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Offline syn

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Valve Clearances
« on: 13 November, 2009, 04:00:37 PM »
Hi,

I'm planning on measuring the valve clearances on the bike so I've been reading around. It seams Hornets and CBFs have a Cam Chain Tensioner Adjuster jutting out from the engine casing. The manual reports that this needs to be locked into position with a special tool/key before the clearances can be measured. This is described in both the Haynes manual and the Honda workshop manual. Is this step really necessary?

I've read a couple of manuals for other bikes (CBR600RR and SV650) that don't have this adjuster and they require no action to be taken regarding the cam chain while checking the valve clearances. So what's the deal with this design?

Wise words appreciated.

One on the road's worth two in the shed... and hedge for that matter.

Offline Bifferman

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Re: Valve Clearances
« Reply #1 on: 13 November, 2009, 04:14:28 PM »
Read Fred's brilliant article on checking the valve clearances;

  http://www.fireblader.dk/index.htm

Andy

 :149:

Offline Jumbo

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Re: Valve Clearances
« Reply #2 on: 13 November, 2009, 04:29:34 PM »
My understanding is that you don't need to  lock the chain tensioner for checking the valve clearances.
BUT>>> if you remove the cams to change shims, then you must lock the tesioner to stop it trying to tension a very loose chain while the cams are off. If the tensioner travels all the way in you must take it off to  reset it... Just an extra job you can avoid by locking the mechanism.

But like the man says, you better get more info from Fred's article and read the service manual. Looks straight forward enough for those raised on Mechano  :047:.
Jumbo
You’ve got to be very careful if you don’t know where you are going, because you might not get there.
Yogi Berra

Offline Bifferman

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Re: Valve Clearances
« Reply #3 on: 13 November, 2009, 04:33:15 PM »
*Originally Posted by Jumbo [+]
My understanding is that you don't need to  lock the chain tensioner for checking the valve clearances.
BUT>>> if you remove the cams to change shims, then you must lock the tesioner to stop it trying to tension a very loose chain while the cams are off. If the tensioner travels all the way in you must take it off to  reset it... Just an extra job you can avoid by locking the mechanism.
Jumbo

 :028:, I wondered why as well.

 :031:

Andy

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Offline badapple

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Re: Valve Clearances
« Reply #4 on: 13 November, 2009, 08:03:11 PM »
*Originally Posted by Jumbo [+]
My understanding is that you don't need to  lock the chain tensioner for checking the valve clearances.
BUT>>> if you remove the cams to change shims, then you must lock the tesioner to stop it trying to tension a very loose chain while the cams are off. If the tensioner travels all the way in you must take it off to  reset it... Just an extra job you can avoid by locking the mechanism.

  :047:.
Jumbo

You can release the tension with a screwdriver once the cap is removed by turning clockwise, but without the tool you need another hand to hold it in place. If you don't release the tension it makes it more difficult to remove the cam sprockets as you would be fighting against the sprung tension of the chain. The plunger goes back out to tension the chain as soon as you release the screwdriver.

Offline FireBladerDk

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Re: Valve Clearances
« Reply #5 on: 13 November, 2009, 09:17:27 PM »
Hi Syn,

you definitely don't need the cam chain tensioner locking tool if you only want to inspect valve clearances. I know this for a fact, because  I have done this inspection on my own CBF1000A and written the DIY article that Andy mentioned in his post.
It is only if you need to adjust the clearances it will come in as a handy tool, and even then it can be done with a screwdriver as badapple says. I have not tried this myself though.
You can read more about this here: https://www.cbf1000.com/index.php/topic,6571.msg86512#msg86512

Apart from saving money by doing this inspection yourself, there is another great benefit: you will be sure that all the spark plug cables have been handled gently, so your bike will not suffer from "post-inspection ignition cutouts" due to broken connections. So take your time and work carefully when fiddling around with these wires.

Cheers and enjoy ... Fred  :041:


Offline badapple

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Re: Valve Clearances
« Reply #6 on: 13 November, 2009, 09:29:58 PM »
Excellent artical FireBladerDK    :028:  :028:  :028:

Offline syn

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Re: Valve Clearances
« Reply #7 on: 13 November, 2009, 09:57:12 PM »
*Originally Posted by badapple [+]
Excellent artical FireBladerDK    :028:  :028:  :028:
Agreed, very clear instructions, thanks Fred.

The Haynes manual says:
*Originally Posted by Haynes
This procedure ensures that the valve clearances are measured with the oil clearance between the camshafts and their holders taken up

I don't fully understand that statement though and everybody who I've spoken to has said don't mess with the adjuster unless you want to remove the cams, including two guys I know and respect from my local Honda dealer.
One on the road's worth two in the shed... and hedge for that matter.

Offline FireBladerDk

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Re: Valve Clearances
« Reply #8 on: 13 November, 2009, 11:45:22 PM »
The cam shafts are layered in strong bearings on the cylinder head which hold the shafts firmly into position in order to keep the valve clearances precisely where they need to be. The tension of the cam shaft chain being tight or loose will hence not have any significant influence on the measured valve clearance values. Hence you may measure with or without doing anything to the chain tensioner.
As for the sentence you quote from Haynes, I can't find any meaning with it either. It sounds as they want to complicate something which is simple.

Cheers ... Fred  :041:

Offline syn

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Re: Valve Clearances
« Reply #9 on: 14 November, 2009, 11:41:56 AM »
*Originally Posted by FireBladerDk [+]
As for the sentence you quote from Haynes, I can't find any meaning with it either. It sounds as they want to complicate something which is simple.

I suspect it's been translated from Japanese, badly, so I put it through babel fish from English to Jap' and back:

*Originally Posted by BabelFish
This procedure rearrangement of the oil between the camshaft and the holder where rearrangement of the valve is taken guarantees the fact that it is measured

Simples  :001:
One on the road's worth two in the shed... and hedge for that matter.