Maintenance

Valves!

/ 650thumper / 1 Comment

img_0476

Last autumn when my bike was having trouble starting in the cold, I took it to BMW for a check-up. It was my first experience servicing the bike. When I explained the symptoms and said the mileage was 38,000 km., the response was, “So you’ve got your 40,000 km. tune-up coming. It’s probably the valves.”

Valves. Those things that let fuel in to and exhaust out of the combustion chamber. The very word sends shivers down the spine of most. We associate valves with $. Whatever the problem is with the valves—and I had no idea at the time what could be wrong with mine—we just know it’s going to  be expensive. Just to get at the damn things you have to rip half the engine apart. When I innocently inquired what the 40,000 km. tune-up would cost, I was told $500. I gulped. My mind is not so capable in math as it once was, but I immediately recognized that sum as about 1/10 the value of my bike! So this is the infamous BMW service costs, huh? My second mathematical thought was “I’ve got 2000 km. to figure out how to do it myself.”

So I hit the internet over the winter months and relied on my trusty Chain Gang to point me in the right direction. What I discovered is that when people say “valves,” what they mean is “valve clearances.” That’s the space between the valves and the cams that open and close the valves. Over time and use, these clearances either shrink or grow, and the valves go “out of spec,” meaning they are outside a recommended range. If the intake clearance is too big, the valve might not be completely closing upon combustion, or if it’s too small, the valve might not be letting in enough air-fuel mixture. Similarly, if the exhaust valves are out of spec, the chamber might not be sealing or exhausting completely, and the engine just doesn’t run right.

You adjust clearances on my bike by swapping out tiny shims located under the “follower,” a metal cup that rests on top of the valve. It’s actually the space between the follower and the cam we are adjusting, but we adjust it by either raising or lowering the follower by adding a bigger or smaller shim underneath. We are talking hundredths of a millimetre (.05 mm) here, so you need a good set of feeler gauges. A good calliper is also handy for checking the actual size of the shim you are removing.

If you find this rather boring, all you need to know for added dramatic tension is that if you mess up this job you can do some serious damage to your engine. That’s right: you have to put your engine at TDC (top dead centre) and remove the cams to get at the valves, and if you put the cams back even slightly wrong, you’re going to hear a great gnashing of metal when you try to start the engine again, which is the sound of your valves getting destroyed. So I wanted to get this right. No wonder it’s $500 just to check them!

On my bike, there are a few things I had to remove to get to the valves:

  1. all the faring
  2. the battery
  3. the upper oil tank
  4. the air filter housing
  5. the throttle cable
  6. the throttle body
  7. the starter relay
  8. the electrical tray cover
  9. the battery tray
  10. the heat shield
  11. the ignition coils
  12. the coolant reservoir
  13. the coil holder
  14. and then, ta-da! the valve cover

Now I was able to check the clearances and, as expected, one intake and one exhaust valve (there are two of each) were out of spec. I had mixed feelings about this. Part of me was secretly hoping they were all good and I would avoid having to remove the cams, but part of me was hoping I would find the source of my problem. Now at least I knew I had to pull the cams.

Next I had to do the maths and here’s a confession: before I became an English scholar, I failed out of Maths at U of T. Okay, I didn’t really fail out; I just realized at mid-term I was not going to excel in this field so did the Honourable Disappearance. This wasn’t linear algebra, but you do have to have a head for numbers and some spacial reasoning (e.g. If my clearance is 0.16 and my shim is 2.85 mm thick, how big a shim do I need to get roughly 0.07 mm clearance? Sometimes in life, you really do need to find x!).  For my bike, the specifications for the intake valve clearance are 0.03 to 0.11 mm. So I figured the ideal clearance would be halfway between the two, or 0.07. For the exhaust, the clearance has to be between 0.25 and 0.33 mm. I sharpened a pencil and got to work.

With the calculations done, the cams off, the shims out, I headed off to BMW to get my new shims. I showed the dude the sizes I need. “C’est quoi ça?” he asked. Apparently I had used a standard calliper to measure the thickness of the shims, so was working partly in metric and partly in imperial and the whole thing didn’t make sense. Doh! Like I said: mid-terms only.

