I just got the 32,000mi service wrapped up in my garage. Since this is the fourth time I've done this job on the CB1100, I've learned a few things along the way (usually the hard way) that ought be passed along to those doing their own service.
The Honda Service Manual is great, but to get started, it refers you to a prerequisite step, which refers you to another step, which refers you to another step, which refers you to yet another... it's maddening. I made a little sheet listing the steps as the manual presents them, but added little numbers on the left of each step in the order you actually need to do them (along with page numbers on the right). Now all I do is go (1) - (10). See the posted picture.
DO NOT take the cam chain tension off before turning the crank over by hand and measuring all the valve clearances as specified by the manual. Turning the engine over with no tension could cause you to skip a tooth on a cam sprocket, then you have to remove the cams even if all your valves are in spec. This is a redundant step anyway--it's listed later in the manual on in the cam removal process where it should be. Anyway, if you have no need to remove the cams because your valves are in spec, there is no need to do this step before taking measurements.
Next, I finally found the trick to getting the valve cover out of the frame without uttering dark oaths for 20min. It's the throttle cables and the main wire harness on the left frame tube that are making things difficult. A little pushing/nudging of the cables and harness while working the thing loose makes the job far easier. Be sure to put some duct or other thick tape on areas that interfere with the removal to avoid scratches.
Once the cover is off, locate the four tiny o-rings that go on the valve cover alignment dowels and take them off if they are not already on the floor. Leave these o-rings off until you have the cover back on later, then lift the cover a little and re-install them. If you try to install the cover with them on the dowels, they can (and will) fall into the engine! A bad thing, and huge waste of time to recover them so they don't clog an oil return passage or something worse.
There is no reason to remove the sprocket on the exhaust cam, ever. Leave it on. The intake sprocket has to come off to remove the cams because Honda didn't see fit to make the timing chain one link longer so the cams could come out whole after taking the chain tension off. Huh This leads to a lot of frustration when re-installing and trying to line everything up for proper timing. Anyway, you don't need to remove the exhaust sprocket.
Also, if the only valves that need adjusting are on the intake side, don't even remove the exhaust cam or loosen its holders. If the exhaust cam does have to come out, then both have to come out.
When reinstalling the cams, line up the exhaust cam timing mark "EX" first, then work on the intake side. Note there are 44 timing chain link PINS BETWEEN the "EX" and "IN" timing marks on the two sprockets when installed correctly. You can verify this before you pull the cams out. If you guess the position of the intake sprocket and then start to tighten things down in hopes of good alignment, you will guess wrong one tooth too far, then one tooth to close, about a dozen times. After you get the exhaust cam back in and lined up, you could even count off 44 pins and make #44 pin black with a marker so you can easily put the intake sprocket in correctly the first time. Don't worry, the ink will be long gone by the time you open the engine up again 8,000mi later.
Speaking of cam holders, they come off easy but during install you are invariably fighting a number of lobes pushing against valve springs, so you can't turn the bolts with your fingers and using a ratchet takes all day because of the tight work space and the gradual criss-cross pattern you have to use to avoid breaking something. Use a bit driver with a long extension and a swivel joint just above a six point 10mm socket. You can work from above the frame and have the holder bolts all tight in minutes. Be sure to final tighten with a small torque wrench.
Before putting the valve cover on, be sure to look at the cam lobes on cylinder 1 one more time to make sure the lobes are facing away from each other when #1 is TDC (compression stroke). See the second photo attached. It is possible to put a cam sprocket on 180 deg out of phase. Doing so will give the correct timing mark positions, but the bike wont run with both cams in exact phase (intake and exhaust valves opening and closing at the same time). I learned this on the 8,000mi service and got to remove EVERTHING a second time, including the cams, for extra credit.
Finally, the spark plugs are very easy to swap while everything is off the top end. It's a tight fit otherwise.
If I think of anything else, I'll post a reply to this thread.
Of note, four intake and two exhaust valves were at the loose end of the service limit so I put the next thicker size shim in all 6 to bring them back to the center of the range. It sounds like a precision instrument now--perfect.
