Calculated risk - Valve clearances and Spark plug

1476 Views 19 Replies 10 Participants Last post by Hobbyman2007, 3 mo ago

Lupolee

Discussion Starter · 3 mo ago

Before I explain my scenario I though it best to say I have read a bit about valve clearance checks and spark plug changes on this wonderful website. However, my question to this forum is whether any one else has done what I am considering?

The 32k miles checks/changes are now due, so I spoke to my dealer (was Honda for years but now with another brand) he is one of the few in the industry I trust. He asked me if I was keeping the bike (yes) and then proceeded to tell me that if the bike sounds ok (fires up from cold and not rattling any more than normal) it’s not worth checking the and replacing the plugs. He said the time and money (especially in parts if the leads break etc) is not worth it when it’s running good.

I trust his judgement, he will of seen a few hundred AT’s go through the shop in his time but it feels counterintuitive to me to skip this maintenance? I did have the valves checked at 16k and all were within tolerances, I don’t ride the bike super hard every where (although I do once in a while), and I change fluids every year so maintain some mechanical sympathy.

Have you done what my dealer is saying to do and if so how’s it going since? Or are you 💯 against the idea for valid reasons (not just because Honda say so)?

Thanks,
Lee

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AT-Dragon

· #2 · 3 mo ago

It goes with the old saying “ if it ain’t broke, don’t fix it “
I’ve heard from plenty of bikers and it’s been the same thing , “had (or did) a valve check and it was good” once I heard it was off, but that was a barely over spec’s and a AMC-HD so…
LOL, I’d say actually I know more ppl that have done it as an excuse to polish the ports and/or change the cam, then they were actually worried about the clearance..

Reactions: 2

paulbaker428

· #3 · 3 mo ago

Lupolee said:
Before I explain my scenario I though it best to say I have read a bit about valve clearance checks and spark plug changes on this wonderful website. However, my question to this forum is whether any one else has done what I am considering?

The 32k miles checks/changes are now due, so I spoke to my dealer (was Honda for years but now with another brand) he is one of the few in the industry I trust. He asked me if I was keeping the bike (yes) and then proceeded to tell me that if the bike sounds ok (fires up from cold and not rattling any more than normal) it’s not worth checking the and replacing the plugs. He said the time and money (especially in parts if the leads break etc) is not worth it when it’s running good.

I trust his judgement, he will of seen a few hundred AT’s go through the shop in his time but it feels counterintuitive to me to skip this maintenance? I did have the valves checked at 16k and all were within tolerances, I don’t ride the bike super hard every where (although I do once in a while), and I change fluids every year so maintain some mechanical sympathy.

Have you done what my dealer is saying to do and if so how’s it going since? Or are you 💯 against the idea for valid reasons (not just because Honda say so)?

Thanks,
Lee

Lupolee said:
Before I explain my scenario I though it best to say I have read a bit about valve clearance checks and spark plug changes on this wonderful website. However, my question to this forum is whether any one else has done what I am considering?

The 32k miles checks/changes are now due, so I spoke to my dealer (was Honda for years but now with another brand) he is one of the few in the industry I trust. He asked me if I was keeping the bike (yes) and then proceeded to tell me that if the bike sounds ok (fires up from cold and not rattling any more than normal) it’s not worth checking the and replacing the plugs. He said the time and money (especially in parts if the leads break etc) is not worth it when it’s running good.

I trust his judgement, he will of seen a few hundred AT’s go through the shop in his time but it feels counterintuitive to me to skip this maintenance? I did have the valves checked at 16k and all were within tolerances, I don’t ride the bike super hard every where (although I do once in a while), and I change fluids every year so maintain some mechanical sympathy.

Have you done what my dealer is saying to do and if so how’s it going since? Or are you 💯 against the idea for valid reasons (not just because Honda say so)?

