Skipping This Service COULD KILL Your Motorcycle! (Valves Explained)

[@kerrykalls7732]

I did a valve clearance adjustment with zero past experience and a Haynes manual leisurely over a couple weekends in the winter. Triple checked everything I did and kept all bolts in a cardboard cutout that mimicked the valve cover and cams etc. Turned out to be a perfect job and '06 636 still going strong other than needing another throttle body tune 4 years later

[@robertward1461]

Hell yeah... seriously considering learning enough to do this service myself too. Figure I'd pretty much be paying myself the $500+ it would cost me to have it done somewhere else, to learn myself. Long as I take my time and follow instructions I should be good. I like the cutout idea for the bolts.

[@brantleycombs3088]

How do you know if you need a throttle body tune?

[@gtbeech]

​@@brantleycombs3088 bit late but usually it's hunting at idle, rpm needle moves up and down, it can't find somewhere to settle as 1 cylinder or more want to sit slightly higher or lower.

[@Its_3055]

​@robertward1461 it's definitely good to know and can be a great starter point to learn the ins and outs of your bike. It seems intimidating to me but a bike is small and as long as you have good instructions and you keep everything organized, it should be relatively simple to do. It most likely will be time consuming though especially doing the service for the first time.

[@gregerymarshall5101]

Keep these tech talks tid bits coming. I'd be a great side discussion for the channel.

[@macc1370]

Just did valves on my xsr700. Took me the whole weekend but felt great to learn some new stuff

[@at9670]

Which tutorial did you follow? KZbin?

[@CaffeineFreak13]

Mechanic here, 1) spite isnt completely wrong about the valves being bigger and smaller than eachother for the straw reason, cus he broke it down barney style. but the larger factor in the intake valve being bigger is due to atmospheric pressure. 2) When he said shops charge by the hour, he is correct, but that doesnt mean shops get paid for the entire time they work on your vehicle. For the most part there are set labor hours for each job and each vehicle. The cost differences usually come from labor rates which are typically higher in big shops that have larger overhead costs and where they typically do everything by the book to extract every cent they can per job. For example your local dealership is likely to charge more for a job that a small shop would do for less cus their shop is small and it costs less to run

[@figol6272]

spite is missing parts regarding valve lash and 2 add head heat is a variable as well regarding power

[@figol6272]

porley ajusted valves can cause power lose and bad fuel consumtion

[@shyxguy6300]

wait wait wait. Valves get tighter clearances?? I thought they wear out which means the gap is bigger

[@diyeveryday67]

Most techs are paid on “flat rate”. Tech gets paid X hours by dealership regardless the tech requires more or less time than X. The labor time for a job is set by the manufacturer and does not vary. A good tech can earn 60-120 billed hours in a 40 hour work week.

[@icandsc]

I pose the same question I just commented to you : I've been reading up on this all winter, in preparation of doing my first scheduled valve job on my 83 cb1000 (my uncle was the previous owner, and didn't ride it much at all - its only just now at the 10k mark, and showing signs of needing adjustment). the main thing holding me back from doing the job at this point is the availability of the shims, because I don't know what sizes I will need until I start the job, and once I know, I will have to order any shim sizes that I don't already have. But I want to know - because checking valve lash and changing shims could potentially drag out the job because of shipping time, why not just order brand spankin' new valves and solve all the problems in one fell swoop?

[@ChrisG1392]

I think I've had a bent valve for about 8 years and 60k miles now. Marginally less power, makes a noise, but still runs (like a Honda).

[@ethansimpson4606]

lmao

[@ChrisG1392]

They say it's a belt tensioner pulley but I say bent valve. Who knows

[@lumine7653]

With a bent valve, you'll have no compression on that cylinder. It will run rough, vibrate more and the exhaust sound would be drastically different than before.

[@JayVee53]

Can you describe the noise? Would it be a slight rattling?

[@bve7397]

Just service it lol

[@Clawzz299]

As a newer rider, I like these tech segments. Learning about the inner workings of a motorcycle is quite dreading since there is so much going on and information is spread around everywhere.