Wrong head photo. I'll look for the correct one.
The Honda Service Manual is great, but to get started, it refers you to a prerequisite step, which refers you to another step, which refers you to another step, which refers you to yet another... it's maddening. I made a little sheet listing the steps as the manual presents them, but added little numbers on the left of each step in the order you actually need to do them (along with page numbers on the right). Now all I do is go (1) - (10). See the posted picture.
DO NOT take the cam chain tension off before turning the crank over by hand and measuring all the valve clearances as specified by the manual. Turning the engine over with no tension could cause you to skip a tooth on a cam sprocket, then you have to remove the cams even if all your valves are in spec. This is a redundant step anyway--it's listed later in the manual on in the cam removal process where it should be. Anyway, if you have no need to remove the cams because your valves are in spec, there is no need to do this step before taking measurements.
Next, I finally found the trick to getting the valve cover out of the frame without uttering dark oaths for 20min. It's the throttle cables and the main wire harness on the left frame tube that are making things difficult. A little pushing/nudging of the cables and harness while working the thing loose makes the job far easier. Be sure to put some duct or other thick tape on areas that interfere with the removal to avoid scratches.
Once the cover is off, locate the four tiny o-rings that go on the valve cover alignment dowels and take them off if they are not already on the floor. Leave these o-rings off until you have the cover back on later, then lift the cover a little and re-install them. If you try to install the cover with them on the dowels, they can (and will) fall into the engine! A bad thing, and huge waste of time to recover them so they don't clog an oil return passage or something worse.
There is no reason to remove the sprocket on the exhaust cam, ever. Leave it on. The intake sprocket has to come off to remove the cams because Honda didn't see fit to make the timing chain one link longer so the cams could come out whole after taking the chain tension off. Huh This leads to a lot of frustration when re-installing and trying to line everything up for proper timing. Anyway, you don't need to remove the exhaust sprocket.
Also, if the only valves that need adjusting are on the intake side, don't even remove the exhaust cam or loosen its holders. If the exhaust cam does have to come out, then both have to come out.
When reinstalling the cams, line up the exhaust cam timing mark "EX" first, then work on the intake side. Note there are 44 timing chain link PINS BETWEEN the "EX" and "IN" timing marks on the two sprockets when installed correctly. You can verify this before you pull the cams out. If you guess the position of the intake sprocket and then start to tighten things down in hopes of good alignment, you will guess wrong one tooth too far, then one tooth to close, about a dozen times. After you get the exhaust cam back in and lined up, you could even count off 44 pins and make #44 pin black with a marker so you can easily put the intake sprocket in correctly the first time. Don't worry, the ink will be long gone by the time you open the engine up again 8,000mi later.
Speaking of cam holders, they come off easy but during install you are invariably fighting a number of lobes pushing against valve springs, so you can't turn the bolts with your fingers and using a ratchet takes all day because of the tight work space and the gradual criss-cross pattern you have to use to avoid breaking something. Use a bit driver with a long extension and a swivel joint just above a six point 10mm socket. You can work from above the frame and have the holder bolts all tight in minutes. Be sure to final tighten with a small torque wrench.
Before putting the valve cover on, be sure to look at the cam lobes on cylinder 1 one more time to make sure the lobes are facing away from each other when #1 is TDC (compression stroke). See the second photo attached. It is possible to put a cam sprocket on 180 deg out of phase. Doing so will give the correct timing mark positions, but the bike wont run with both cams in exact phase (intake and exhaust valves opening and closing at the same time). I learned this on the 8,000mi service and got to remove EVERTHING a second time, including the cams, for extra credit.
Finally, the spark plugs are very easy to swap while everything is off the top end. It's a tight fit otherwise.
If I think of anything else, I'll post a reply to this thread.
Of note, four intake and two exhaust valves were at the loose end of the service limit so I put the next thicker size shim in all 6 to bring them back to the center of the range. It sounds like a precision instrument now--perfect.
Wrong head photo. I'll look for the correct one.