The complexity of modern valve trains and maintenance costs

[Mailman]

Taken from this article,
https://www.revzilla.com/common-tread/complexity-in-our-motorcycles

The article talks about how modern engines have become marvels of power and reliability, but at the cost of complexity of design. The writer uses the Indian Scout as his example, stating that on its surface it is one of the more basic motorcycles, but the engine design is complex.

“ a valve check that appears to be worth about six hours of shop time, with a street price north of $1,000 at the time of this writing. And that's assuming the valves are within spec. Any adjustment will cost quite a bit more. Gone are the days of the screw-and-locknut adjusters where checks and adjustments happened at the same time for basically the same amount of labor. No, these Scouts, like many modern motorcycles, require measurements to be taken, like all bikes. But if adjustment is needed, cam removal and special-order shims are the order of the day,”

When I was looking for a new bike, there were several bikes that I really liked, such as the Triumph twins, the Honda CB 1100 and others that had a retro design that I found appealing but I knew I did not want the hassle of valve adjustments that required removing the cams from the engine to achieve. ( That still blows my mind! ) I cannot even imagine what BMW charges to check and adjust the valves on one of their six cylinder bikes with 24 valves! And a Ducati dealer charges $1500-2000 to adjust their proprietary Desmo valve train.

There are other modern retros , most notably the Kawasaki W800 such as @Raymond has, that has an absolutely genius valve train, in which the rockers are spring loaded on their mounting shaft and you simply slide the rockers over with your finger to access the shims! Brilliant!

A few , not many, new bikes have hydraulic valve lifters, which removes that maintenance expense, but adds extra parts to the valve train and in most instances limits higher RPM’s. Harley Davidsons new motor uses a combination of hydraulic lifters and computer controlled variable valve timing ( and liquid cooling ) to achieve high horsepower.

When I was shopping for a new bike , one of my criteria was that it had screw and tappet adjusters that I could do myself, so as to avoid costly shop service bills. I got that in my current bike but, man I didn’t count on the lack of room to get in there to do the job. I can barely get my fingertips back to some of those valves.

I wonder how many guys , that are not very mechanically inclined , buy a new bike without ever thinking about how much it’s gonna cost them to have routine maintenance done at a dealer?

 

[Raymond]

A good topic, Bob!

The W800 as you correctly say needs very basic maintenance, easy enough to do at home - the only thing I'm not sure of is the Throttle Position Sensor which is supposed to be checked using a special harness and a very accurate volt meter or sommat like that - but it's worth pointing out while the W800 is a marvel of reliability it is also not super powerful, I think Big K claim 47hp, when 600cc sportsbikes are putting out claimed 120hp plus.

The cost of maintenance might be something that new owners don't think about or something they think about and take into consideration? I've heard many times that Ducatis for example are put up for sale before they reach the BIG service milestone at 15,000 when the cam belts have to be changed.

Far cry from the days when young blokes with not much money rode mainly British bikes, or maybe Harleys in the US, spent Saturdays doing the maintenance and Sundays out riding with their girl on the back. Back then bikes were basic transport for the young and impecunious but now they are an expensive 'leisure product' for an older generation with a lot more disposable income.

So the mainstream motorcycle market business model requires some comfortably off bloke, or woman of course, with enough money to splash on a toy/fashion accessory/thrill machine which will probably do a very low annual mileage and be taken back to the shop where it was bought for all maintenance. Stacey at Surrey H-D told me about one customer, woman maybe in her thirties, 1200 Sportster Dark, brought the bike in each year for its annual service and each year the mileage was little more than the 20 miles or so from her place to the shop. Wot a waste.

And the manufacturers are building very sophisticated bikes with complex valve trains, high power engines, advanced metallurgy and whatever else is needed for track success to build sales on, which are then going to be sold to people who . . . well alright, they're not dilettantes but they're not the kind of bugs in the teeth bikers . . . well let me put it another way. Our predilection for old bikes with rough edges and doing the work ourselves puts us on a different planet. Or even a lost world . . .

 

[Mailman]

I've heard many times that Ducatis for example are put up for sale before they reach the BIG service milestone at 15,000 when the cam belt has to be changed.

I see that all the time here on our local Craigslist.

it's worth pointing out while the W800 is a marvel of reliability it is also not super powerful

The same can be said for my Suzuki 800, my old Suzuki 650 V-Strom could’ve been a half mile down the road before I could even get the kick stand up on my cruiser!

