F800GS Valve Adjusting step by step.
I have a big trip coming up where I expect to put on over 30,000km. My bike currently has 34,xxxkm on it. Although my clearances on all 8 valves are within spec they are on the tight side. Since motorcycle valve-trains tend to tighten as they wear (discussed here: Shim under bucket) I will feel more comfortable adjusting the valves to at least the middle of the spec range if not to the loose end.
With the service manual loaded on my laptop I headed out to the garage to tackle this task. I've never set motorcycle (or any valves for that matter) that weren't rocker/tappet/jam-nut style so this was/is a learning experience for me.
I snapped a bunch of pics and will do my best to explain everything so hopefully others will gain a better understanding of how to do it as well. I'll skip all the removal of body panels, battery and airbox (if you can't figure that stuff out you probably shouldn't be poking around inside your motor anyway!).
*I'm currently doing a bunch of other things on the bike and it wasn't ridable when I started this so I didn't get a chance to clean it top to bottom first so there was a lot of spot cleaning to do as I went along. Definitely wash and degrease your bike as best you can before you start!*
*Tips from inmate NCD:
1. After you cut the zipties along the LHS to move the wiring: Pull the lower plastic plug out of the frame that serves as the anchor for the ziptie.
2. Unplug the RHS injector plug (buys you some more wire slack.) Strap that whole wiring mess off to the right while you are working.
3. After you unhook the throttle cable, do the same with the clutch cable. Curve them up and forward out of the way.
4. Cut the zipties and remove the 2 nuts that hold your seat latch in place. Unplug the small connector and hang the whole thing off to the left.
The time it takes to do this will save you time tenfold. It lets the valve cover come off without drama, and go back on without smudging the sealant. You can remove and reinstall the 3 lines at the back of the airbox without using every curse word in your vocabulary also.*
Valve cover off:
Rotate motor to TDC on #1 cylinder. There are marks on the cam sprockets which will point at each other in the middle between the two sprockets (not aligned in photo).
Slide feeler gauge between the cam lobe and the follower to measure the clearance. With the timing marks lined up you can do all 4 valves on cylinder one (left side of the bike).
Once you have number one cylinder measured, rotate the motor until the timing marks are now at the same height but pointed completely away from each other (sprockets 180 degrees from where they were previously). I know, clear as mud right? I'll snap some better pics of that tomorrow.
*edit: To rotate the cams 180 degrees you need to rotate the crank 360 degrees*
The intake clearance specs are 0.18mm-0.26mm
The exhaust clearance specs are 0.27mm-0.35mm
My intake clearances measured 0.19mm, 0.20mm, 0.19mm and 0.20mm
My exhaust clearances measured 0.28mm, 0.31mm, 0.31mm and 0.32mm
I'd like to loosen all the intakes to at least 0.22mm and the first exhaust 0.31 or 0.32mm.
Once you've measured the clearances on cylinder #2 you need to rotate the motor to #1 TDC again (timing marks pointing at each other in the middle again).
On the left side of the bike there is hex head bolt that also accepts a torks bit. It is located right behind the oil cooler lines.
Remove this bolt.
BMW has a special tool that you thread into this hole and it locks the crank in place to insure it doesn't move from TDC #1 cylinder while you perform your valve adjust. I don't have the BMW tool but made something similar by tapering an M8 allen head bolt with the bench grinder.
If you look in the hole with a flashlight (I wore my skull beam while doing the adjustment) you can see there is notch in the flywheel. The bolt engages this notch and locks the crank in position before you remove cams and timing chain tension.
Thread the bolt into the hole with LIGHT pressure until it bottoms out in the notch. I found the easiest way to rotate the motor for all these steps is to put it in gear and turn the rear tire (easier if you remove spark plugs first).
Homemade lock pin threaded in thus locking the crank at TDC #1:
Then you back off all the nuts holding the cam bearing plate on. It's best to back all the nuts off in stages before totally removing any of them to avoid twisting the bearing plate. Start with the center nut and work your way out. Once you have them all loose you can remove all of them and gently remove the cam bearing plate. Mine came out easily but you may need to pry yours up. If you do this make sure you use non-marring tools and be careful not to damage the soft aluminum bearing plate.
Once the plate is off you need to release the tension on the timing chain. On the back of the motor on the left side is the tensioner.
Remove the nut, sealing washer, spring and pin from the tensioner body. A dental pick (or similar) and a magnet are very helpful.
Work the timing chain off the cam sprocket of the intake cam and hang it on sprocket of the exhaust cam. Gently and carefully lift the intake cam out of the head and place it somewhere clean.