[@santiagoardilesgonzalez6451]

I used to have a 200cc SOHC 4 valve 3 sparks single cilinder. It runs a sweet 10.000 rpm redline. Man I miss that bike. It was Bajaj Pulsar NS200 and had the BEST 200cc engine of them all.

[@cameronduplessis9479]

I'm studying mechanics at college and this actually helped me get up to speed, cheers guys✊🏍

[@nicholassilvestri1804]

Can I just say, the guys at Suzuki were saints when they put the screw/lock nut valve adjuster on the oil cooled GSXR's and Bandit engines. Takes literally 2 hours start to finish on my B1200

[@fredjunca]

The best engine 👍👍👍👍👍👍

[@craigg4246]

They did that years before the gsxr and bandit. That began with the 1980 GS750ET. I had one

[@wilremington6262]

As someone recently into motorcycling, started halfway through last season, this was absolutely perfect for me. I have a 2003 Yamaha FZ1 with 28k miles on it, so these were exactly the questions I've been asking.

[@0Rookie0]

26k+ miles on my '02 FZ1 and.. I think I feel "better" about pushing off the valve check after watching this video? Luckily it's a check and not an adjustment at 26k. These bikes are amazing, but I learned quickly that cold tires and second gear can be a bit hairy. No rider aids, ride it like a man haha. Make sure you set your suspension up. Even vaguely. It changed the bike for me. Also it has some of the best online and forum support known to man. Angelfire and cartestsoftware ftw!

[@zyonsdream]

Some bikes really require attention to the valves and some don’t. I had 48,000 miles on my CRF1000 Africa Twin and never touched the valves. Started easy every time, maintained consistent gas Milage, no abnormal noises or smoke. Ran the same from day one. Stock exhaust and filters and I didn’t ping it off the limiter. Bike was awesome until it got binned by a mini van.

[@richardcerritelli9657]

I thought the African twin was self adjusting valves I thought you didn't have to touch them.

[@zyonsdream]

@@richardcerritelli9657 I don’t know about the newer CRF1100 but the CRF1000 that I had used shim under bucket adjusters on the exhaust side and set screw on the intake if I recall correctly. I’d have to look at the shop manual to reconfirm that.

[@havikhobbies]

Valve clearance exists to ensure the valve closes fully so it can correctly seal against the valve seat. The valve is also cooled every time it seats, transmitting its heat into the cylinder head. If the valve train wears in way that the valve clearance is zero. The valve cannot fully seat in the head. Gasses can bypass causing a possible missfire and it and will overheat because it cannot transfer that heat to the head. A loose valve is a happy valve (until its way loose/loud) diminished clearance caused by lack of maintenance will eventually damage the valves, particularly burned exhaust valves are a common result.

[@MrEiniweini]

One of the selling points for the Sportster S was that you did not need to service the valves. I know bugger all about engines but I am happy now. I am likely to put over 15,000 miles a year on it.

[@Shortley]

How are you liking the sportster s? I had a chance to ride one and kind of turned it down, regretting that now of course. Lol

[@MrEiniweini]

@@Shortley It is surprisingly good. The clamshell seating position is not as bad as I thought it would be and the torque on it is insane. I daily commute with it and although going to work will never be your favourite thing to do ((unless you have a really nagging wife), I actually really enjoy the ride in. Rear brake is pretty weak but everything else is great.

[@richardcerritelli9657]

How does the bike ride I was always at the high-performance I have a Hayabusa I think about going over to like a cruiser sports bike combo I'm definitely not a Harley person what is the bike comfortable and does it have a lot of performance torque speed cuz they look nice the bike there more sporty now

[@MrEiniweini]

@@richardcerritelli9657 I like the ride position and power. It cruises at 4,000 RPM and that is the low end of your power band, so there is no grabbing down to get power or sitting at 8,000 RPM. The torque is on tap in the bikes sweet spot. I had to pay for a new seat though because the standard one has no back to it and you are on a 3.2 second bike (Corbin Gunslinger). I also got a 40mm up and 25mm back bar riser to reduce the clamshell ride position.I also got the HD windshield to take the air off my chest. It is worth a test ride but keep in mind that you will want to change the ergonomics if you want to enjoy it. The good thing is, it is a Harley and you can change it.