 

[Grimly]

I've heard many times that Ducatis for example are put up for sale before they reach the BIG service milestone at 15,000 when the cam belt has to be changed.

... and yet, if you have the right models, the cambelt is available from Gates for a handful of dollars. I'm not saying all Dukes are as easily / cheaply re-belted, but a lot of them are.

Back then bikes were basic transport for the young and impecunious but now they are an expensive 'leisure product' for an older generation with a lot more disposable income.

Huh, tell me about it. For the past several years I've been batting down attempts by dealers to charge me Motorcycle Leisure Tax.
Jeez, you'd think their stock was gold-plated, the stupid money they want for some things.
Too many clowns with too much money and too willing to pay the asking price - and that, allied with greedy sods on the other side of the counter, only too willing to take it.

 

[gggGary]

Got an old CB900F to do, they were still shim over bucket so not too bad.
Done the Beemer R1200GS, it's screw and nut, WAY out in the open.
Allison's Honda wizomatic is hydraulic. A lot of the Honda 270 parallel twins are hydraulic.
The Ulysses is hydraulic. Doing spark plugs on that is a big deal.
Several of the big sport tourers I've had were bucket over shim, MeaCulpa I never checked the valves on any of them. The Kaw Concours 14 forums report many when checked at 60-90K miles still have valves in tolerance, and that's fairly common on many of the bucket over shim designs.
Some of the sport tourer guys pull the tupperware before the trip to the dealer cuz a lot of the labor is doing all the fairings.

 

[Mailman]

Several of the big sport tourers I've had were bucket over shim, MeaCulpa I never checked the valves on any of them. The Kaw Concours 14 forums report many when checked at 60-90K miles still have valves in tolerance, and that's fairly common on many of the bucket over shim designs.

Yeah from what I’ve read, they don’t typically require much in the way of adjustment. The first bike I had with them was my 2007 Triumph Bonneville. It was the first modern and new bike I’d owned since the 70’s so I thought I’d take it to the dealer for its first major service that called for a valve adjustment inspection. Yeah…..I bout swallowed my teeth when they hit me up for $550 and that was just to check the valves, no adjustment was necessary.
I won’t make that mistake again.

 

[gggGary]

Toyota used lifters in various sizes (no shims) to set clearance at the factory for a while. Basic theory; once n done, low cost, fewer parts. They went back to hydraulic lifters prolly cuz of owner neglect/abuse causing wear, making even dealer valve setting tedious and lengthy.

from a Prius forum;
"I see this is an old post, but there should be a response in this thread. It's in the Gen 2 forum, so the engine is the 1NZ, and the reason there are more people replacing 1NZs than doing valve adjustments is (1) replacement engines can be had pretty cheaply, and (2) valve adjustment on the 1NZ is crazy impractical.
1NZ valves are adjusted at the factory by choosing each intake valve lifter to be one of the 35 available sizes for those, and each exhaust valve lifter to from among the different 35 sizes for those. At the factory, this is easy, because all 70 lifter choices are right there to be chosen on the production line.
To field-adjust a 1NZ, you have to (1) measure all the valve clearances to determine how far each clearance is off; (2) remove the camshafts and all of the lifters, keeping them in order; (3) measure each removed lifter to determine what size it is; (4) do the math with the clearance you measured to determine what size you need; (5) order the sizes you need; (6) wait around with your car apart until they all arrive, including the one that wasn't in the warehouse and comes on the boat from Japan; (7) reassemble the engine.
If you're in a hurry, you could order 560 lifters before you start, and try to return 544 for a refund after you're done. Not that I've heard of anyone successfully using that approach.
Sometimes people talk about "shims" when describing that sort of adjustment. There are no "shims" in the 1NZ. The entire lifter is what comes in 35 sizes, and the entire lifter is replaced. To have a full selection of those in stock would be a mid-four-figure investment.

Hence, a lot of people replace 1NZ engines when they wear out."

 

[RC4MAN]

"Back in the day", well yeah I remember doing screw tappet adjustment to my Brit bikes and my Dad's Hondas every 2k-3k miles, along with points, condensers, carb sync, cam chain, primary drive chain, etc. ad-infinitum
My V-Rod HD charges $500 minimum to do the valves. Though in reality I had it done by the dealer at 25k miles and never since, at 80k miles it still runs liek a top but I don't abuse or hot rod it. That's been the benefit of materials, tolerances and shim type valve adjustment, all adds up to extended service intervals in real life.
Kawasaki uses that sliding rocker in other engines as well, the 900 V-Twin comes immediately to mind, easiest valve adjustment I ever did on an engine.

