Valve clearance

[Tex 36,817]

12 hours ago, Graham NZ said:

At least the NC screw and locknut tappets can be serviced by owners if they want to.  With shimmed systems a whole set of shims is required unless a lot of mucking about is undertaken - measure the clearances, remove the shims if adjustment is needed, acquire new shims of the appropriate thickness, refit and remeasure everything and hope you got it all correct.

 

But, on the other hand, shims tend to hold their adjustment much longer..

[SteveThackery 3,090]

1 hour ago, Tex said:

 

But, on the other hand, shims tend to hold their adjustment much longer..

 

Ah, I'm glad you said that because I'm trying to find out why.  Having worked on both types, I can't see any reason why a shim system should need adjusting any less often than a screw/locknut system.

 

After all, it's usually the valve bedding into the seat that causes the gap to close up, which has nothing to do with the adjustment method.  I don't know what causes the gap to open up (on a modern engine, I mean), but I doubt it's got anything to do with how the gap is adjusted.

 

So, gang:  firstly, is it definitely true that shim systems need adjusting less often?  Do we have any data on this?  Secondly, if that is true, then why?  What is the mechanism by which the screw/locknut system drifts more than the shim system?

[Graham NZ 1,186]

I've always thought that shims hold adjustment for longer but more importantly stand high revs better.  Not only is the NC engine low revving but most of the time it is operating nowhere near it's rev limit.  Given the choice with an NC I'd vote for screw and locknut.

[larryblag 14,236]

On 9/9/2018 at 11:50, Spindizzy said:

We have hydraulic adjusters on plane engines dating back to the fifties. Cant see why something cant be designed for  bike. Just an opinion, maybe space/price is an issue.

Harley Davidson have had hydraulic "tappets" for years now

[klrman 560]

30 minutes ago, SteveThackery said:

 

Ah, I'm glad you said that because I'm trying to find out why.  Having worked on both types, I can't see any reason why a shim system should need adjusting any less often than a screw/locknut system.

 

After all, it's usually the valve bedding into the seat that causes the gap to close up, which has nothing to do with the adjustment method.  I don't know what causes the gap to open up (on a modern engine, I mean), but I doubt it's got anything to do with how the gap is adjusted.

 

So, gang:  firstly, is it definitely true that shim systems need adjusting less often?  Do we have any data on this?  Secondly, if that is true, then why?  What is the mechanism by which the screw/locknut system drifts more than the shim system?

Steve, you disturb my Karma. I amble through life without a care in the world until someone (and you're good at it) makes me stop and think. I haven't got a clue what the answer is, but it's a bloody good question. I've always wondered if someday, someone, will reinvent the wheel. Well, you get my vote. Keep 'em coming

[Tex 36,817]

28 minutes ago, Graham NZ said:

I've always thought that shims hold adjustment for longer but more importantly stand high revs better.  Not only is the NC engine low revving but most of the time it is operating nowhere near it's rev limit.  Given the choice with an NC I'd vote for screw and locknut.

 

Completely agree, Graham. On all counts.

 

Steve, I don’t have a definitive answer for you but I believe Graham has something when he mentions the ability of shims to better stand high revs.

 

Factual data? Well Yamaha have a first valve clearance check (on some/most of their shim engines) at 28k miles. I’m betting that nobody can come up with a manufacture who says the same for a screw/locknut system?  

[SteveThackery 3,090]

37 minutes ago, klrman said:

I've always wondered if someday, someone, will reinvent the wheel. Well, you get my vote. Keep 'em coming

 

Actually, I've got a slightly challenging thought about this!  I put it to you that the "wheel" per se didn't really need inventing, because it's just a thin slice cut off the end of a roller.  Ancient Man (even ancienter than Rocker) will have discovered the value of tree trunks as rollers for moving heavy things, rather than invented them, because they are everywhere trees grow.

 

Rather, what needed inventing - and in retrospect was a great intellectual leap - was the hub.  That's what lets us get the function of a roller without having to collect the damn thing every few feet and carry it back up to the front of the sled.  

 

So, instead reinventing the wheel, shouldn't we be reinventing the hub?

 

Edited September 12, 2018 by SteveThackery

[larryblag 14,236]

1 hour ago, SteveThackery said:

 

Ah, I'm glad you said that because I'm trying to find out why.  Having worked on both types, I can't see any reason why a shim system should need adjusting any less often than a screw/locknut system.

