Who gives a toss about valve-clearance checks?

[Hetzer]

The first service one mainly. I know specific bikes can gain a reputation for them being a particular issue, just as some others are 'bullet proof'. But, in general, even if a couple of shims do turn out to be ever so slightly off, is it worth the considerable expense or is it a bike-industry service scam?

I've never had one done, on new or old, and never had an issue as a result (high or low-revving engines).
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"There's the horizon! Ride hard, ride fast and cut down all who stand in your way!"

[kramdra]

The first check? Do it.

[Hetzer]

[gbrand42]

While its in warranty I would imagine it should be done as per the official schedule. After that I see no reason not to stretch the interval between checks. One of my old bikes should have been done every 16,000 miles which I stretched to 30,000 miles and even then the adjustment required was minimal, and I can't think it would have done any harm if I had just left it.
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Yamaha RD50M, Honda C90, Yamaha RS100, Yamaha RD125LC, Honda XL125 V9 Varadero, Honda NT700VA, Honda VFR800X, Honda CRF1000L, Honda ST1300 Pan European

[Hetzer]

The warranty is the only reason I can see for the need to have it done. Mine is due around 3000 miles, it won't be happening unless I happen to notice an issue with power (and even then I'd suspect something else; a shim would have to eat itself before it caused a meaningful issue).
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"There's the horizon! Ride hard, ride fast and cut down all who stand in your way!"

[spottedtango]

Some cars have hydraulic lifters that don't need adjusted.

I've only really adjusted rocker arm tappets. They don't hold the clearance that well and they can rattle loose.

Bucket and shim I don't bother usually especially on an I4. They don't go out that often and I can't be arsed spending an afternoon taking the cams out then setting the timing back up again. It's very easy to get a tooth out on some bikes.

Also bonus if it's a sports bike and you need to take everything off including the cooling system to get the cam cover off. Life's too short for that.

[MarJay]

If the clearance is too tight, the valve can ram into the valve seats which then screws with compression and you then don't get as much power, and you get odd running problems.

I wouldn't skip it on something like a BMW who do have something of a reputation for... err... suspect engine internals? Compared to Japanese manufacturers, they have tonnes of recalls for things like con rod bolts, engine finish and various other things. I wouldn't skip it myself.

Japanese bike? Maybe... but again if I want the full performance of the engine I'd probably at least have it checked.
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[doggone]

I tend to agree especially if you typically change your bike after 3-5 years and like me don't do many miles because there's more than one bike (plus limited riding time)
It's the sort of thing a dealer ought to do with any trade in but I bet they don't because they also know most jap bikes at least probably won't actually need it until getting on for 50k miles and would run well beyond that before any ill effects are apparent.

The only one (with shims) I ever had checked was an XJ900 on 25,000 and it didn't need anything doing.
Some older bikes use a locknut system mind and that's a different story but easy to do yourself I had a Honda CB250RS and XBR500 were done like that and did them annually after changing the oil.

[MarJay]

I had them done on my Street Triple at about 14,000 miles because of the age of the bike... One was tight. Not massively so, but enough to be worried.

I think I'm going to get my CBR and GSX done this year too. The CBR because it's done 20,000 miles and it's a track bike, and the GSX because it's only 3 years old but has done 25k.
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[Kawasaki Jimbo]

I know a very respectable independent bike shop who won't do valve checks unless there are reasons to think they are out. I'm not sure how they regard the first scheduled check though. I was pleased at first but having read a little bit on the matter I wonder if major damage is done by the time symptoms are felt. In fact I was thinking of doing the check myself because I have two weeks off (it would take me that long ). The bike did have a first valve check but that was at least 35k ago. Bucket and shim.

Aren't bikes usually out of warranty by the time the valve check is scheduled?

[Easy-X]

Worth checking? Certainly, IMHO. Okay, so you may have fairings and a tank to remove but it's not a fantastically hard job just boring. Now once you've checked whether it's worth the effort to swap out shims or get someone else to do the work is a separate conversation.

Not vital if the gaps are too big - just a slight loss of compression - but too tight = engine wear. For some bikes that could be the difference between a long life and immortality
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[Bhud]

I reckon you should do it. My theory: you have a brand new bike, which means when they assembled it they popped brand new valves into a brand new cylinder head. There could have been irregularities caused by casting imperfections between the valve lip and valve seat, which you've now hammered out by great force and heat cycling, when breaking in the engine. As you did so and the valves seated, the surfaces mated to form a better seal, and at the same time, as the rough bits of metal were worn away, the valves could have seated further in than how they were when they left the factory. Therefore it's important to check.