[@nbayard]

Sucking isn't harder than blowing. The straw analogy is a red herring because it's based on your anatomical limits. It's about pressure differential. Atmospheric pressure is way less than the pressure inside a post-combustion chamber.

[@thierryfaquet7405]

Actually no, the straw analogy is quite accurate. It’s all about compression and depression and your thoracique muscle can compress air and can obviously depress when sucking trough a straw.

[@sandspike2929]

I have a NC700 that I bought at 4000 miles. It probably had one valve check at 600 mile breakin checkup. I was under the mistaken notion that if the valves are not ticking, it is fine. And that the valve gaps get bigger with age, not smaller. So now I have 44000 on it and have missed 5 valve checks. A buddy of mine who has tons of MC knowledge convinced me that the valves needed adjusting and that I was risking my engine. And that I could do it myself. I do have the shop manual. So, after watching a video of it and reading the manual, I went to work. In the end I found out that my intake was 43% reduced and my exhaust 30%. After several hours of climbing the learning curve and calling my buddy for advice. It was done. First thing i noticed was smother idle. Today I took it out on the highway and what a new burst of power. Acceleration was Noticeably better. I will never forgo the valve check again. It is not really very hard on the NC700x. Anyone with tools and a modicum of mechanical ability can do it.

"It's super super reliable when it works".

[@TheAbhi945]

this video came in at a very right time coz i used to wonder why we need to get the valves serviced at some intervals and what is the significance of that,but now i know so thumbs up to the team

[@hvymax]

I did the MC mod on my KLR while I had it apart. It's also the perfect time for performance cams. I neglected mine for 30,000 miles till the valves weren't closing all the way when warm.

[@abyssflight3907]

the valve service interval for my TW200 is only 3,000 miles but on the other hand it's such an easy thing to do on the T-dub it only takes about 15-20 min.

[@sleeper.simulant7327]

I took my riding test on a TW200, I really want one now lol

[@GalamatiasOne]

I just adjusted the valves on my CRF250L last weekend. Both of the intakes were in spec, but both of the exhausts were out and had to be re-shimmed. At least on that model, it is definitely worth doing your own over the price you'd pay at the shop...yeah, it was a little bit of a pain in the ass, but anyone who is mechanically inclined should be able to do it in a couple hours or less. Anyway, I spent $80 for a shim variety pack and used 2 out of hundreds. If anyone is planning on doing a valve job on a Honda (7.48 mm shims), I'll sell you a shim kit for cheap!

[@mmuller199]

Spite is the only reason I still watch this channel. Great video, keep it up

[@zynetik]

VW VR6's cam chain and cam tensioner have the same issues as inline 4 bikes. You have to be wary of not having a bad tensioner or not skipping teeth. Most people end up selling their VR6's to avoid the same issue.

[@craigbomer8962]

I had a coworker with an 80's Yamaha 450(I think)cc parallel twin. He put a TON of miles on it and did all his own work (we're mechanics). He told me that the last time he checked his valve clearances, some of them had worn their valve seats so far into the cylinder head that there wasn't any room left for shims! He figures he has gotten his money's worth out of the bike and he'll replace it when it finally gives up.

[@getty6974]

It would be quite interesting if you actually made a video about Spite doing his klr or 690sm valve clearances.

[@ElectronNinja]

Doing your own valves is totally worth it if you have mechanical skills and want to try it (and save some cash too!). Agree with Spite, try your hand on something simple first, or, go do the more complex job with a friend who knows what to do.

[@ElectronNinja]

@@alastairtheduke Especially on a complicated machine it can be daunting, but if you have the factory service manual, engage your brain, and take your time, it's really no different than following some Lego assembly book. Still HIGHLY recommend doing it with someone who has mechanical experience though if you've never done it. Manuals don't talk about troubleshooting skills, how to deal with stuck bolts, etc.

[@scottarmbruster7759]

Good job Spite and well explained An excellent episode for those out there getting into bikes and aren’t mechanically aware

[@ijustfelldown]

I have a 50,000 kilometer Honda CB Unicorn (CB 150) and not even the official Honda service centre near me would check my valve timings. It's very rare to find mechanics who are good and confident enough to do valve service.