 

After all, it's usually the valve bedding into the seat that causes the gap to close up, which has nothing to do with the adjustment method.  I don't know what causes the gap to open up (on a modern engine, I mean), but I doubt it's got anything to do with how the gap is adjusted.

 

So, gang:  firstly, is it definitely true that shim systems need adjusting less often?  Do we have any data on this?  Secondly, if that is true, then why?  What is the mechanism by which the screw/locknut system drifts more than the shim system?

On the CB1100 forum they're keeping a very useful post going where owners are encouraged to report the findings (either DIY or dealer work). The clearances as found are posted for each valve then the adjusted values too. Very, very useful.

 

One member has posted something like:

12,000 miles - within tolerance (no adjustment required)

24,000 miles - within tolerance (no adjustment required)

50,000 miles - within tolerance (no adjustment required)

He finishes by saying at 60,000 miles he has no intention of ever going near them again.

 

Still, they are shim-under-bucket. My own feeling is that with the NC being so simple (relatively speaking) I would have no hesitation in getting them done as per Honda's recommendation.

If i'd kept my NC I'd have definitely done them myself. Although I believe it's possible without disturbing the rad plumbing, like Trisaki says you might as well take the opportunity to change the coolant at the same time?

 

 

[larryblag 14,236]

On 9/9/2018 at 18:39, klrman said:

However, the one I don't understand in this day and age of fuel injected bikes is spark plug replacement. I'll probably provoke some disagreement on this but in my opinion if a bike will pull hard at 3/4 revs and more without misfiring, then leave well alone. Cars and bikes alike. 

"Colin" the Mitsubishi Colt had a few invoices in the bumf when I bought it. Previous owner had paid £16 each for iridium spark plugs. With an expected life of >60k miles I won't be changing them any time soon either.

[larryblag 14,236]

On 9/9/2018 at 19:08, Rocker66 said:

I just remember my 4 times table from primary school😀😀

Yup. I did them too. Here's how I remember it:

 

4, 8, 12 erm... a lot

[larryblag 14,236]

On 9/10/2018 at 15:17, DaveM59 said:

I changed the oil on my Diesel Fiesta a few weeks ago and also got the impression from the difficulty I had removing the oil filter, plus the cruddy gunged up state it was in that it had never been touched for a long time maybe even the whole 40,000 miles. It was supposed to have been serviced when I bought it from a main dealer last year and although when I dipped the oil it look clean-ish, they definitely didn't change the filter.

Not sure whether to take the Forza back at 600 miles for the first service or just do it myself as it may possibly be next spring before I put that many miles on it. If it's free I might - didn't ask! After that it will be DIY I think.

I myself do have trust issues too. I've been stung a few times - mainly with cars.

You can read on here so many examples of sloppy work - too much oil, bowstring chains, dubious lack of understanding of Honda's own info etc etc.

 

I'd take a trusted independent over a main dealer any time I'm afraid. And when you've found a good one - keep him sweet. It's well worth it.

Edited September 12, 2018 by larryblag
Wait! more to say (that's me)

[Graham NZ 1,186]

Spark plugs.  When you look at them these days of FI and unleaded fuel, they never seem to show any significant electrode wear so I wonder why we need to change them either.  Still, engines seem to run more sweetly when new ones have been installed, just like after a good body polish.

[temp 359]

I want to know more about how to get a good body polish.

[SteveThackery 3,090]

20 minutes ago, Graham NZ said:

Still, engines seem to run more sweetly when new ones have been installed, just like after a good body polish.

 

Even more weird: the engines on my bikes run at their sweetest on their way back from a successful MOT test.  AND it improves the handling.....

[Guest machinman]

A bike always rides better after you've cleaned it too🤣🤣

[larryblag 14,236]

1 hour ago, SteveThackery said:

 

Even more weird: the engines on my bikes run at their sweetest on their way back from a successful MOT test.  AND it improves the handling.....

Do you know, I've noticed that too 

[kayz1 2,928]

12 hours ago, SteveThackery said:

 

Actually, I've got a slightly challenging thought about this!  I put it to you that the "wheel" per se didn't really need inventing, because it's just a thin slice cut off the end of a roller.  Ancient Man (even ancienter than Rocker) will have discovered the value of tree trunks as rollers for moving heavy things, rather than invented them, because they are everywhere trees grow.

 

Rather, what needed inventing - and in retrospect was a great intellectual leap - was the hub.  That's what lets us get the function of a roller without having to collect the damn thing every few feet and carry it back up to the front of the sled.  