Thanks,
Lee

Lupolee said:
Before I explain my scenario I though it best to say I have read a bit about valve clearance checks and spark plug changes on this wonderful website. However, my question to this forum is whether any one else has done what I am considering?

The 32k miles checks/changes are now due, so I spoke to my dealer (was Honda for years but now with another brand) he is one of the few in the industry I trust. He asked me if I was keeping the bike (yes) and then proceeded to tell me that if the bike sounds ok (fires up from cold and not rattling any more than normal) it’s not worth checking the and replacing the plugs. He said the time and money (especially in parts if the leads break etc) is not worth it when it’s running good.

I trust his judgement, he will of seen a few hundred AT’s go through the shop in his time but it feels counterintuitive to me to skip this maintenance? I did have the valves checked at 16k and all were within tolerances, I don’t ride the bike super hard every where (although I do once in a while), and I change fluids every year so maintain some mechanical sympathy.

Have you done what my dealer is saying to do and if so how’s it going since? Or are you 💯 against the idea for valid reasons (not just because Honda say so)?

Thanks,
Lee

My bike has 20k on it, never been checked. I ride it fairly hard a lot of the time. When it went in for the 16k service my stealer asked if it started and ran okay, yes was the answer, and he suggested leaving out the valve check. If I still have the bike at 32k I'll reconsider, but abide by the same philosophy. And the plugs? I've heard they're good for 100k!

Reactions: 3

Ghostrider.1127

· #4 · 3 mo ago

Valves check at 16k (or 24k KM) is most of the times pretty useless , @32000 (or 48000) most of the times on the exhaust side ( where shims are not used) need adjust , than replace plugs is a must to keep the bike reliability

Reactions: 5

DoubleThumper

· #5 · 3 mo ago

I recently read a very similar discussion on the Honda PCX Forum.

Getting to the plug and valves is a couple times more inconvenient compared to the Africa Twin (hard to believe, but that is the Honda way). The vast majority of owners found gaps within tolerance. In addition, most Honda dealerships won't even tear down the bike to do the work. It appears they using listening (sound) techniques to determine is a valve adjustment is required. Unless the owner insists they want a manual teardown, the garage appears to use sound to make the judgement.

(yeah)

Reactions: 4

Ghostrider.1127

· #6 · 3 mo ago

Pcx valve job , is another chitty job , as you have to teardown all the rear parts
Also from the 1th gen PCX to the last gen. , those get 4 different engines . All this engines have different needs and specs. if the use is over 90% only town ride , every 5000/10000 km check the valves is a good idea

Reactions: 1

DoubleThumper

· #7 · 3 mo ago

" ... shhhhh, shhhh, ... quiet, quiet. I am listening to the valves. Mmmmmm, yea, ... yes, ... yup. Hershel - where is Hershel? ... Wherever you are, tell the client the intake is 0.01 mm beyond the short side limit."

Reactions: 5

Ghostrider.1127

· #8 · 3 mo ago

Till you can hear the valves ticking it is ok , they still have play and are not sitting open with the risk of burn . Too much play will reduce performance , too less will reduce performance and cause damages ( incorrect play normally . Shims type , are normally prone to INCREASE the free play over 55000/70000 km ; screw-tappets type MOST of the times are prone to Increase the free play even after 20000/30000 km) .

Also , valves ,that control the air/fuel flow and exhaust gases are one of the most abused parts in the entire motor . Like spark plugs are ....

Must add , even if it sound OK have too much play on the distribution
please consider :

Higher clearance
The valve will open later and close sooner
The max lift of the valve will decrease
Problematic extraction of exhaust gas
Repeated collision can cause damage to the valve stem

and other way round

Lower clearance
The valve will open sooner and close later
You may observe air leaks in the combustion chamber, leading to less available air for proper combustion.
The power and performance of the engine will decrease
MPG will decrease
The temperature of the exhaust will increase
In some scenarios, the valve could stay open for an extending period of time, causing decrease in the engine’s compression pressure.

