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Timing / camshaft alignment on 2003 CB

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stormbringer
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Re: Timing / camshaft alignment on 2003 CB

Post by stormbringer on Tue 10 Mar 2015, 9:37 am

@Flyingbrick wrote:This is an extract from the Workshop Manual:



The limits included in the Haynes Manual are wrong, indeed. I just checked my own copy and you're right, they are talking about 0.02 mm in total, not +/- 0.02 as it's meant to be.
If the Haynes manual is wrong about this, someone within their organization deserves a spanking. And may I suggest this information gets triple verified and subsequently made into a 'sticky' in the right place on here.

Personally, I decided to hand this matter over to my local Honda-professional. You have to choose your battles, and I simply couldn't be bothered with this one. I'm quite sure I can do it, but as I'm relying on the bike for everyday transportation the fix has to be quick and correct.

Maybe next time.
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Flyingbrick
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Re: Timing / camshaft alignment on 2003 CB

Post by Flyingbrick on Tue 10 Mar 2015, 10:39 am

Just to make it clear: Haynes talks about 0.16-0.18 and 0.25-0.27.
But remember that the perfect clearance is 0.16 and 0.25, not 0.17 and 0.26. It is unlikely that there is no limit below the standard value.

I've cross-checked the specifications with the English and German Workshop manual as well as with the Swiss Bucheli book. Every source apart from the Haynes book specifies the limit to be +/- 0.02 mm.

This is the "Bucheli" extract:

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eternally_troubled
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Re: Timing / camshaft alignment on 2003 CB

Post by eternally_troubled on Tue 10 Mar 2015, 1:22 pm

I think this was intentional:  0.16 - 0.18 (and 0.25 - 0.27) is the 'looser' part of the Honda tolerance - I think this was done to ensure that people following Haynes set their valve clearances towards the 'looser' end of the tolerance.

Anyway, all this shows is that you can set it in quite wide range (0.14 - 0.18, 0.23 - 0.27) and still be OK.

EDIT: if you are doing this work yourself then I can't see any reason that you wouldn't aim for the 'looser' part of the range, thus increasing the mileage between shim-changes (assuming that your valve seats are slowly eroding and closing the valve clearances).
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Flyingbrick
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Re: Timing / camshaft alignment on 2003 CB

Post by Flyingbrick on Tue 10 Mar 2015, 1:48 pm

Well, I don't think that they had any intention. It is likely that they just made a mistake when they added 0.02 to the desired clearance and forgot that the difference has to be 0.02 mm more or less. Haynes does not define the values, they just put Hondas values into a plain advice for novices.

Anyway, if you choose one of the two sufficient shims, you can't go wrong.

sullivj
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Re: Timing / camshaft alignment on 2003 CB

Post by sullivj on Tue 10 Mar 2015, 5:20 pm

There's another error in Haynes, where it says to rotate 180 degrees anti clockwise, when they actually mean clockwise!
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HomeBrew
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Re: Timing / camshaft alignment on 2003 CB

Post by HomeBrew on Tue 10 Mar 2015, 6:36 pm

I would aim for the middle- 0.16 and 0.25 mm. Honda says that is the target value and it gives you the biggest room for error. Honda Workshop manual over Haynes manual.
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Flyingbrick
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Re: Timing / camshaft alignment on 2003 CB

Post by Flyingbrick on Tue 10 Mar 2015, 7:01 pm

Nevertheless, the Haynes manual is very good and much better than the Bucheli. It is quite expensive to get one in Germany, but it is worth the price.

By the way: I collect everything around the CB, including the books, brochures, pins and so on.
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georgecb500
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Re: Timing / camshaft alignment on 2003 CB

Post by georgecb500 on Tue 10 Mar 2015, 9:35 pm

I've aimed for the Honda nominal value, and managed to get pretty close so I'm happy with that.

Thanks to everyone for the help with this.  Hopefully it all goes back together ok and I can get on with something new!

Going to get the shims ordered tomorrow and hopefully they arrive before Saturday!
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georgecb500
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Re: Timing / camshaft alignment on 2003 CB

Post by georgecb500 on Tue 24 Mar 2015, 8:12 pm

Finally got round to finishing this job on Sunday. Or so I thought!

Everything went back together no problem, but when I remeasured the clearances one of them was out and two others were right on the upper limit.  Now I was absolutely meticulous with not mixing parts up so I'm certain the 'right' shims went in the 'right' place.  My maths was correct too. I torqued all the holders down correctly but I'm measuring a clearance larger than I expected.

I have thought I could take the can holders off and on again to see if the situation changes.  Anybody else had an experimental like this?

sullivj
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Re: Timing / camshaft alignment on 2003 CB

Post by sullivj on Tue 24 Mar 2015, 9:23 pm

I take it you're certain that the 'IN' and 'EX' marks are perfectly lined up?

Is there any chance you've got the chain one cog further than it was?

I presume you've not mixed up or rotated the covers?

Does seem a little odd......
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georgecb500
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Re: Timing / camshaft alignment on 2003 CB

Post by georgecb500 on Tue 24 Mar 2015, 9:55 pm

I'm pretty sure the cams were in the right position for measuring.  The two that are at the upper limit are inlet on cyl 1. The one which is out is far right exh on cyl2. So unlikely I would position it incorrectly both times.  The marks all lined up exactly as when I started.  I experimented with setting one tooth either way just to be sure as well. 

The holders definitely went back on correctly had them all marked up and kept in separate bags etc.

I rotated the engine a couple of times to settle everything in place as well.  I guess I'll just have to check again to be 110% sure.  The feeler gauges I have aren't brilliant so maybe taking some more precise baseline measurements would have helped.

sullivj
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Re: Timing / camshaft alignment on 2003 CB

Post by sullivj on Tue 24 Mar 2015, 10:13 pm

Sounds like you've done it all right George.

One other thought, did you measure the new shims that went in, to make sure they were what they said they were?
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eternally_troubled
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Re: Timing / camshaft alignment on 2003 CB

Post by eternally_troubled on Wed 25 Mar 2015, 1:06 pm

As sullivj mentioned, to be really sure you need to measure the shims that you are putting back in with a good micrometer - they are not always the size they claim!

Anyway, if you are within the tolerance I wouldn't worry. In fact, if your clearance is a tiny bit larger than the spec I don't suspect it would matter much (you should be more concerned if any of them are over the lower end of the limit).


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