Fortunately, because I’ve spent enough of my life doubling back and forth from home to auto parts stores, I had the foresight to bring the shims and my calculations, so the nice gentleman borrowed a calliper from service and measured them for me, redid my maths, and sold me the shims. By this time it was getting late and I had to be somewhere, so I had only enough time to get home, put the new shims in, put the cams back in place, replace the cam holder, measure the new clearances, and discover that while one was perfect, the other was worse than before! The nice gentleman at BMW had mismeasured one of my shims and sold me one that made the clearance worse. So the following day I had to remove the cover, holder, and cams again and essentially do two valve jobs. I was seriously beginning to wonder if I should have spent the $500.

What is particularly stressful about this job—aside from the risk of shifting the timing and destroying your engine—is that you’ll drop a screw or shim down in the engine. My shop manual suggests stuffing a rag or paper towels in the engine to catch any of the eight cam holder screws that might do just that. The YouTube videos I’d seen had alluded to that possibility in a vague sort of way that caused me considerable concern, such as “that would not be good,” or “you really don’t want that to happen,” and while I’m still unsure of what that would mean, I imagine it would cost me a lot of either time or money. So I worked carefully and slowly, and as I started each of the eight screws, I felt like I was a child playing Operation again. It was right at the height of this stage of the procedure that my wife walked out to the shed where I was working to ask me one of those questions all husbands love, like what shall we have for dinner, or would I take this call because somebody’s doing a survey.

In one YouTube video I’d seen, someone shows how you can use zip ties to fasten the cam chain to the sprockets. This way you ensure your cams don’t shift relative to the chain, messing up your timing and damaging your valves. But when I tried this, I couldn’t get the cams back in; the chain was too tight and prevented me from putting them back in their holders. So I held my breath and cut the ties. (I held the ties too, lest they fall into the engine.) Fortunately, I’d noted, even photographed, exactly where the hashmarks on the sprockets must be at TDC. A couple of rotations of the engine ensured the timing was spot on and everything was opening and closing as it should and there was no gnashing of metal. Still, once I’d put everything back together, I was a little nervous the first time I started the bike. It made one cough and fired, then hummed, as quietly as a thumper can hum.

All this was admittedly a few months ago, before I did my New Hampshire trip. I wanted to do this work obviously before that tour. Then just the other night I saw this video by Ari Henning from MC Garage on how to do your valves. He admits that the job gives most people the heebie-jeebies and is a major pain in the butt because of the risks involved. I admit, if I’d seen this video before doing the job, my confidence might have faltered. In the end, I think I did alright! Now I don’t have to think about my valves for another 40,000 km. and can put that $500 toward a new saddle next year.

Next up, prepping the bike for winter storage.

 

Half the Fun

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Me under Car

I’m a teacher and so, as everyone likes to remind me, I get my summers off. I often respond by saying that it’s a good thing I do or I’d burn out. By the time the term winds to a close, I don’t want to be anywhere near a desk. I’ll shovel scrap metal before I do anything bookish, at least for a good chunk of the summer. Usually this urge to do something physical takes the form of athletic training or home reno, but this summer I dove into a large mechanical job on the car. I also did some work on the bike. Here are five take-aways I learned from this work.

