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agent provocateur
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Discussion Starter · #1 ·
Ok...let me first start off by saying I am NO babe in the woods as it would be when it comes to engines and so on. I have worked with many types of engines in my day, also I am a Millwright.

Now here is the question that has me really wondering. I have the full shop manual for my bike the ( 2010 GL1800 ). Now it says to release the timing chain when checking the valve clearences....and failing to do so will result in the readings not being right. Say what...?????

Why does it run with a chains loose...I do not think so...so whatever the gap is, that is the gap that there will be when its running...as I see it. I see it as with the chain done up ready to run, that is whats truely reflect as being a true gap when running....right ?

Someone explain this to me...as I do not see the logic in this. Am I missing something here...?
 

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I agree with you, no idea why you would need to do that. We don't do it on Honda cars.
 

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agent provocateur
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Discussion Starter · #3 ·
I see it this way...whenever position the cam is in with the chain on and done up right, that is how its going to be running in real life. So if one would loosen the chain and the gap lets say changes...then that's not going to reflect the gap its going to have when its running.

And the way I see it is....if the tension on the cam is big enough to change the gap enough to matter then you have a hell of a lot bigger problems then just the gap I would say...!

So I wrote here to ask if ANYONE can give me just one logical reason WHY I should loosen it....just one that I can wrap my head around it that has some logical reason.

And last of all...if you loosen it, then whats the point in trying to line-up the marks on the crank....there would be so much slack that those marks with be almost meaningless.

:confused:
 

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And last of all...if you loosen it, then whats the point in trying to line-up the marks on the crank....there would be so much slack that those marks with be almost meaningless.

:confused:[/QUOTE]

Actually no, the chain will not be loose enough to disturb the timing enough to matter. There are several degrees of rotation where the cam is in position close enough to check the clearance.
 

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agent provocateur
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Discussion Starter · #5 ·
I have been read and re-read all that it has to say on the valves everything from checking them to replacing the shims to get the right gap. And you know what I seem to come up with? That its a typo of sorts, in that to loosen the chain to remove the cam to get to the shims you need to replace. This is the ONLY logical thing I seem to come to each and every time.

As I said if someone can show my the logic behind slacking of the chain, I am all ears...!
 

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Piaggio MP3, was 02 GL1800
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I would not loosen them.
That has to be a bad misprint in that manual.
 

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It is not a typo...it is recommended shop procedure. If you talk to Honda service reps or tech line people, they will tell you it is necessary for accuracy. On the other hand, these are 'by the book' people.

Out of curiosity, I've actually inspected the same bike both ways and couldn't find any significant difference.
 

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agent provocateur
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Discussion Starter · #8 ·
It is not a typo...it is recommended shop procedure. If you talk to Honda service reps or tech line people, they will tell you it is necessary for accuracy. On the other hand, these are 'by the book' people.

Out of curiosity, I've actually inspected the same bike both ways and couldn't find any significant difference.
I have not opened it up yet...thats coming soon..! Its my winter project for the bike to work on it and get it ready for spring and a new riding season. The way I see it, you might get at the very most a .0005 to .001 differance...at the most. But even if there was a differance...would you not want to get a read of what its like in the read world....the way it is when its ready to run...?
 

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I wouldn't worry about it much since there is quite a bit more tolerance allowed in the direct cam over valve set up than a rocker arm valve train.
 

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And there's less moving parts to wear. Really, it's pretty rare to have to do any shimming. I've been working on GL1800s since 01 on a fairly regular basis...enough to have seen a pretty decent representative sample of things that can go wrong. I've yet to see any issues caused by valve clearance. I've shimmed one lifter in that time that was out by a bit more than .001. If I did find some clearances that were way off the first thing I'd do would be to double check the crank pos (to make sure I had in the right place). If it wasn't a mistake and the clearance was way out of spec...I'd suspect a wear problem with valve, seat, or lifter. I consider the valve train on 1800s bulletproof. I've done more transmission work than lifter shimming if that tells you anything.
 

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agent provocateur
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Discussion Starter · #11 ·
While it may or may not require adjustment on some it's more of a peace of mind to know that everything is alright. As well I like to have values a little on the looser side so if the specs call for say .009 clearance I like to have a .010 a little ticking sound is just fine by me, its when there is no sound that gets me up tight. As well as that I want to do a compression test as well...and log that in my records for this bike. I guess I am real stickler for details in many ways, use to work with aircraft for many years and if it was not perfect to my liking...I would not sign off on it, it stayed grounded till it was just right. That mind set has been with me long before I got into working with aircraft and that carrys over to my bike as well.

My old bike which was a Honda Shadow after about 4,000 Km's or something like that I took it in to have the valves clearances checked. Good thing I did when I did as there was one valve that had ZERO ( 0.000 ) clearance on it and all the others where near or nearing zero as well...! Then about a year later I did the valves myself on that bike and I set them to .002 over the max and that is how it ran to the day I sold it some 5 or so years later with something like 98,000 on the clock. And never had a problem with it other then picking up dirty gas one day that really did a number on the carb. My mistake in picking up gas just as they where finishing up filling the gas stations tanks...! Had to ride home with the choke full on just to keep it running...thats how clogged up it had become. The float bowl...you should have seen the pile of crap there was in there...! What a mess.
 

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As well I like to have values a little on the looser side so if the specs call for say .009 clearance I like to have a .010

I go for the tighter side myself, a little more cam duration for the best possible performance. And as long as there is any clearance it is not going to hurt it. Once the valve train has been broken in they will likely never get any tighter.
 

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agent provocateur
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Discussion Starter · #14 ·
As well I like to have values a little on the looser side so if the specs call for say .009 clearance I like to have a .010

I go for the tighter side myself, a little more cam duration for the best possible performance. And as long as there is any clearance it is not going to hurt it. Once the valve train has been broken in they will likely never get any tighter.
And how many Km's or Miles is considers " broken in " .... ?
 

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And how many Km's or Miles is considers " broken in " .... ?
Can't say exactly but well before the first scheduled clearance check.
 

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Nice thread guys.

I agree with all the comments, as I do my own checking. With 76K and checked by the book (w/o loosening the chain adjuster) all values are in line on the loose side. Did not notice any change from 40K.

I watched a dealer checking an 09 GW w/o loosening the chain too as does my shop. I check but will have the local independent shop do the shim work.

Happy Thanksgiving & Christmas.
 
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