Lift the timing chain off the exhaust cam sprocket and secure it so it doesn't fall into the motor. I zip tied it to the frame. Remove the exhaust cam and place somewhere clean as well.
The cam followers are now exposed:
There are several openings in the motor that the valve shims can fall into. Mark sure to plug these holes with rags before going any farther. It's a good idea to have a telescopic magnet handy incase you do drop a shim (they are tiny).
It's important to know which shim came from which valve. I cut a small chunk of wood and drilled 8 shallow holes in it and marked intake and exhaust as well as numbered 1-4.
The shims reside in a pocket under the follower arm. It's easiest to get them out using a magnet.
As soon as you get them out put them in a suitable labeled container or tray. Once I had all 8 out I put tape over the tray so I wouldn't lose or mix up the shims.
This is how small the shims are (0.31" wide):
The shims have their thickness printed on the side of them. There was no way to get a pic of that. I could hardly see it. Tweezers and a small magnifying glass will be very helpful (seriously).
I took the shims out of their spot in the tray one at a time and recorded it's thickness before returning it to it's hole in the tray.
Now armed with a list of valve clearances and the thickness of the corresponding shims I sat down with the laptop (with Max BMW parts fiche page open), calculator and notebook and did the math.
I was pretty happy with 3 of the 4 exhaust valves but the other exhaust and all the intakes needed to be loosened up a bit.
It's pretty simple math. I won't go through all my valves but here's an example:
#1 exhaust valve clearance is 0.28mm with a 5.05mm shim.
I want the clearance to be between 0.31mm and 0.33mm, so I need the shim to be 0.03mm-0.05mm shorter than it is.
5.05mm - 0.03mm = 5.02mm or 5.05mm - 0.05mm = 5.00mm
Shims are available in 0.05mm intervals so I can't get a 5.02mm so I'll need to go with the 5.00mm shim which should give me a valve clearance of 0.33mm.
Some of the shims in the motor are in 0.025mm intervals but they aren't available to the general public. I suspect that the dealership service departments can get the in between sizes.
I got lucky on a couple of my shims. Since the 8 valves in the motor don't all have the same size shims, I was able to switch and swap a few around. In the example above I was able to use the shim from my #2 intake (which was a 5.00mm) and put it in the #1 exhaust position and get my desired clearance. My #4 intake shim was 4.975mm which was a perfect fit for my #2 intake spot. I had to adjust 5 valves but only had to buy 3 new shims.
Once you figure out what shims need to go where, you lightly oil them and stick them in the pocket under the cam follower. The shims are light enough that the small amount of oil on them basically suctions them in and they don't fall out when you flip the follower arms down on the valve stem.
-pull all your rags out of the holes in the head.
-reinstall the exhaust cam, cut the ziptie off the timing chain and hang it on the sprocket.
-reinstall the intake cam and work the timing chain over the sprocket,
ensure the cam timing marks are lined up.
-place the cam plate back in place.
-install the retaining nuts on the cam plate. Get them all started and finger tight then start in the middle of the plate and torque in stages until all are @ 10NM.
-reinstall the chain tensioner assembly.
-remove the crank lock bolt but do not replace it with original bolt yet.
-re-check the valve clearances starting with #1 @TDC then rotate 180 degrees and check #2 at TDC. If the clearances aren't what you wanted then you have to start over again. If the clearances are good replace the original bolt into the crank lock hole.
-re-install the valve cover
-re-install the coils
etc, etc, etc.
* I put this together at 3am so it's likely full of typos that I won't catch until tomorrow, apologies! *
Thanks for the detailed pictorial how to and adding to the knowledge pool :thumb
I've been waiting for this. You da man! Questions. Cost of shims? Does dealer trade them in? Any static from dealer? How much dirt went into your engine. (Just kidding on that last point.)
Awesome GNP. Awesome. You have more guts than I do!:beer
Awesome work, thanks for this! :bow :bow
Does BMW want you to use something like this for the cam retainer on the twins?
holy wow dude. Strong work.
There was a bit of dirt for sure. I spent a lot of time cleaning with rags and the shopvac. I hadn't really planned on doing all the bike projects at once but I had some down time and it just kind of worked out this way. I definitely suggest cleaning everything really well prior to tackling this one!
That is a great writeup........Nice....:thumb:thumb
:thumb Great job, thanks! Looks completely do-able if you take it slow and easy.
Awesome, I might actually do something about my valves now, thank you!
I've been most of the way in the top end while trying to fix the oil leak in Yukon, you've now taken me the rest of the way. :deal
Need a cameraman to film you guys on your SA trip?.... :norton
|Times are GMT -7. It's 01:04 AM.|
Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014