  1. Be Methodical: When I do a job, I get nervous. Almost every job I do is a first for me, so I’m heading into uncharted territory. I’m worried I will make a huge mistake along the way that will ruin my precious bike or cost me more money to fix than it would have cost to get a professional to do the job. (This is supposed to be cost-saving, right?) Or I’ll encounter an insurmountable snag that will stop me halfway through a job. I’ll have to call in the professionals, and in the case of auto and bike mechanics, that will involve a towing charge as well as the cost of the job. So I often rush. It’s stupid, I know, as a reaction to the situation, and I’ve become increasingly aware of my emotional state as I work and have been trying to slow myself down. This job was so big I knew I had to go slow. Fortunately I saw this video by Ari Henning from MC Garage before starting. In it, he gives three tips for being a better motorcycle mechanic. Take photos. Use zip-lock bags to label and store parts, and use a manual. I’ll add to that to lay parts out in the order they came off. (My front porch smelled like a garage for a good portion of the summer.) This forced me to go slow and methodically. It’s easy to undo bolts and rip the engine apart; the tough part is putting it all back together again. So I used my phone and took a picture of every item before it came out. I used sandwich bags and a sharpie to store and label bolts. I also used masking tape to label cables that were detached. I kept a list of items in the order that they were removed. And I bought and used the Haynes manual, which shows step-by-step how to do the job.
  2. When Things Go Wrong, Don’t Panic: Mechanical work is all about problem-solving. Nothing ever goes as planned or as described in the manual, especially if you’re working on an older machine. Sometimes it’s just a matter of figuring out how you are going to get a wrench in there, but sometimes, as in my case, it’s breaking an important bolt in the most inaccessible part of the engine. When this happens, probably the best thing to do is to take a break. Step back and give a little think on your options. Maybe go online and see what others have done. But if you let your emotions get the better of you, problems can compound quickly.
  3. Mechanical Work is a Workout: People keep telling me these days I look fit. My wife says I’ve bulked up. Okay, I’m never going to be bulky, but I do feel in pretty good shape. There were days when at the end I was physically exhausted. Mechanical work requires strength—not the weight-lifting kind but core and endurance strength, especially if you are working on your back on the driveway using hand tools. You constantly have your arms raised, you have to do a stomach crunch to reach something, just getting in and out from under the car every time you need a tool is tough. Same goes for working on a bike, whether you are wrestling a tire off the rim, or compressing the fork-spring to remove a retaining ring. And since mechanical work is physical, make sure you keep your body happy. Be sure to eat and drink regularly, just like an athlete or you’ll find yourself grumpy, working slowly, making mistakes, and wondering why.
  4. Have a Back-Up Vehicle: 3/4 of the job involves getting tools and parts when needed. I bought everything I thought would be needed before I started, but inevitably s**t happens and you need something. My parts supplier sold me 2 litres of gear oil and I discovered I needed 2.7. I broke a bolt, so had to go buy a tap plus a new bolt. I needed a socket extension, crow-feet socket set, more Liquid Wrench penetrating oil, hardware, etc.. And while I’m on this subject, never trust the parts salespeople; they can give you a bum-steer. Be sure you know your liquids and volumes (from the manual) and, when possible, take the original part that you are replacing. Often these guys (and they are almost always guys) are looking at an exploding diagram of your engine, trying to locate the exact thing you need, or worse, using a text-based database. And it perhaps goes without saying to keep all receipts in case a mistake is made.
  5. Get Dirty: I spent some time at the beginning of the summer reading Mark Zimmerman’s The Essential Guide to Motorcycle Maintenance. It’s a good book (review to come), but to learn you have to get in there and get dirty. Start small and simple, like an oil change, or coolant change. Then challenge yourself and try a bigger job. I did the brakes (actually not that hard) and that gave me the confidence to try replacing the clutch. The other day I changed the oil in my front forks—again, not hard. Most of the time these jobs aren’t that difficult but you just need to have the confidence to try, which comes from doing simple things first. I learned a lot from working on my bicycle when I was young. I used to buy bikes at police auctions, strip them down, then paint, clean, and re-lube everything, right down to the ball bearings. The more I work on my motorcycle, the more I see just how similar to a bike it is from an engineering standpoint, although it was the practical work on the bicycle that first gave me familiarity with tools, problem-solving, and observation of how mechanical things work. Later this fall I’m going to attempt to adjust the valve clearances. I’ve got 40,000 K on the bike now so it’s time. I’ve never done this before, but I’ll figure it out, using my manual and taking my time.

Last fall I did the first service on my bike by changing the oil and coolant to prepare it for winter storage. I phoned my dad to talk about how it went. He told me about when he stripped down the engine on his bike and had it rebored. Pirsig says you should work on your own bike because a lot of mechanics are hacks, which is probably true. No one’s going to care as much about your bike as you, and doing it yourself ensures it’s done right. Pirsig also seems to suggest a moral reason for doing your own maintenance. If the bike is you, it’s your responsibility to take care of yourself and your bike. But my dad had another reason for doing this dirty work. Just before he hung up he said, “I’m glad you’re doing your own maintenance. That’s half the fun of having a bike.”

All About Oil

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motor-oil-101

My wife has a saying she uses to remind me to drink more water. “Water is like oil for your body,” she says. She knows which analogies work for a guy. I’m going to turn that around and say that oil is like the source of life for your engine. Using the best possible oil and changing it regularly is probably the single-most important thing you can do to maintain the life of your vehicle. Most of you probably already know this. Some people don’t. I once overheard a conversation at my garage with a woman who didn’t know she had to put oil in her car or where to put it. She’d let the car run dry and the engine had seized. But not to pick on women, I know a guy who did the same. “Ah, dude. Here’s your problem. There’s no oil in this car.”

