Valve Clearance - how, why, when?

[@chetanpatel1464]

Nice, I finally have an explanation of why I have to do valve clearance checks on my motorcycles. And it's good to visualise why this clearance changes over time.

[@nomdeploom5707]

Absolutely spot on mate. Almost all my questions were answered. But why is intake/exhaust different - Check OK, so where should you aim for? - Check But what's causing the wear then? - Check 2 Questions remaining though - Why do some people say they prefer to aim tighter on some bikes & why the hell are the shims not in smaller increments. That last one was just me venting tbh.

[@dirtygarageguy]

1) because people are dickheads 2) because they'd have to bloody loads and then keep them in stock. For every bike made that would be millions of shims

[@nomdeploom5707]

@@dirtygarageguy lol that clears that up then. Cheers.

[@883WAYNE]

Thanks Matt... So a tappy valve, is a happy valve.

[@CommieHunter7]

That's what they say.

[@MarkOneMoto]

What an excellent video, that explained things beautifully, I was just wondering a few days ago why the clearance gets smaller...you just answered it brilliantly, thank you 👍

[@pikebobstar2033]

Sorted a mates old zzr600 which, was a non starter. Compression was v low and fuel was blowing back through the carb on compression stroke! Can't remember figures exactly but had to go down couple shim sizes before even got a gap! Turned out he hadn't had valves checked since 30k, the bike was on 59k! Surprised that hadn't caused seat damage but with correct clearance managed to get that cylinders compression within 10% of the others. He got rid rapped after that. Great explanation 👍

[@SatrioWibowo1995]

Never think about that before, always loving your content. Greetings from Indonesia🇮🇩🇮🇩🇮🇩

[@leftmorningstar6954]

they do a knocking sound if this happens< , when cold a hear hard knocking i don t know if it is the cam that maybe jumped a tooth or this ?

[@digger8180]

I used to have nightmares about Wire drawing of valves and their seats, I'm OK now, I don't even have the urge to take a log of the fridge temperatures anymore. Long walks help!

[@CollinMac96]

Off topic, but I have a question mate. Do you think, in general, fuel additives like sea foam and MMO are worth using for cleaning off carbon on the valves? I’ve always figured it’s a bit of snake oil since fuel already has additives in it.

[@dirtygarageguy]

We'll be ing some testing soon

[@CollinMac96]

@The Workshop awesome to here, looking forward to it

[@blind9376]

@@dirtygarageguy Have seen positive reports for Yamaha combustion chamber cleaner

[@thuglifescorpion]

@@dirtygarageguy It's a longer proces and not widely used, but I just installed water methanol injection again. This cleaned my EGR abused intake up like new on my car so why not on my motorcycle.

[@davefitzpatrick6879]

Hiya Matt, are you aware that your latest videos are really dark until you stick your big head into the line of the camera lens when it brightens up a bit

[@somborn]

Do a valve job with Isaac, you might end up in youtube rewind.

[@Nicko_1]

Can’t wait to see the comparison to the desmo clearances

[@taffrat3826]

Sometimes, I lie awake at night dreaming of my tip wearing... Now, you might ask how I can lie awake and also be dreaming but it's a secret and it does take a lot of practice. RE Himalayan for the win. Chur.

[@albertoj.mollinedo4116]

Hey Matt, question here, some people say that with port injection and especially with electronic throttle body. You get carbon deposit on the intake valve and intake port. How’s that posible. isn’t the valve supposed to be closed and the fuel doesn’t go anywhere near that part of the bike.

[@dirtygarageguy]

Not port injection but direct injection.

[@fuzzy1dk]

exhaust gas recirculation back into the intake. With direct injection the is nothing "washing" back of the intake valve like there is with port injection

[@nothanks3462]

Direct injection - timing (normally variable on modern stuff) and pcv system can let build up occur. Only a problem really for engines that do mostly short journeys, run shit fuel and oil and generally lack maintenance. Had vw 2.0TFSI engine with over 210,000 miles when sold, previous owner and I looked after it properly, never had an issue with intake valves. Other shit made from plastic with low quality rusted fasteners however......

[@reidspeed77]

Az always, gold. Timing t mark,I find my 2 vave runs cool if I set gap right at the very start of tdc about 2°before the t mark ,irun a massive cam ,am I an idiot?

[@Porsche996TT]

I just looked up my engine's valve clearance values and they are 0.10 to 0.15 on the intake and 0.20 to 0.25 on the exhaust (rocker arm single cam). I'm wondering why they're so big? What if I decreased the gap a bit? The engine is Renault K7M 1.6 8v

[@hassejohansson3617]

I like to set the clearance approx in the middle of the specks is that good?

[@impaledface7694]

I have a bike that had too tight of valve clearance. Bought it used supposedly was a track day trainer bike (yamaha srx 250). Rode it around, didn't realize till I got home that it felt like it had less power than my 125 scrambler. Found the exhaust valve clearance was way too tight. After the shim swap I swore the compression went up and it made it's full (24ish) hp. Now it's doing some other weird shit, but it's on the project back burner for now. Sometimes it's nice having hydraulic lifters, or easy access screw+locknut valves.

[@stephenfleming7056]

I thought I was playing safe and set the clearances to the upper limit on my 1200 Bandit, It sounded like a biscuit tin of nails. so I now set just off the min and check them regularly, its quite a short check interval for the Bandit anyway. Is there a risk of damage from having the clearances over the max, the valve or rocker would be contacting the cam further round and the profile with more force?

