Routine Maint. Valve Check

Inspired by CycleRob, this section is devoted to all flavors of the F800.

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Boxer
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Routine Maint. Valve Check

Post by Boxer »

This will have been the third time I've had Lil Chubb dressed down to the valve cover. Quite a task too. Plastic side panels and middle panel removed, front beak removed, battery removed, airbox removed, various connections and zip ties removed, throttle cable detached, and let's see...what else? That entailed what seemed like a dozen or so screws and nuts taken off and stored in various places around the shop and with the parts that came off.

Finally! Down to the valve cover!
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The valve cover itself is bolted down with four bolts that have metal and rubber washers and only go on with 10NM of torque. They were easy to take out. The trick is actually removing the cover once it is unbolted. Its like working one of those little wooden and rope puzzles that are impossible to do. There is only ONE way this thing comes out between the frame members and other obstacles, and it always takes me about 20 or 30 minutes to figure it out. When I do, I always say, "Damn! How come that was so hard?"

I have about three sets of automotive feeler gauges and to do this I think I had all the ones within the range of the valve lash specs, plus the smaller ones, laid out to use. Intake specs are between .18mm and .26mm. Exhaust specs are between .27mm and .35mm
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I got cylinder one valves closed and measured those first. Still pretty much the same as when I checked it last time: Intake at .23mm for both and exhaust at .31 and .32 (left and right) When I got the engine rotated so that the cylinder two valves were closed I got different readings on cylinder two: Intake was still .23 and .22 (left and right) but exhaust felt tight! I managed to come up with a reading of .29 and .28 (left and right) after rotating the engine a second time to make sure I was at the good spot. This alarmed me somewhat so I came inside and called Cyclerob. I needed him to help me interpret my data.

Rob cited a phenomena with Hondas from his days wrenching on them, where the cam bearing would wear on high mileage bikes and require the use of a special took to pry the cam upward slightly to take a valve lash reading. This, in essence, would give a more "real" spacer reading. He suggested I use a screwdriver or something and pry up on the cam a little to take a reading. Due to the spacing it was inpossible to get any kind of leverage on the intake cam, but I managed to get a small pry bar under the exhaust cam and put some upward pressure on it. Not much! I was afraid of pulling up too hard. I just needed to take up any tiny amount of play in the bearing. Indeed I got a second reading of .31 and .30 (left and right)...what is that? 3/100 of a mm difference? Not enough to worry about, in my estimation.

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Well, after I went out and did that, I came inside and Rob had called back and left a message that I didn't need to do that. That BMW had provided something to account for the cam bearing play. Rob can chime in here and explain that if he wants to. I just knew it really was not necessary now and the first reading was my true reading. It means that next time I check I will probably need to replace the tiny adjustment shims.

Once I was happy that all was okay for a while longer I cleaned the gaskets well with brake cleaner, reinserted the outer gasket into the cover, put some RED RTV on the areas around the round extended sections of the gasket and very carefully slid the cover back in place, making sure the tiny round rubber seal/gasket on the right side did not get disturbed or kinked as the cover moved down in place beside it. I like to use red RTV so I can see where it is when it come oozing out. I cranked it down until the bolts bottomed out and let it set up for a while, then put the required 10nm of torque on them. The reason I use the RTV is, number one, it is recommended, and number two, after the first time I took the cover off and replaced it, I had oil weeping out at those locations before the next valve check time. Now I don't have that happen.

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The whole thing is buttoned up now and today I will slowly and carefully replace all those parts, screws, bolts, zipties, etc. cleaning things up as I go.
I hope this helps anyone who is pondering doing a valve check on this engine. The hardest part, by far, is getting that damn cover out of place after it was unbolted. Remember! There is only ONE way it is coming out. Slide it toward the front, left up on the back and move it straight back and up almost without turning it at all.

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CycleRob
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Re: Routine Maint. Valve Check

Post by CycleRob »

Wow, 3 valve clearance checks so far . . . . you've been ride'n! I am approaching my 2nd valve clearance check when next summer begins.

About the Honda Sabre/Magna V-45 & V-65 (750cc and 1100cc engines) special camshaft lifting tool for a valve clearance check, it was necessary because those engines had a cam bearing wear problem. The cam sprockets were in the middle of the camshafts. It was near impossible to access both cam chain tensioners to release the cam chain tension that could hold the shaft down on the cylinder opposite its' neighbor that may not have enough "held open" valve spring pressure pushing back the tight chain's hold down. In the case of the F800 Rotax twins, there are massively wide well oiled bearings and the cam chain sprockets are on the left end, making them less able to mess up either cylinders' actual running clearances. Also, like every shim-n-bucket valve train assembly there is a range of acceptable clearances that are OK until that range is exceeded. The Rotax engineers must have taken those valve spring and cam chain forces into account (after Beta testing) when choosing the valve clearances. The Honda V-Fours threaded adjusters had one specific smaller numeric setting.

