm. You really won't know what you need until you find out what you have, but if you want to take a stab in the dark at having the shims you will most likely need before you start the job, that is my best guess (perhaps 3-5 of each).
15. If it turns out that you need to re-shim the valve clearance, you do not have to remove the camshafts. Instead, simply put the #1 cylinder on TDC, then zip tie both cams to the chain (2 places each), zip tie the crank to the chain (2 places), then loosen the Cam Chain Tensioner, then simply move each camshaft (one at a time) to the side to get access to the shims.
16. Have a telescoping magnet ready to catch the cover bolt for the cam chain tensioner when you remove it. Otherwise, it will fall into the black hole of the motorcycle frame. Be sure to take some painters tape or duct tape and cover up the frame hole after you have loosened the cam chain tensioner. It's amazing how things just find the black hole to fall into.
17. Grind down a long skinny screwdriver to make the width of the blade more narrow. This is to make releasing the cam chain tension easier.
18. You can use a micrometer or dial caliper to calculate the math in order to find the best shim to get you to the loosest part of the range. However, in all the times I’ve done this, I have NEVER been able to go more than 0.05 mm down or up and still stay within the acceptable range. In other words, if you have 1.80 mm shim in the hole, and you need to loosen up the clearance, then a 1.75 mm will work, but a 1.70 mm will be too loose.
19. Don’t forget to remove your paper towels or rags from the holes BEFORE you re-install the cam cover.
20. Use the 2x4 lumber to prop up the fuel tank. After you put everything back together, without the heat shield installed, start the bike and run it up to cycle the coolant fans at least once. Then shut it off and with the tank propped, you can check everything for leaks before you cover everything up.
21. You will need a long neck funnel to fill the coolant. Fill it slowly and in stages to allow as much air as possible to burp out of the radiator neck. After you run the motor, and allow it to cool, you will still need to add a couple of mouthfuls of coolant to top it off.
These tips are given in sequence of how the job is done. This is not meant to be a substitute for following the Service Manual. But rather, some things that I’ve learned along the way that will help the inexperienced person.
1. Parts and materials you will DEFINITELY need:
a. Cooling pipe O-rings (2 each)
b. High-temp RTV gasket maker
c. Coolant drain bolt brass washer
d. Pre-mixed coolant (3 quarts)
e. Di-electric grease (small packet)
f. 10” piece of 2 x 4 lumber.
g. 1” wide stiff putty knife
2. Parts and materials you MIGHT need:
a. Timing cover gasket
b. Spark plugs – Note – you might as well change the plugs every time you go through this.
3. Check your valves with a low amount of fuel in the tank. It’s easier to handle it 45 pounds lighter.
4. After removing the heat shield, T-Bar, and PAIR system, use a permanent marker to label the cylinder numbers for each coil/spark plug boot.
5. The coil/boots will be “stuck” into the cam cover if this is the first time you are removing them. First, rotate them back and forth, then gently wiggle them a little to loosen. Then, use your putty knife to gently pry the boot against the cam cover. On re-assembly, put a film of di-electric grease on the boot mating surface and you won’t have the problem again.
6. If you have a shop vac, rig up a small (1/4”) plastic tubing to your hose. You can use this small hose to suck up all of the little pebbles/grit/dirt that has found its way into the cracks and crevices of the cam cover (spark plug holes, cooling pipe recess, etc). You are about to open the motor – let’s keep things as clean as possible.
7. Don’t be surprised of the allen socket bolts for the cooling pipe are slightly rusted. For this, make sure that your allen socket (better than a wrench) is new and decent quality for a tight fit. When you loosen these bolts, push slightly down on the socket (compresses the o-ring to make it easy to loosen), and concentrate on not allowing the tool to get off center. Obviously, if you round off this fastener, it’s going to be a total PITA to deal with.
8. For removing the coolant hose (coming from the thermostat), use an 8mm ¼” drive socket and rachet. After the cooling pipe is removed, rotate the hose clamp 180 degrees. This will make re-assembly easier, and from now on, you won’t have to be a contortionists to get to that clamp.
9. Remove the screws that hold the hardware brackets for the throttle cables at the throttle bodies. You don’t have to remove the cables at the engine side. However, at the throttle (handlebar), physically remove the cables from the throttle tube. This will allow enough slack to get the cables out of the way for the cam cover. Trust me – if you don’t do this, you will be cursing at it later.
10. After the cam cover is removed, take some paper towel pieces or rags pieces and cover ALL holes in the engine (coolant passages, oil passages, spark plug holes, etc). You don’t want anything falling in there.