[@dirtygarageguy]

Just more noise and slightly more wear. It can cause problems with rockers, but we'll get into that

[@davidgruen7423]

I rebuilt the head on my $500 PT cruiser, the exhaust valve face looks like stairs.

[@davidchambers6346]

Proper off topic, but I respect your engineering background, knowledge and reasoned opinion, and I doubt you will ever do a vid on the subject so..... What are your thoughts on the niken?

[@dirtygarageguy]

I also did a test ride on one, but the sv died and I ended up in a field

[@dirtygarageguy]

As for thoughts, its a bike, thats worse than a normal bike. Its a gimmick to try and get none riders to ride

[@davidchambers6346]

@@dirtygarageguy thanks for opinion Matt much appreciated taking the time!

[@thealvaco]

This is why the 4 stroke mx bikers sometimes put oil in there petrol. To stop the valve wear. I think that's stupid. What do you think Matt?

[@dirtygarageguy]

Yes it's stupid.

[@thealvaco]

@@dirtygarageguy I shall quote the backstreet boys and say:" Tell me whyyy".

[@localenterprisebroadcastin5971]

This is why I love 2 cycle engines....reeds are much simpler 😂

[@brockett]

So is that amount of wear age related of is there anything the user could have done to prevent it?

[@dirtygarageguy]

Wear through use. We'll talk about this next.

[@TonMachielsen]

Does valve clearance have an noticeable effect on valve timing as well?

[@dirtygarageguy]

Not noticeable unless they're way off

[@TonMachielsen]

@@dirtygarageguy Thanks!

[@martinshaw4676]

Got some old valves in my garage that are no use to me maybe you could make use of them for a vid? There pretty well used and cracked titanium ones

[@dirtygarageguy]

Email me with pics

[@martinshaw4676]

Will do once finish work tomorrow

[@snafusnafu7409]

Hi from Scotland 💛💛💛💛💛🏴󠁧󠁢󠁳󠁣󠁴󠁿🏴󠁧󠁢󠁳󠁣󠁴󠁿🏴󠁧󠁢󠁳󠁣󠁴󠁿🏴󠁧󠁢󠁳󠁣󠁴󠁿🏴󠁧󠁢󠁳󠁣󠁴󠁿🏴󠁧󠁢󠁳󠁣󠁴󠁿🏴󠁧󠁢󠁳󠁣󠁴󠁿🏴󠁧󠁢󠁳󠁣󠁴󠁿

[@jamesstuart8271]

Barely rev my Zrx1200r above 2.5k - 3.0k rpm most of the time (most of its use in city plus I’m an old bugger) so I won’t need to check the clearances at Motocycle intervals - more like car mileage intervals 30k to 50k - not going to hit the valve seats so hard at lower (car range)rpms

[@thomaslemay8817]

Proper valve clearance is of the upmost importance to little clarence valve Burns too much the components beat themselves to death.

[@leandrolima1057]

Bro, every manual has upper and lower clearances and I never know which one is best. Also when using free flow exhaust how I have to adjust the valve? Nobody, in anywhere responded that yet..

[@dirtygarageguy]

Free flow exhause valve adjustment?

[@leandrolima1057]

@@dirtygarageguy thanks for replying, I meant free flow muffler, replacing stock exhaust.. But the main concern is which maker manual value should i take when adjusting: upper value or the bottom one. There are lots of videos how to, but none to explain which value is best. Your videos are great, sorry for the poor english, greetings from Brazil!

[@kyleskidmore3857]

Spot on

[@ticthedog9413]

👍 Great explanation

[@MsIvicao]

Excellent mate...tnx

[@danmanthe9335]

Damn I had the worst time figuring this stuff out last time I did the valves on my bike. Started over thinking it and it just got worse. Can you shed some light on the statement that certain (aluminum) heads shouldn't be lapped? I'd guess it's related to the hardening of the metal?

[@LinkinMcOwnage]

Titanium valves with special coatings must NOT be lapped because they lose the coating and wear excessively. The correct procedure is to cut the seats and if necessary replace valves. For anything that's older with just plain old steel valves then lap away.

[@dirtygarageguy]

m.kzbin.info/www/bejne/g2WYqKWnZbOplcU

[@danmanthe9335]

Well shit. Guess I could've lapped the valves. Now I've got suspicions that my valves aren't seating well enough

[@donr62]

Another consideration for clearances is that cams are quite sloppy in their journals compared to main and big end journals.

[@dirtygarageguy]

What?

[@donr62]

Check the specifications for cam journal clearances of a few engine models. They fit like dicks in a shirt sleeve.

[@dirtygarageguy]

And then there's thermal expansion...

[@andywilliams7510]

Q. Is there a single valve engine?

[@dirtygarageguy]

Yes. Loads of diesel 2 stroke engines are single valve

[@waynedl99]

@0:17 - that's not a valve.... THAT's a valve...

[@stephenmurphy2638]

Bet that gap lets a bit oil in to

[@dirtygarageguy]

The oil is already on the cam

[@troywee4774]

cool!

[@gilbertreeves2084]

Matt I liked the video...especially after you erased the erection going on there..!

[@snafusnafu7409]

Just finished stripping my engine

[@snafusnafu7409]

@Mother Algorithm going put in a big pressure cooker to clean everything

[@snafusnafu7409]

Yeah it's away now

[@adivarso8175]

1

[@adivarso8175]

@Mother Algorithm WE might just do that ;)

[@who_is_john_galt]

I actually once saw a valve that had been worn down so much that the edge of it was sharp. :()

[@Matt-we7si]

nothing a bit of body filler cant sort out matt

[@H-M-78]

2