 

[bosco659]

Then there’s the Moto Guzzi. You can adjust the valves while sitting in your favourite recliner. lol.

 

[Mailman]

Then there’s the Moto Guzzi. You can adjust the valves while sitting in your favourite recliner. lol.

I actually ordered a brand new Moto Guzzi about a year and a half ago for that very reason! Well …that and the fact that I’ve always been in love with them.

But, they were having supply chain issues at the time, that and the fact that they were trying to get a new factory up and running in Italy. When they told me it might be 8-10 months before it arrives, I got my deposit back.

 

[jetmechmarty]

Then there’s the Moto Guzzi. You can adjust the valves while sitting in your favourite recliner. lol.

View attachment 257442

There’s a big plus in the Goose column.

 

[cra-z1]

I can't wait to check the valves on this baby. First thing you need to do is remove the radiator to get at the valve

cover after removing all the plastic. Bottom line is if you are not mechanically inclined your going to have to go to the dealer.

 

[jetmechmarty]

If I need a dealer to service my motorcycle, I had best not buy it. At least, not where I live. It appears H-D are the only competent dealers. XS Yamahas don’t need the dealer. Double plus in their column.

 

[bosco659]

I can't wait to check the valves on this baby. First thing you need to do is remove the radiator to get at the valve View attachment 257445cover after removing all the plastic. Bottom line is if you are not mechanically inclined your going to have to go to the dealer.

I find with newer bikes, the first time you take them apart, quite often you break tabs and clips because you’re not exactly sure how to take the plastic bits apart. I’ve also found they are a good source of hardware because usually after I’ve finished with the reassembly, I have spare parts left over.

 

[arcticXS]

Definitely food for thought. And on a brand new bike with warranty, following the prescribed service intervals at a dealer is a requirement for having a valid warranty anyway. Not much one can do about that, except check service costs before buying. (Which I DID NOT do before buying the. NC750X .....)

Enough of that, now stop this Ducati bashing! I have worked a lot on 2 valve/ air cooled Ducatis from 1990 onwards, and also a bit on my water cooled/ fuel injected 2 valve ST2 944. In fact, I would prefer working on these bikes over any inline four dohc bike. The opening rocker on these 2 valve Ducatis also slide sideways, for dead easy access to the opening shims. You just need to pull a spring clip off the rocker shaft, then carefully rotate the engine to find the spot where it slides out (due to the Desmo system). Closing shims are a bit more fiddly, but no biggie either. As for shim selection, I just keep notes of what shims are in the different locations, so if a clearance is out of spec, I can order that shim before tearing anything apart. Another nice feature, is that 2 valve Ducatis have no head gasket, just o-rings for oil galleries, and for Paso and ST2, coolant. So if you want to take the heads off, and do the valve clearance adjustment on the dining table, that is a small job.
Finally, cam belt replacement. Which is a ridiculously easy job. On my 1995 600, it requires a 5 mm Allen key or socket for the belt covers, and the same 5 mm Allen for the belt tensioner adjustment. To replace the static roller, you may need an open ended 10 mm IIRC.

That's it. Sorry, but if you were to compare time spent replacing Ducati cam belts and tensioning rollers vs replacing XS650 timing chains, chain guides and adjusting chain tension, over say 100 000 km, the Ducati would come out with less time spent.

V-engines in general are more awkward than inline engines when it comes to intake and exhaust plumbing. But beyond that, a 2 valve Ducati is actually pretty simple, easy to work on, and almost infinitely rebuildable, due to ball bearing cams and cranks (big ends are plain bearing)

 

[Mailman]

Enough of that, now stop this Ducati bashing! I have worked a lot on 2 valve/ air cooled Ducatis from 1990 onwards, and also a bit on my water cooled/ fuel injected 2 valve ST2 944. In fact, I would prefer working on these bikes over any inline four dohc bike.

Thanks for posting that! It’s interesting to hear about the routine maintenance from a Ducati owner with mechanical ability!

 

[Paleomechanic]

Definitely food for thought. And on a brand new bike with warranty, following the prescribed service intervals at a dealer is a requirement for having a valid warranty anyway. Not much one can do about that, except check service costs before buying. (Which I DID NOT do before buying the. NC750X .....)