11. BEFORE you do anything further, take your cam cover to your bench. Remove the rubber gasket and thoroughly clean/dry both the gasket and the gasket mating surface with some carb spray or similar. Take your High Temp RTV and put a small dab of it in several places along the mating surfaces. Make sure that you put a dab at each of the “corners” where the gasket goes from straight to the “circle” part. The idea here is to use the RTV to “glue" the gasket to the cam cover and let it dry/cure for a few hours before you re-install it. You will use that time to check and/or shim your engine valve clearance. If you don’t do this, then the gasket is going to separate from the cam cover while trying to install it and it is going to drive you nuts. You don’t have enough room to “hold” the gasket in place while you install the cover.
Now – the next tip requires you to make an assumption. If you look at the profile of any camshaft lobe, I believe that half of the lobe is a perfect semi-circle. That semi circle represents the time when the valve is completely closed. This is the time in the revolution when you check the valve clearance. My assumption is that you should be able to check the clearance anywhere within that rotation of the semi circle, and the reading should be the same.
12. You do NOT have to remove the timing cover to simply check the valves. Put the motorcycle in top (5th or 6th) gear. Then simply rotate the rear wheel until the cylinder/cam you are checking has fallen anywhere within the semi-circle part of the lobes. Recognize that the motor might not be in perfect time for that cylinder when you check it, but it won’t matter as the distance (clearance) between the cam and the bucket won’t change as long as you are checking it along the semi-circle.
13. Use ONLY “Go/NO-GO” feeler gauges to check valve clearance. I’ve struggled along the years with the subjective part of checking clearance. Is it a “tight 7” or a “loose 6”? Then I talked with a Yamaha tech (25+ years in the business at that time) and he set my mind at ease. He said that the range of acceptable clearance is given for a reason. Yamaha designed the motor such that if you are at the end of the range, but still within it, then you can go another full maintenance interval without damaging the motor. So use the go/no-go feelers and if it “GOES”, then it’s good.
14. Now – if you find one or more outside of the range, then plan to re-shim as many as you can toward the loosest end of the range. The consensus of opinion is that the valve guide seat is the variable. Either with a carbon deposit, and or wear from repetitive banging, the valve guide seat is where the change in clearance will occur. As the guide seat wears, the clearance should get tighter. So if you adjust to the loosest end of the range (perhaps the loosest 30%), then theoretically, you should get more mileage for your adjustment. The most commonly needed shim for adjustment is 1.85 mm, 1.80 mm, 1.75 mm, and 1.70 mm. You really won't know what you need until you find out what you have, but if you want to take a stab in the dark at having the shims you will most likely need before you start the job, that is my best guess (perhaps 3-5 of each).
15. If it turns out that you need to re-shim the valve clearance, you do not have to remove the camshafts. Instead, simply put the #1 cylinder on TDC, then zip tie both cams to the chain (2 places each), zip tie the crank to the chain (2 places), then loosen the Cam Chain Tensioner, then simply move each camshaft (one at a time) to the side to get access to the shims.
16. Have a telescoping magnet ready to catch the cover bolt for the cam chain tensioner when you remove it. Otherwise, it will fall into the black hole of the motorcycle frame. Be sure to take some painters tape or duct tape and cover up the frame hole after you have loosened the cam chain tensioner. It's amazing how things just find the black hole to fall into.
17. Grind down a long skinny screwdriver to make the width of the blade more narrow. This is to make releasing the cam chain tension easier.
18. You can use a micrometer or dial caliper to calculate the math in order to find the best shim to get you to the loosest part of the range. However, in all the times I’ve done this, I have NEVER been able to go more than 0.05 mm down or up and still stay within the acceptable range. In other words, if you have 1.80 mm shim in the hole, and you need to loosen up the clearance, then a 1.75 mm will work, but a 1.70 mm will be too loose.
19. Don’t forget to remove your paper towels or rags from the holes BEFORE you re-install the cam cover.
20. Use the 2x4 lumber to prop up the fuel tank. After you put everything back together, without the heat shield installed, start the bike and run it up to cycle the coolant fans at least once. Then shut it off and with the tank propped, you can check everything for leaks before you cover everything up.
21. You will need a long neck funnel to fill the coolant. Fill it slowly and in stages to allow as much air as possible to burp out of the radiator neck. After you run the motor, and allow it to cool, you will still need to add a couple of mouthfuls of coolant to top it off.