[@karlfonner7589]

Thanks for reminding me. My cam chain is a bit stretched. I have a hornet with 85,000 miles on it. It still runs but I treat it like a senior citizen

[@thinkingimpaired5663]

Mo Powah 4 ever. Kawasakis are easy to adjust and usually stay in adjustment for a long time because of the valve bucket over shim construction. The math is really simple as well.

[@tarnishedsquid2967]

I quite enjoyed this video. I really need to get my hands dirty more and maintain my motorcycle myself. I always just take it to a shop, when in reality most things can be done on you're own.

[@xEndgameRA]

Please make more of this kind of videos

[@AllanOhare-wx3wr]

Most important part of ridining and maintaining your bike!!!!!

[@ripntearslayer9101]

Lol this is almost funny. I'm getting an 82 suzuki gs850 running. For the valves, I gotta remove my gas tank then the valve cover. To get under my cams I just need a Cresent moon tool and I can scoop them out. I'm really starting to understand that a lot of the old ways were, in fact, better

[@ChrisGuthrie]

Fact - out of spec valves on a 07 yz450 can snap your leg in half with the Kickstarter.

[@JayD..]

Just did my this weekend, i mean it is intense to do by yourself 😅 but with a little help its actually manageable 😉

[@KrazyKanucker]

Hi Spite, maybe a quick rundown on finger followers for the next vid? For example, the one on Duke 390? I've read through some articles and watched some vids and still trying to get it clear in my head. Search "Camshaft finger followers explained south bay riders" for a good explanation. One key point from that explanation: "To gain low-end torque you want a shorter duration (shorter total valve-open time), however for top-end power you need a higher lift [maximum opening of the valve], which requires a very aggressive profile on the cam [i.e., a high rate of valve acceleration as it opens], which you can achieve using finger followers but not [with] a bucket-and-shim system."

[@BaitedyaPlaya]

Doing my valves myself for the last week, I bent a valve so I tore my r6 down, replaced the valve, have spent about 3 days now trying to get the timing right but I finally figured it out, checked the valves and I have about 5 that need adjusted which I’m doing now, I had a old head so I took a valve out of that one and this has been quite the job lemme tell you 😂 I’ve never done mechanic work until I started riding and fixing my own bike ab 7 months ago

[@trevonstewart3636]

This is where spite excels

[@riellydoyle6126]

Absolutely love these type of learning videos. I could literally watch these all day. Keep it up

[@kevinlugonzbi6005]

Love this video! Desmo is interesting because some did have non DOHC configuration. Also, weird one for you: Triumph Bonnevilles switched from DOHC back to SOHC in 2015-2016! Lost power, but gained torque and went water cooled. Really curious what motivated that decision. Would love more of this content too!

[@lasskinn474]

yamaha does sohc 4 valve on some small but not smallest single cyl engines. I think honda does too. you need a swing arm kind of a thing but it's not like you couldn't do it. it can save some space.

[@MansterBear]

@@lasskinn474 my VStar is SOHC 8 valve.

[@Motoboo_Marine]

Africa Twin motor is SOHC too iirc

[@natvega1]

I'd say the hardest part are the cam cap bolts, you can rare-ly tighten to spec with a bike that has many miles, the cam cap threads become weak, so if your cam cap bolts are 11ft-lbs by spec you might want to go with 9 or 8.😮

[@johnvirginia7238]

Thanks for the video I bought a 2015 ZX 6R with 16,000 miles on it 7 months ago and now I have 20,000 miles on it and I’m about to do this service myself. The engine is not making any sounds, but I like to follow the service schedule . I may even link up a tech on Facebook groups that I can pay to help me for the first time. I’ve already bought the service manual. I ride year round so it looks like I will be putting about 7k miles per year on this so I have to keep it maintained

[@horakilta]

Your seats wears the most and valves in the end stays a bit open which which can be heard as dropping revs slowly. If not completely shot they can be lapped and shimmed to spec again... ]

[@StormBringerVids]

I love the technical explanation. I would be curious to see more like this.

[@samus4799]

Notable exception to the DOHC setup, 300cc Hondas have a rocker arm. That way only a single cam lobe needed to move both intake or exhaust valves. Saves cost, rocker arms are much cheaper to manufacture than cams.