Here are some informative pics I took at my 12K mile valve clearance check, where they were all well within tolerance. The first 3 pics below confirm my fascination with the innovative centrifugal oil mist separating system, brilliantly incorporating 3 radial passageways into the existing water pump's black plastic drive gear. That innovative system has no extra parts like the usual/conventional/sizeable/heavier internal chambers, filter screens, covers, gaskets and bolts that were needed to completely exclude oil from the old style crankcase breather systems. With the F800 engines that means the crankcase vapors need too enter the 3 outer circumferential passageway openings of the spinning gear and loose the heavier oil mist liquid particles via centrifugal force while the practically weightless air travels the opposite direction toward the center of the shaft, to the valve cover receiver surface then the hose to the clean side of the air box chamber. That plastic centrifugal separator system saves weight, unnecessary cost and it works excellent when the engine is running, which BTW is the only time its needed. Those Rotax (BMW?) engineers are really brilliant.
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Now the feeler gauges needed to perform that valve check.

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Remember . . . cleanliness is vital to prevent gritty oil from quickly wearing away highly pressured critical sliding surfaces on engine start, like the cam lobe and rocker arm follower pad surfaces. When you are done measuring, squirt clean oil on the cam lobe wear surfaces to keep them alive until well after the engine starts. On the reassembly I used a thin film of the black version of the same Permatex High Temp RTV gasket maker on both sides of the entire gasket sealing surfaces to obtain a 100% weep free seal.

EDIT: To change photo provider and add text enhancements.
Last edited by CycleRob on Sat Jul 06, 2019 3:09 pm, edited 1 time in total.
`09 F800ST

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Re: Routine Maint. Valve Check

Post by RBrider »

Thanks, Boxer and CR. Very informative.

RB
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sweatmark
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Re: Routine Maint. Valve Check

Post by sweatmark »

Ditto, thanks guys. Mrs Sweatmark's F800 might reach 1st valve check by next winter if I twist her arm to ride more... Or I will have to ride it myself. Love that BMW/Rotax drivetrain.

Gotta ask you, Rob: after a career working with moto motors, what's you favorite engine and why?
Now: Rockster2, S1000R, K1300S
Then: R850R, R1100R, R1150R, Rockster1, R1200C, F800S, etc.
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Re: Routine Maint. Valve Check

Post by CycleRob »

"after a career working with moto motors, what's you favorite engine and why?"

Number 1 - - A water cooled 90 degree DOHC V-Twin with EFI, like the standard 2005 Suzuki SV-650 or SV-1000. Even the almost ancient carburatted V-Twins like the Honda VTR-1000 and 1,000cc RC-51, except for their unusually thirsty 32 MPG appetite, were really great street bikes. Need proof? See what Cycle World said in the "Why it Won" section: https://www.cycleworld.com/2010/06/01/b ... uper-hawk/. Not coincidentally, they all had aftermarket exhaust cans or full racing systems that so wonderfully connected the charismatic experience of these torquey motors, at any RPM, with even the smallest of throttle changes. This class also includes a regular customer's unforgettable, amazing, expensive 2 wheel masterpiece I rode to scuff in the new tires installed at the time . . . A Red Ducati 916 where the stock mufflers exited under the seat above the license plate. Check it out here: https://en.wikipedia.org/wiki/Ducati_916 To see the beautiful leg tuck-in curves of the fuel tank, bodywork and the short 4" long rearward pivoting brake pedal, see this pic: https://upload.wikimedia.org/wikipedia/ ... ati916.jpg

Number 2 - - The only 4 cylinder engine with a soul, a `94---`97 VFR-750F (with gear driven DOHC) without linked brakes!. With a slip-on can they had an exhaust sound that mimics a NASCAR V-8 engine, but with the 4 straight cut camshaft gear's drive whine like a Porsche 911. Sweet! It had a single sided swingarm and an engine with legendary durability and reliability. While on the topic of valve adjustments, the VFR-750 "shop manual only" 4 camshaft removal and installation for valve shim changes, was oddly satisfying, but definitely not for the average "wrench" (possible for $$$ damage!). It was also a great sport touring street bike when compared to the more extreme, racetrack focused SportBikes it competed with. Here's some dude's informative 22 minute ride on one (watch it all), Full screen and speakers On Loud: https://www.youtube.com/watch?v=i_L__y8DVn0

I think BMW should have made the F800 series engine with a 270 degree crankshaft, like the new Yamaha FZ-07, and a gear driven counter-balancer attached to a small, external bolt-on, excited field car type alternator. Yes it would have been more expensive, but there would NOT be so many fried/failed stator assemblies as has been happening with driving light equipped, high RPM riders -and- the bolt on external alternator would easily have at least 500 Watts of stronger, better regulated RELIABLE power. The exhaust note would sound great and the better inherently balanced 270 deg crankshaft engine would be easier to counterbalance if needed. For some stubborn reason BMW seems to be hung up on even firing twins. In a parallel twin engine a 270 degree crank sounds exactly like a 90 degree V-Twin and has less vibration than either a 180 or 360 degree crank. Triumph motorcycle has a few newer generation 2 cylinder parallel twin engines with 270 degree cranks and counter balancer shafts.
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Biff's R
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Re: Routine Maint. Valve Check

Post by Biff's R »

Thanks guys! This may be on my February to do list. It's just a pain in the butt, compared to the 1150R, to get all of the stuff off to get to the valve cover.
Jeff (lifer #289)
'17 F800GSA
'04 R1150R
There ain't no education in the second kick of a mule!
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