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Lupolee

Discussion Starter · #9 · 3 mo ago

Cheers folks, I think you summarise my thoughts on it all. I have the “usual” ticking noise above the bellow of the exhaust but that hasn’t changed much at all and in fact is more likely me getting used to the engine than the noise increasing - certainly not tappety if that is such a word?

I think I will get round to checking the valves and doing the plugs later this year and not worry too much about doing it EXACTLY on 32k.

Reactions: 2

Autonomity

· #10 · 3 mo ago

My Suzuki wee had about 60k km without any valve checking done and only the exhaust side was "grossly" out of spec. Like Ghostrider said, at 48k you might see some movement on the exhaust side, AT has tappets to adjust exhaust side.

Usually the first check is wise to do, after that it's whatever really. That said heatcycling (lots of shorter rides) might be more relevant than mileage in a case like this. If you're revving the crap out of the bike or asking a lot of it you'll also see exhaust side creep a bit faster. However on most stuff our Japanese friends are a little conservative/overly safe, I've also ran the same oil in the wee for like 20k with no issues.

Reactions: 1

Lupolee

Discussion Starter · #11 · 3 mo ago

Autonomity said:
My Suzuki wee had about 60k km without any valve checking done and only the exhaust side was "grossly" out of spec. Like Ghostrider said, at 48k you might see some movement on the exhaust side, AT has tappets to adjust exhaust side.

Usually the first check is wise to do, after that it's whatever really. That said heatcycling (lots of shorter rides) might be more relevant than mileage in a case like this. If you're revving the crap out of the bike or asking a lot of it you'll also see exhaust side creep a bit faster. However on most stuff our Japanese friends are a little conservative/overly safe, I've also ran the same oil in the wee for like 20k with no issues.

Thank you. I tend to treat my bikes like I treat my self - give it time to warm up, use it regularly, thrash it every now and then, and clean it when it’s dirty. 😆

Reactions: 4

Lee R

· #12 · 3 mo ago

Other than my Chinese bike and my Moto Guzzi with screw adjusters none of my shim under bucket bikes have needed a valve adjustment in the timeframe I owned them. My Triumph Tiger 1050 was in spec until I sold it at 48k miles.

I'd expect the AT to be in spec to at least 30k and then need the screw adjusters on the exhaust side to be adjusted. I'll probably check mine at recommended interval myself but I wouldn't pay for it that soon.

If you did valve checks at 16k miles that's like over 6k in routine maintenance for 100k miles. Might as well just buy a new engine.

BRING BACK HYDRAULIC VALVES HONDA!

I was very very very close to buying the Pan America for that specific reason, and may still. I hate valve checks. It's 2023.

Reactions: 1

DoubleThumper

· #13 · 3 mo ago

Lee R said:
Other than my Chinese bike and my Moto Guzzi with screw adjusters none of my shim under bucket bikes have needed a valve adjustment in the timeframe I owned them. My Triumph Tiger 1050 was in spec until I sold it at 48k miles.

I'd expect the AT to be in spec to at least 30k and then need the screw adjusters on the exhaust side to be adjusted. I'll probably check mine at recommended interval myself but I wouldn't pay for it that soon.

If you did valve checks at 16k miles that's like over 6k in routine maintenance for 100k miles. Might as well just buy a new engine.

BRING BACK HYDRAULIC VALVES HONDA!

I was very very very close to buying the Pan America for that specific reason, and may still. I hate valve checks. It's 2023.

Hydraulic valve lifters and shaft drive. Bring back the old Honda high tech,

Sweet speak.

Shadowjack

· #14 · 3 mo ago

If you can hear he valves, that's not necessarily a bad thing. That's telling you they're going down onto the seats. If they're quiet, you can never be sure they're not too tight, and they might be leaking a little. But the classic symptom of too-tight valves is hard starting. Which is why they asked you about it.

Reactions: 1

Lee R

· #15 · 3 mo ago (Edited)

DoubleThumper said:
Hydraulic valve lifters and shaft drive. Bring back the old Honda high tech,

Sweet speak.