[@PremierNZ-qb5zd]

The only problem with this is that quite often the cam lobes can have a different profile between inlet and exhaust, this is so you can get a more efficient engine and generate more power.

[@John_Ridley]

If the wear is on the valve seat, then the valves can sit higher and higher, reducing the lash. If the lash gets to zero, then you start getting the valves not sealing completely, and you can burn valves.

[@MrAlexshellard]

100% more of these please my dude!

[@_davidsuciu]

Thank God i only bought a 2 cylinder bike.. 16 valves seems like a huge pain to adjust, but 8 doesnt sound that impossible..

[@233kosta]

Naw dude, exhaust gas is under a lot of pressure, even at BDC. That valve can be smaller to allow for a bigger inlet valve. Believe it or not, most of the cylinder empties itself. The exhaust stroke gets that last bit out and readies the piston for inlet. Good exhaust scavanving helps 😉

[@Joslin2311]

I really enjoyed this one. I hope to see more content like this. I'm a mechanical noob so it was super helpful to see it broken down

[@hotchihuahua1546]

One of the most overlooked services . There is a partial reason why this service is not being done and it’s a gamble . It’s labor intensive and costly if you can’t do it yourself . If you wait to long a valve adjustment won’t correct the damage done to the rockers , cams , valves and seats .

[@reggylippens6259]

very good tutorial perfect explained ......if you buy sportbike learn to work on it by the original bike manual cost more but thats most accurate ....in belgium valve job can cost you between 350 eu to 500eu ....thats 380 to 550 usd btw....550 usd is worth to learn work on your bike but valve job most be done perfect like spite say you can total ruin the engine

[@dougiequick1]

ANOTHER point is that it IS totally possible to engineer bucket/shim valve system that does NOT require removal of cams! How you ask? It must be engineered to allow use of valve spring compression tool wherein you simply pop one shim out with a magnet and slip in the proper spec shim ....the original Z1 900 you COULD do this with and WHY that has not been continued? idk but THAT was cool! and I still have the tool of that from my couple years as a Kawi mechanic ...dealers LOVE expensive service so maybe it is a way of rewarding dealers Idk but the status quo SUCKS! Motorcycles in my opinion ought to be designed to for ease of maintainece! There is NO excuse for example for an air cleaner to take more than 5 minutes to check and/or swap but many it is quite the ordeal .....same with spark plugs or getting to vaccum ports to balance cylinders etc...I LOVE very powerful motorcycles but I think they CAN be made much easier to WORK ON damn it!

[@craigg4246]

The original GS Suzukis had this same system. So did some Hondas. It is called shim on top. This is a very good, quick and easy type of valve system to adjust and maintain. The only problem with it is, the shim is much larger and heavier than a shim under bucket design. This extra mass limits peak rpm. Because if you rev it high enough to get valve float, the engine will spit the shim right outta the engine. I saw this very thing happen to Freddie Spencer at a laguna Seca Superbike race. It destroyed his engine, and made so much smoke you couldn’t see the track. But I would love to see this design return for the lower, say 10,000 rpm and under engine designs. Now my Suzuki 1050 Vstrom is an ingenious valve design. Yes, it has shim under the buckets, so the cams have to come out, and there are 4 cams, not 2 on a V engine. But the cams just pop out, without disturbing the cam chain or timing. They pop back in just as easy. This is a great solution to the trouble with adjusting shim under bucket designs.

[@moosecat]

Spite IS right...you don't have to check your valve lash. Nor do you have to check your tire pressure...or how much fuel you may (or may not) have in the tank. Of course, the stakes for not checking can become pretty expensive--if not dangerous. (Having a motor suddenly lock up at 60 mph, which then locks the transmission and rear wheel, is NOT enjoyable...AT ALL!!!)

[@0Rookie0]

Correct, however the failure usually comes well after the problem starts and even shows itself. You'd never notice a tank of gas being low. I'd say the most dangerous thing is living with a bike that seems fine but over time has developed a tick that you don't notice anymore. That's what I'd fear. Like a transmission that's "always clunked" when it really hasn't. Pushing off a check can be fine as long as you revisit it with scrutiny every now and again. Or know a trustworthy mechanic who would know the difference between valves doing their thing and being extra noisy.