Given the importance of oil, it’s surprising there are so many misconceptions about it. I fell to one recently by putting the wrong grade in my bike, based on a recommendation from the previous owner. He said, “You have to put 20W-50 in a single-cylinder motorcycle because it revs high.” So I did. Then I had trouble starting my bike once we got into the cold mornings of late fall and early spring. I started to suspect my cold-starting problems were related to oil, and a user forum referred me to bobistheoilguy.com. I don’t know Bob, but he knows a lot about oil. You will find at this site Motor Oil University containing ten classes complete with midterm and final exams. Clearly, oil is the source of life for Bob.

The following is, I hope, a fair summary of what I’ve learned mostly at that site, but also from user forums and conversations with club members as I researched the important decision of what to put in my bike. This should be useful for car owners as well as bikers.

Let’s start with some of those misconceptions:

  • Engine wear occurs when oil breaks down at high temperature
  • Oil grades like 10W-30 or 20W-50 refer to viscosity, or thickness
  • You should choose your oil grade based on the ambient temperature
  • Engines that run hot, like sports cars and hot-rods that have high revs, require thicker oil (this is the one I fell for)
  • You should change your oil when it turns black

Engine wear occurs when the engine gets too hot

Actually, 90% of engine wear occurs at start-up. And sadly, there is no oil on earth that fully protects an engine at start-up; a good quality oil can only minimize the damage. This is why it’s important never to rev your engine when you first start it, especially in the wintertime. My ex-wife used to get out of bed 10 minutes before her train left the station, then, in midwinter -20C Montreal, instead of walking the three blocks to the train station, would race there in our car immediately upon starting it. Don’t do this. No wonder she’s my ex.

To minimize the damage, you want your oil to be as thin as possible upon starting. So why not just buy the thinnest oil, you ask? Because there are actually two temperatures we have to be concerned about. One is starting temperature, and the other is operational temperature.

The two numbers on the oil container roughly correspond to these two contexts. But that’s about as direct a connection as you should draw, and many people (including Bob) suggest you forget about the numbers and labels for a few reasons. The W in 10W-30, for example—a reference to winter—is a misnomer. It would be more accurate to think of the first number in relation to starting temperature. Moreover, the numbers do not really reflect viscosity because viscosity changes with temperature. For example, according to Bob, a straight 30 oil has a thickness of 250 cS (centiStokes) at 75 F, but 10, the ideal viscosity, at 212 F, the optimal operational temparature.

The second number refers to operational temperature, but all liquid-cooled engines (i.e. most bikes and all cars) have a constant operational temperature of 212 F. Ambient temperature while running is only a consideration if your bike is air-cooled.

Confused? You’re not alone. Now let’s add another factor.

Mineral vs. Synthetic

There are few more controversial issues amongst bikers than which is better, mineral (i.e. traditional, dino) oil or synthetic. The debate in Hell between the fallen angels in Book II of Paradise Lost has nothing on the debates in user forums on this topic. If you want to have some fun, go to a popular forum (I won’t say which out of fear of being banned) and pretend to be a newbie, asking innocently which you should use. It’s like throwing a french fry to the lurking seagulls at a chip stand.

Many people believe the biggest difference between mineral and synthetic oils is that mineral is natural and synthetic is made in a lab. That’s a pretty big difference, for sure, but the more significant one for your engine is that synthetic is “naturally” thinner at start-up, the crucial time when most wear occurs. That is, it does not thicken as much upon cooling as mineral oil. The viscosity of the two are identical at operational temperature but synthetic has the edge on start-up. One point for synthetic.

Another difference is that, for example, a synthetic 10W-30 oil is based on a 30 grade oil and a mineral 10W-30 oil is based on a 10 grade oil. The mineral oil has additives in it that prevent it from thinning excessively as it heats up, and it’s these additives, not the oil itself, that break down over time. So with age, a mineral oil will lose its viscosity. This is why you have to change a mineral oil sooner, about twice as often, as synthetic oil. Second point scored to synthetic.

These additives age even outside of use in extreme temperatures. Don’t store your mineral oil in the shed during winter because it will lose some of its viscosity. In fact, contrary to what you might think based on what I’ve said above, Bob says that mineral oil ends up too thick, not too thin, with age. I don’t know why, and now I’m as thoroughly confused as you must be, but thankfully Bob offers this summary, twice, because it bears repeating:

“The synthetic 10W-30 grade oil is based on a heavier 30 grade oil while the mineral based 10W-30 oil is based on a thinner 10 grade oil. They are both similar at operating temperatures yet the 30 grade based synthetic is actually less thick at startup and much less honey–like at low temperatures. This is the opposite of what common sense dictates.”