 

So, instead reinventing the wheel, shouldn't we be reinventing the hub?

 

So the guy we should be applauding is the guy who invented the Axle to go with the thin sliced tree trunk.

Lyn.

[MikeBike 5,005]

6 hours ago, kayz1 said:

So the guy we should be applauding is the guy who invented the Axle to go with the thin sliced tree trunk.

Lyn.

He introduced friction where the axle goes through when there weren't any rubbing surfaces with the log.  The rolling logs analogy is much.more suited to the ball or roller bearing.

[embee 7,288]

I'll contribute when back home on the PC, can't be bothered typing on the phone. It's not a simple clear cut issue ref direct attack vs rocker vs finger follower.

[larryblag 14,236]

One of the best inventions ever has got to be gravity - surely? 

No wonder Isaac was knighted for it. Gravity is so important. I see examples of its use every single day. On my way to work this morning, people were outside Aldi waiting for it to open - gravity 

As I cycled along the canal path there were other cyclists coming the other way and I'll bet some of them were using gravity too? To be honest though I could not have told you which ones. 

Now they do gravity in so many different colours though, it's getting difficult to decide which one to go for. 

Edited September 14, 2018 by larryblag
Suitable Emoticons

[fred_jb 10,264]

On 12/09/2018 at 12:26, SteveThackery said:

 

Actually, I've got a slightly challenging thought about this!  I put it to you that the "wheel" per se didn't really need inventing, because it's just a thin slice cut off the end of a roller.  Ancient Man (even ancienter than Rocker) will have discovered the value of tree trunks as rollers for moving heavy things, rather than invented them, because they are everywhere trees grow.

 

Rather, what needed inventing - and in retrospect was a great intellectual leap - was the hub.  That's what lets us get the function of a roller without having to collect the damn thing every few feet and carry it back up to the front of the sled.  

 

So, instead reinventing the wheel, shouldn't we be reinventing the hub?

 

Well, while I applaud your efforts for precision in terminology, I would contend that the difference between a roller and wheel is precisely that the concept of the wheel, as we all understand it, inherently includes a hub - can you think of any example of a wheel that doesn't have a hub?

 

So, I would say that there is no need to reinvent the reinventing the wheel phrase! 😁

[MikeBike 5,005]

16 minutes ago, fred_jb said:

can you think of any example of a wheel that doesn't have a hub?

 

 

[SteveThackery 3,090]

27 minutes ago, fred_jb said:

Well, while I applaud your efforts for precision in terminology, I would contend that the difference between a roller and wheel is precisely that the concept of the wheel, as we all understand it, inherently includes a hub - can you think of any example of a wheel that doesn't have a hub?

 

So, I would say that there is no need to reinvent the reinventing the wheel phrase! 😁

 

Phew!  MikeBike comes to the rescue.  

[fred_jb 10,264]

24 minutes ago, MikeBike said:

Sorry guys, nice try but that is tracked vehicle, not a wheeled one!

[Andy m 23,502]

On 09/09/2018 at 19:02, temp said:

Frequent oil and filter changes are the best to do for longeviety.

Well done!

Swings and roundabouts as always. The drain plug thread is worn by the change (alloy thread with a steel plug is poor and many are stripped by garage monkeys) and there is a period where the oil pump primes. At some low number of miles you are doing more harm than good. Then there is a range where you are just wasting oil and damaging the environment. Then there is a correct period, then one where the engine is wearing more than it needs because the oil is worn out. All oil analysis I've ever seen from fleets suggest the manufacturers never risk getting close to the wear zone. The only bike data I've seen was for a Weestrom in the US. The Suzuki interval at 4000 was in the waste/environmental damage zone. 12000 was a safe interval. 

 

All screw threads faced with vibration turn so I can believe shims are better. I have no proof and would suspect the difference is so marginal you may as well have the ease of screw threads. Faced with screws I know I can finish the job the same day. Faced with shims, I face having to order parts, giving the dealer another advantage. 

 

I have seen sparkplug failures. I suspect these are such cost sensitive item that you are changing them in case you have one that is wearing quickly. 

 

I will change my oil at the Honda interval so I can stamp the book and tick a box for the salesman who will be expected to make me an offer on it in 30 months/20000 miles. If the engine sounds fine the valves will be left alone as "longevity" is not my problem. 

 

Andy