Enough of that, now stop this Ducati bashing! I have worked a lot on 2 valve/ air cooled Ducatis from 1990 onwards, and also a bit on my water cooled/ fuel injected 2 valve ST2 944. In fact, I would prefer working on these bikes over any inline four dohc bike. The opening rocker on these 2 valve Ducatis also slide sideways, for dead easy access to the opening shims. You just need to pull a spring clip off the rocker shaft, then carefully rotate the engine to find the spot where it slides out (due to the Desmo system). Closing shims are a bit more fiddly, but no biggie either. As for shim selection, I just keep notes of what shims are in the different locations, so if a clearance is out of spec, I can order that shim before tearing anything apart. Another nice feature, is that 2 valve Ducatis have no head gasket, just o-rings for oil galleries, and for Paso and ST2, coolant. So if you want to take the heads off, and do the valve clearance adjustment on the dining table, that is a small job.
Finally, cam belt replacement. Which is a ridiculously easy job. On my 1995 600, it requires a 5 mm Allen key or socket for the belt covers, and the same 5 mm Allen for the belt tensioner adjustment. To replace the static roller, you may need an open ended 10 mm IIRC.

That's it. Sorry, but if you were to compare time spent replacing Ducati cam belts and tensioning rollers vs replacing XS650 timing chains, chain guides and adjusting chain tension, over say 100 000 km, the Ducati would come out with less time spent.

V-engines in general are more awkward than inline engines when it comes to intake and exhaust plumbing. But beyond that, a 2 valve Ducati is actually pretty simple, easy to work on, and almost infinitely rebuildable, due to ball bearing cams and cranks (big ends are plain bearing)

Ditto!
I owned and maintained two ducs along way from anywhere when I lived 50 miles north of Whitehorse, Yukon

Used Gates belts from a heavy equipment dealer in town, never an issue maintaining those two.

I also ran an XS, which was great too, and we had two bike shops in the city , Yamaha and Yukon Harley Davidson ( which closed back in ‘11)

My smaller 620 had decent multi use rubber , the most “posing fun” I had with that one was my run up the Dempster Hwy , by the Arctic Circle sign ….being Practically crowded out by a squadron of BMW “adventure bikes” with more weight than the bikes themselves….and me with a backpack and soft bags ….

Oh, for the brave salvage types here…behind the only stop up the road , at Eagle Plains …there is behind the gas station, a pile of absolutely crashed BMW 1200’s …

Light, simple to operate and maintain rules the roost up there

I’d have zero issues running my 76 XS up to Inuvik

 

[Melnic]

I'll be happy when I put that many miles on my Scout and Bonneville and pay the shop to do it and bite my lip while paying the bill.
I plan to just do the oil changes, fluid checks and belt/chain adjustments. Plus brakes of course, I'll do that. Anything like valve adjustments I'll be paying for it when the time comes if I have not changed bikes by then. My current 2 vintage bikes is where I'll wrench turn .

I see it no different than many new cars. The way they engineer the cars for specs and cafe standards, service is a pain.

 

[40north]

Late night thought, looking at the engines of the 1930's, the exotics were very complex...I can imagine better though, with digital logic servo control of valve opening and timing, and so forth. There is no particularl need for camshaft anymore.

Seems to me that what's happened is that it got cheaper to build sexy machinery due to better machine tool technology. and reduced labor costs.

I was looking at the primitive commie tank motor https://en.wikipedia.org/wiki/Kharkiv_model_V-2 Dual OHC V 12 diesel 4 valve... I'd be proud to have one in mah ford ...

 

[Paleomechanic]

... and yet, if you have the right models, the cambelt is available from Gates for a handful of dollars. I'm not saying all Dukes are as easily / cheaply re-belted, but a lot of them are.

Huh, tell me about it. For the past several years I've been batting down attempts by dealers to charge me Motorcycle Leisure Tax.
Jeez, you'd think their stock was gold-plated, the stupid money they want for some things.
Too many clowns with too much money and too willing to pay the asking price - and that, allied with greedy sods on the other side of the counter, only too willing to take it.

Yep.
I changed my Ducati Monster belts myself with Gates replacements.
I had an older aircooled one, it wasn’t too bad of a job really ( but the first time I’ll admit, the scare factor was pretty high!)