It would seem that synthetic, in the red corner, is the winner, but wait: my BMW owner’s manual says “Alert: Do not use synthetic oil.”

Ah, there’s the rub

I’ve never seen any rationale for this, not at least from BMW, but there’s some anecdotal evidence on user forums that synthetic oil can produce clutch slippage. Remember your dad yelling at you, “Don’t ride the clutch!” when you were learning how to drive manual? That’s because cars have a dry clutch. But all bikes today have a wet clutch, meaning it’s lubricated by oil, the same oil that’s lubricating your engine, so you can ride it all you like, and should, because there are lots of times when you’re between gears.

Another difference is that synthetic oil is more slippery and lubricates better, regardless of viscosity. This can lead to the clutch slipping and, in time, burning out early, especially in older bikes with engines designed for mineral oil. The upshot is that gearing is much smoother, the engine quieter, and (so I presume) less wear.

High-Rev engines need thick oil

When I was 18 I worked as a self-serve gas attendant at Sunoco. We had cans of oil stacked on the shelves inside the kiosk and the tattoo boys would pick up 20W-50 for their muscle cars. Now at 53 (next week), I can laugh at them for wrecking their prized possessions. Bob says you don’t need that oil unless you are going to the track, not the bar or corner store (or gas station, for that matter). He says that for all he knows about oil, even in a hot engine, it’s better to go thin than thick. Why?

As I’ve said, normal operating temperature is 212F. At that temperature, most engines want the viscosity at 10cS. The thick multi-grades have a viscosity of 20cS at that temperature. Not perfect. But as Bob points out, when we increase the temperature from 212F to 302F, the 10W-30 thins from 10cS to 3, but the thicker oil thins from 20cS to 4, only 1cS difference. So the difference in viscosity in a hot engine is negligible while the difference at start-up is huge. If you need any more proof that a thicker oil isn’t worth the cost at start-up, Bob says that F1 cars run a straight 5 or 10 grade oil.

Change your oil when it’s black

No, change your oil when you’ve driven the recommended distance for the oil or when the recommended time has elapsed. (Remember, oil ages even when it sits, so even Grandma has to change it regularly. Maybe not her, specifically, but someone for her.) There are a number of factors that can turn an oil dark, but that doesn’t mean it’s lubricating less. Don’t believe me? See this page on motor oil myths by Valvoline. You’d think an oil company would want you to change it prematurely, but they say otherwise.

The final answer

What did I put in my bike? Because I’m a Gemini, I like compromise and put in a semi-synthetic 10W/40. (The manual recommends 10W/40.) This vid by Ari at MC Garage says not all synthetic oils are created equal and to look for one that’s Ester-based. I read that back in the 70’s, Mobil took Castrol to court for advertising its Syntec oil as synthetic. It’s all about the base that’s used. In the end, the court decided that Castrol changed its oil enough to call it synthetic, but if you’re looking to put a top-quality synthetic oil in your car or bike, look for one that has a base of PAO (Poly-alpha-olefin) or “esters” (chemical compounds consisting of a carbonyl adjacent to an ether linkage. Are you listening, my Chemistry colleagues?).

The other goof I made was forgetting to check the oil level at operational temperature. This is contrary to a car, which you check after it has been turned off for at least 30 seconds. When I took the bike out of storage this spring, I checked the level at start-up and, not surprisingly now, it was low, so I added a good litre. Doh! BMW’s have a dry sump system and it’s essential to check oil after at least twenty minutes of riding, with the bike level, pointed North, at a full moon . . .

Fortunately I caught that one before I caused serious damage to the engine. (Overfilling can cause seals to melt, among other problems.) Now I have the oil in it that I want, and at the correct level, which apparently is on the Min. line. I hear from both The Chain Gang and my BMW guy that these bikes don’t burn oil, and it’s better to err on the side of low than high. I think I’m set now for the season, including the fall. That’s good because an oil change on my bike is a full day affair. I’m envious of Pirsig who writes of changing the oil practically while Chris takes a whiz, while on my bike I have to remove half the fairing, the crash guard, engine guard, etc.. But what I pay in labour and cost for a good oil I gain in peace of mind, knowing I’ve got the best stuff possible for my bike in the crankcase.