I thought I'd post up how I do it. As far as adjusting valves go, I doubt they can be any easier than on a DR650.
First up, you need to remove the tank to gain access and then clean around the engine, the rocker covers, and importantly, to me, the frame and wiring above. This is because once the engine is open, and you are working there, its easy to dislodge some crud that can then fall inside the motor. I used a hose then compressed air to dry and move anything left on. Having previously assembled all the wiring harness connectors with dielectric grease gives confidence with this process.
I like to remove a spark plug when doing the valves, and its important to pay particular attention to around the plug lest anything fall in when it comes out. I've even had quartz chips wedged in there that I needed to chisel out before I could get the plug socket over the plug properly.
Pulling the outer plug after a basic scrub. Note the best use I've come up with for Golf tees, plugging the fuel lines.
The outer plug and valve covers have been removed.
On the stator cover is a 10 mm ratcheting spanner which works well when removing the valve/tappet covers.
Sitting on the head is a pair of bent feeler gauges from ProCycle, but no doubt available from other sources. You can also just bend up normal straight feelers. They need to be bent to comfortably get them in between the valve stem and tappet. The nice thing about the PC ones is that one does inlets and the other does exhausts using the go no go method.
What's the go no go method? Its when the thin one slides in, and the thick one doesn't. The spec for the DR is:
Inlet 0.08 - 0.13 mm
Exhaust 0.17 - 0.22 mm
The PC feelers are:
0.10 - 0.13
0.15 - 0.20
So when doing the inlets, if the 0.10 slides in and the 0.13 doesn't, or almost does, its all good and leave it alone. Likewise, with the exhaust, if the 0.15 slides in easily, and the 0.20 doesn't or almost does, its all good and nothing else to do but put it back together.
But I'm getting too far ahead. Gotta get TDCC, or Top Dead Centre Compression for best results first. You can do this by the book, and remove the bungs in the stator cover, which can be problematic, or do it my way.
First note that I have a 'porcupine' magnetic LED light stuck to the frame to put a bit more light on the exhausts.
Secondly, there is a plastic drinking straw down the plug hole. By putting the bike into 4th or 5th gear and turning the wheel to turn the engine over you can watch the straw rise and fall. It might need a little help too. Also watch the inlet valves. Once they close, ie the valves rise, and the straw tops out, then that's close enough to TDCC for doing the valves.
Above is a picture of a cam I found on the net. Valve clearance is set when the cam follower, in this case the rocker, is sitting somewhere on the base circle of the cam which is almost 3/4 of the rotation of the cam. This means that TDCC is not really essential, BUT, the DR650 has an exhaust valve decompressor. I'm not familiar with its specific operation, but I know that with my Bergs which also have a decomp on the exhaust, if its not at TDCC, then the decomp can give a false reading, so to make it simple, and take away any room for error, find TDCC.
Here is a pic with 2 lobes, and because of the different position, less room for error with TDCC, but as long as the drinking straw is more or less at the top, it'll be close enough.
Above its checking the inlets for go no go.
Checking the exhaust the same way the 0.15 just slid in, so a bit tight and needed loosening a bit.
Above I'm using a PC sourced adjustment tool. Its got 6 detents on the handle and I've drawn a line joining the opposites with a red marker. These are at 60 deg. I've also dotted one of the red lines and drawn another at 90 deg to the dotted one in black.
I pulled a tappet screw out and measured its pitch at 0.75, that's 0.75 threads to the mm. So with a little math, the ex clearances, 0.17 - 0.22 is 0.227 - 0.293 turns or 80 - 105 deg rotation. So backing off the lock nut a bit and then gently seating the tappet, then backing off 90 deg gives a suitable clearance. Holding the adjuster at 90 deg, spin the locknut down, then remove the adjuster and nip up the locknut. Check with the feelers if you feel the need and its done.
Similarly, the inlets are 0.08 - 0.13 which is 0.107 - 0.173 turns or 38 - 62 deg. A bit less than 60 deg that's marked on the tool and good to go too.
When you seat the tappet screw, make sure you've backed off the locknut enough so that you don't get a false reading. Also, gently seat it a couple of times to squeeze out any oil film that might also give a false reading.
So in 57,000 kms the inlets were loosened off a bit last time, and this time its the exhausts, so one adjustment each needed to date. Not bad at all, and about the same as my Bergs FWIW, although that's extrapolating out their life to date. My Courier diesel ute needed its first valve, and only one of twelve, adjusted at 260,000 kms.
Button it up and done.
But because I'm now at TDCC, I'll take advantage of that to pull and service the starter motor. Pics to come.