[Easy-X]

I think the point is that, beyond the initial service, the likelihood of massive deviation from spec of valve gaps and shims is almost so low to not worth worrying about. And the keyword is "almost"

Depends how you feel about conscientiousness. If you have to find all the secrets in Super Mario or Zelda checking valve gaps is right up there. If you have better things to do in life then more power to you... as long as those "better things" are tangible and not just procrastination
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[Bhud]

When people skip valve clearance checks and get away with it, one of two things have happened. Either they didn't put enough miles on that engine to notice, i.e. they sold it to someone (and that someone probably found it had bulbous valve stems if they ever took off the head), OR their engines fail and then mysteriously are never heard of ever again. Too embarrassed, perhaps. I'm not an engineer, yet my XJ600 never failed. And I kept the valves in spec, changing around 5 shims in total over 10-ish thousand miles.

[Robby]

Car don't need it because cars have had hydraulic lifters for decades. So have Harleys. Hydraulics lifters are self-adjusting. They work well in car engines and Harley engines, where the hydraulic tappet itself can be a fairly large part and move fairly slowly.

They work less well at high revs, and when you try to make them small enough to pack 16 or 20 of them on to a cylinder head.

Considering that few bikes do more than 40k miles over their lifetime, and a valve clearance check on anything with buckets and shims is done every 16k or so, it isn't a big enough problem to fix. 2 or 3 valve checks over the lifetime of the bike. More frequent on things with rocker arms, but also about a third of the workshop time to check and adjust them.

If the clearance is too tight, it means you don't have enough space between the camshaft, tappet assembly, and valve stem. The problems range from wiping the oil off the camshaft to holding a valve open all the time.

If the clearance is too big, it means you have too much space in there. Less of a problem for reliability, but it means the valve isn't opening fully so you don't get all of the fuel/air mix in that you could, or all of the exhaust out.

Whilst there are tendencies for shimmed bikes to close up over time and for rocker arm/locknut bikes to open up, this isn't a rule to live by. The valve clearance adjustments are accounting for wear in several places on several different materials.

Chances are, you'll be fine. It is unusual for valves to get so tight or loose that they cause a problem. It is one of those home-mechanic jobs where I feel that, overall, more damage gets caused by cocking up a valve check than would have been caused by just leaving it alone.

What bike?

[Hetzer]

[Hetzer]

I'll probably wait until 20k, then get them done when I replace the cam-chain (which is recommended at 25k miles because BMW engineering ain't all that).
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"There's the horizon! Ride hard, ride fast and cut down all who stand in your way!"

[jeffyjeff]

You can get a pretty good idea how long wearing your valve adjustment will stay in spec by looking at the manufacturer's recommended service interval. spottedtango hit it right. Shim under bucket designs tend to hold accuracy much longer and have service intervals in the neighborhood of 15-16,000 miles. Screw and locknut designs not so much. A YBR has a service interval of only 3750 miles. The good thing about that bike is that access is easy. I would not consider skipping valve checks on my oilhead BMW; it has screw adjusters, its air cooled, and relative to a modern sportbike, its temperamental. Why not invest a weekend and do it yourself? There is plenty of online help, and likely more than one YouTube video that can show you how to do it. The cost of any special tools and shims will pale in comparison to the cost of taking it to a shop. Back in the day, if you didn't turn a spanner on your bike, you didn't ride.
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History shows again and again how nature points out the folly of men - BOC

[Pete.]

[jeffyjeff]

[spottedtango]

[Pete.]

In fairness, you wouldn't expect someone to be asking if it's wise to neglect demos valve clearances.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[jeffyjeff]

[Robby]

[ThatDippyTwat]

On a new bike, I'd maintain the warranty, and just use your ear after that. You know how it's meant to sound. I'm having the Viffer checked. But that's mainly as I doubt it's ever been done more than once, it's on it's way to a quarter century old and it's got 117K miles and it makes all sorts of noises. Despite the valve geartrain itself being almost bomb proof, it is a fuckton of miles. While I don't mind doing rocker arms on an IL4 myself, shims on a V4 is not my idea of fun, so I'll be going against the grain and paying someone to do it, all I'll be doing is taking it up to them sans mid and lower fairings.
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'98 VFR800 (touring) - '12 VFR800 Crosrunner (Commuting) - '01 KDX220 (Big Green Antisocial Machine)