[@kauklend2848]

I own a VFR800 Vtec, I am not gonna do my valves... Very informative video though, keep it going as always!

[@VegasDave3000]

I was surprised you didn’t briefly touch on the next evolution from DOHC, FreeValve! 30 seconds more, and a really cool idea if it makes it to motorbikes!

[@bve7397]

Luckily my old honda 650 has simple sohc, adjustable with screws simple as it gets tbh. Great to learn on, just did them this weekend second time but this time on a vtwin. The hardest part was getting to the engine 😁

[@silverbullet836]

We need more technical videos like this!!

[@dillanristow8750]

Pls do more of these type vids and plsss make a video of spite trying to figure out how to do valves

[@johnmonsalve11]

Great great video. Will that shop let to do a video(s) of that service being done?

[@Adhanks91]

Good lord this is an important topic, that being said, valves are something Ive never worked on. Don't really trust a shop to do most work, but damn I really hate taking the engine apart

[@cmoney0129]

Special thanks from the jackass who bought a 1999 zx6r that doesn't quite run right, before taking the msf course. This reinforces my theory that the valves need adjustment. And don't worry, I will be taking the course as I'm fixing it up.

[@mgkleym]

There is a big exception to the use of overhead cams. The ls moter family over at gm uses push rods.

[@itsshey1644]

I love this because even though i dont have a bike im learning so much

[@brennanrogers7947]

Should do brake system rebuilds next titled "Skipping this bike maintenance can kill you"

[@andrewmelalueca4881]

Hot exhaust gasses are far less viscous, therefore easier to push out of the combustion chamber.

[@sbsb4995]

Can I avoid doing the valve service if I do not rev to the moon?

[@Mrdietryon]

Love this video and I could totally listen to an hour long version of this!!

[@GNelson1989]

I just got done building my Harley and you’re right the push rods are easy as hell

[@someguy9520]

My 98' deauville still has SOHC. The successor (2006-2012) also has SOHC with 3 valves/pot In forums they did valve checks like suggested by the manual, but they discovered that it went out of whack only by 1/10 of the maximum allowed clearance after 50.000km So most users dont do em(just in this case with this engine)

[@brucearena]

Great detail on explaining difference in intake/exhaust valve sizes

[@East_TX_LCR]

More videos like this please Spite.

[@jonathan84166]

I just got into bikes and your videos are so enlightening !!

[@chisomdavid5692]

that's the side I love most fixing my bike

[@xpllmmff]

If valve adjusting is such a hassle to bear with, I don't know how Royal Enfield owners could get along with 5000 kms adjusting intervals, meaning they have to do all these stuffs every 3 - 6 months.

[@benning7bass]

I think you should make an in depth video on the valve service of this ZX6 before you give it away.

[@ashleycalhoun1824]

This wouldn't be a huge deal if manufacturers didn't put a mount of obstacles between you and the valves...

[@peterhallbus1114]

would not mind an hour long detailed video about valves ;)

[@jeffrielley920]

Pushrod engines are smaller, lighter, create more torque at low rpm's, are less expensive, more reliable since they have fewer moving parts, and can have a lower center of gravity. Harley uses pushrod engines for the same reason Chevy put them in the Corvette for so long, not because there are a bunch of WWII vets in Milwaukee designing engines who are just derping along.

[@Idlehandzx2]

I love these types of videos

[@ommanomnom]

damn, i literally just paid £500 to have all my valves, tappits, and gaskets replaced. Should have watched this

[@walker2837]

Good stuff. More of this type of content please.

[@ribalderr6052]

yep, this is a must maintenance u cant pass up. NO guys u cant plug in USB tap a few keys an do this. what I see looking at young guys bikes is little to no maintenance. even chain. even a wipe down, a wash. lubrication. and theyre on old old bikes an ripping it max too. bikes arent like the lil japanese cars nowadays. or any cars. theyll catch on later I hope before its too late an they dont have a catastrophic incident before they get it. kudos to u for going over this, a simple this is a 4 stroke engine heres how it works, heres the valves. intake. exhaust.. use to be shop classes in school, and we took apart everything to see how it worked when I was young but that was another world ago.