Right?

I was t-h-i-s close to buying a Pan America because of Hydraulic Valves. I actually was on preorder for them and Harley didn't contact me until way later and tried to apologize but I was already annoyed and bought the AT.

Literally would have that bike in my garage right now had they contacted me in time.

Having done a lot of valve checks, I detest them. Waste of my time or money or both. I used to commute 25k miles a year by bike, 2 checks a year on a Triumph Tiger 1050, which is 12k intervals. I HATE THEM (valve checks, not Triumph, the Tiger was sweet, but I sold it early, because of those intervals)

Next bike, MG Stelvio with super easy valve covers exposed and screw adjusters, because I hate shim under bucket checks.

Nearly PA for some reason.

Honda are you listening?

I may ditch the AT way early for the same reason as the Tiger, honestly it's the only thing about it that would cause me to get rid of it. Seriously. I.hate.them.

I'm not joking when I think you might as well never check and if the engine goes, it goes. Just replace the top end, what's the cost of that vs 3-4 valve checks?

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Hobbyman2007

· #16 · 3 mo ago

Valves never get loose. The valve seats get pounded in and the valves get tight to the cam. And in most cases is the exhaust side from the heat, the intake valves will lose the tolerance mainly due to dirty air flowing through them. This causes the valves to be open and reducing compression. This notion that you will hear ticking is nonsense, what you will hear is the shim or valve stem riding on the cam for the entire rotation and you would need a stethoscopes and real good hearing. I’m a professional mechanic and have been earining a living doing so for the last 25 years. I check my valve adjustments only when the engine is hard to start. You’ll notice more when hot as the tolerances are less from heat expansion.

Reactions: 5

Lupolee

Discussion Starter · #17 · 3 mo ago

Hobbyman2007 said:
Valves never get loose. The valve seats get pounded in and the valves get tight to the cam. And in most cases is the exhaust side from the heat, the intake valves will lose the tolerance mainly due to dirty air flowing through them. This causes the valves to be open and reducing compression. This notion that you will hear ticking is nonsense, what you will hear is the shim or valve stem riding on the cam for the entire rotation and you would need a stethoscopes and real good hearing. I’m a professional mechanic and have been earining a living doing so for the last 25 years. I check my valve adjustments only when the engine is hard to start. You’ll notice more when hot as the tolerances are less from heat expansion.

Cheers boss. What causes the increase in ticking noise you hear so often on a higher mileage engine?

Ghostrider.1127

· #18 · 3 mo ago (Edited)

Hobbyman2007 said:
I check my valve adjustments only when the engine is hard to start.

tells us where is your workshop , so no one can make the mistake

Reactions: 1

don67

· #19 · 3 mo ago

Hobbyman2007 said:
I’m a professional mechanic and have been earining a living doing so for the last 25 years. I check my valve adjustments only when the engine is hard to start.

In your experience, what is the risk of engine damage caused by not checking clearance?

As a DIYer I can't imagine spending hundreds of dollars every 2-3 years for valve checks. But I'm not so crazy about tearing down a perfectly good bike, either.

Hobbyman2007

· #20 · 3 mo ago

I have seen many instances of valves contacting pistons , none of which were from valve clearances being out of spec. Valve float being the cause every time, caused by holding high rpm for extended periods. Best example are MX bikes , prone to this problem. There is no harm per se for having tight valves, hard starting , poor performance are the typical signs. Having loose valves is a whole other story.
if you hear you valves ticking as mentioned in a previous post, this is usually from hydraulic lifters loosing their oil. Shim under bucket or screw type adjusters that get noisy are from the cam journal bearings , cam journal wear or screws backing off. Not valve wear.
I don’t work in the motorcycle industry , don’t worry about what shop I’m in. I travel and repair heavy equipment. The pay is much better. And I don’t have to deal with know it all private owners.

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