[@micko1404]

Valve clearances aren't that hard. As long as you do the math correct, usually you can mix and match shims to minimise the amount of new shims required. Lots of fun doing valve clearances on an old Yamaha Genesis engine where you have 5 valves per cylinder.

[@CaptainFeathersword]

Awesome vid, Spite!...more like this please!!!

[@maverickyoung9602]

PTSD from donut media “suck squeeze bang blow. Gas it up and off you go”

[@stuartgreig6609]

Good video, as I don't have a modern 16v engine it's not really relevant to me. Mine is DOHC 16v but nice and early so still has rockers and screw and locknut adjustment so easy and simple to do. Also I'd disagree with some of your generalisations, my CX had pushrods but 4 valve heads, my Rotax single had a SOHC with 4 valves. I do wonder sometimes if the move to bucket and shims was more to do with manufacturing costs? At least we don't have snappy snappy belts like cars. 🙂

[@epicfacecanada]

As I understand it the reason for the switch to shim-style valves over the old screw-style valves is because of 1. Smaller Packaging (particularly for DOHC) 2. Less weight. Allowing the valves to work better at high RPM

[@irzekk]

Love love this content

[@Chase_N]

Everyone- Why do so many sportbike guys switch to Harleys? Anyone that's had to pay for a valve adjustment- Now you know why.

[@lethargicstove2024]

Probably easy to do on a Honda goldwing aswell

[@sleeper.simulant7327]

That and riding a crotch rocket on the street gets real old, real fast…

[@hvymax]

I miss the screw and nut valve adjustment. Easily done in minutes. My KLR was down for a week waiting for shims

[@wubstepgrandma]

You have a dohc... You just do. Me looking very confused at all three of the bikes in my garage being Honda sohc4 classics...

[@sambeezy007]

I have a 2020 Ninja 400 and almost at 15k miles and about to get this $1,100 service done involving valves.

[@johnantonopoulous6381]

They can get longer/ the shims get fatter and make the tolerance tighter which means the valve or shims are longer/ fatter and there duration and lift get longer

[@1panic0]

Well, I'm screwed. My Benelli is a little over due for valve checks. At this moment my timing chain sounds like a pocket full of coins. And my engine doesn't sound too healthy. It's got 26,6800km

[@tylerblais9296]

Love the content… Spite, so your thang “not so noob”

[@dddon513]

They're not that hard to work on, especially with inline Japanese bikes. I'm actually surprised when one of those even needs it.

[@tyguymoore]

You say that my bike probably has DOHC, but I have an electric motorcycle. I’m pretty sure my Zero does not have a DOHC

[@wedgeserif556]

So, I'm gonna be the physics nerd and explain a little more accurately how "suction" works. Suction isn't actually a force. The force that moves air comes from the atmosphere itself, the weight of a planet's worth of gas bearing down. We measure this pressure as 17 pounds per square inch (psi). When the piston is at the top of the cylinder, there's still a chamber above it with some air. When the piston moves down, the chamber expands, reducing the pressure within it. When the intake valve opens, the pressure differential allows that 17 psi outside the engine to push air into the cylinder. It's the same mechanism as drinking through a straw: your tongue moves down within your mouth, creating a pressure differential that allows the atmosphere to push the drink up through the straw. You cannot drink through a straw in a vacuum. That's why the intake valve is larger than the exhaust. The atmosphere pushes the air from all directions outside the engine, distributing the force all around. A larger aperture is needed to allow that distributed force to do its thing. When the piston moves up, the force on the air comes from one direction, rather than all of them, so a larger aperture isn't needed.

[@0Rookie0]

TLDR of the in depth explanation: "Suction" or "vacuum" can only be so strong in an atmosphere. "Exhaust" or "pressure" can be as high as needed. The limits of the two are different. Bigger valves help the atmosphere do it's pushing.

[@ariachemodanova9251]

Awesome vid. Very informative!

[@neilius1015]

Great video and I hope you do more of these but…it’s not hard to see how electric bikes will interest a lot of folks once they become affordable…