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Offline raYzerman

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Valve Shim inquiry
« on: 26 August, 2019, 07:48:44 PM »
I am doing some forward planning for checking and swapping out valve shims.  I would like to purchase a range of shims I might need, I buy individual ones very reasonably.  I have a collection for my FJR which takes 9.48 diameter.  Seeking info from the knowledgeable collective..... are the shims typical Honda 7.48 OD or 9.48?  For those that have changed or measured shims, what is the approximate range in thickness either etched on the shim or measured?
Thanks in advance.

Offline oldtimer03

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Re: Valve Shim inquiry
« Reply #1 on: 27 August, 2019, 04:11:15 PM »
Apologies for sort of highjacking your valve shim thread, but I thought others might be interested to know the results of my recent valve clearance check on my Mk1 with 25000 miles on the clock. The inlet (I) tolerance is from 13-19, and exhaust (E) is 29-35 (hundredths of a millimeter). Results were;-
I1L=19; I1R=18; I2L= 17; I2R=17; I3L=18; I3R=17; I4L=18; I4R=17;
E1L=35; E1R=35; E2L=35; E2R=33; E3L=34; E3R=34; E4L=31; E4R=31
Clearly none needed to be adjusted, but the two tightest gaps on cylinder #4 will probably need re-shimming at the next (50000mile) interval.
This confirms to me what most on this forum have said, namely that leaving valve clearance checks to 25-30000 miles is okay. Hope this gives confidence to others who had doubts like myself. Happy days.

Offline raYzerman

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Re: Valve Shim inquiry
« Reply #2 on: 27 August, 2019, 04:59:12 PM »
Very good.  Always glad to hear what others have found.  My other bike experiences with bucket and shim (I've done a bunch of FJR valve checks too), the valve clearances get smaller as the valve head seats a teeny bit deeper, takes a very long time.  Even at minimum clearance, you still have plenty of clearance not to worry much, the danger zone is say 0.001" clearance or zero clearance.  But the bike performs better with the specified range.
One thing I do now, on that first valve check, I just adjust all the clearances to ~70% of max and so they are all the same (or as near as possible depending on shim selection).  Next check may never be needed, and the bike runs better, i.e., all cylinders balanced... I also do a TB sync, and I know the CBF has an "auto balance" system of sorts, but I will attempt a sync anyway as a good baseline.  I am hoping to minimize some of the buzzing that starts anywhere after 3500 rpm.  Worth a shot to me.  My FJR never ran better, so I'm OK getting all anal about it.  Hope the same idea works on the Biffer!
If no one knows the shim diameter and thickness ranges, I'll just postpone the check until winter when the bike can have downtime, I'll then get the shims I need and Bob's your uncle!
« Last Edit: 27 August, 2019, 05:00:55 PM by raYzerman »


Offline raYzerman

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Re: Valve Shim inquiry
« Reply #4 on: 27 August, 2019, 08:05:08 PM »
Thank you, Shed.  I know where I can borrow a Honda shim kit... 7.48 dia.
As for that ground connection, yes I use carbon based contact paste instead of dielectric for that kind of thing.
All looks pretty straightforward to me, but I'm no stranger to valve checks and shim changes.
thanks again!!

Offline Shed

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Re: Valve Shim inquiry
« Reply #5 on: 27 August, 2019, 08:10:43 PM »
Good luck with it, let us know how you get on when the time comes  :028:

Offline RJTaylor1000

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Re: Valve Shim inquiry
« Reply #6 on: 29 May, 2020, 03:50:08 PM »
I have been quoted £600 from a local Honda dealer for a 16,000 mile service as the valve clearances are covered. I nearly s**t myself! The engine runs quite and smooth and I can tell has full performance. I was very glad to read this isn’t really necessary until 30,000 miles. I will learn to do this myself by that time or won’t have the bike by then anyway. This seems a rip to me. I have done valve clearances on many types of OHC car using shims. Was easy once you have access. Is there a lot to strip out to get to the cams? Thanks for any comments or guidance. JT

Offline Art

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Re: Valve Shim inquiry
« Reply #7 on: 29 May, 2020, 04:26:07 PM »
That £600.00 for a 16,000 mile service only covers the inspection of the valve clearances, if any clearances need adjusting that's extra and I've heard folk tell of being bent over for £900 and then some. So long as you're not one of those that shouldn't be allowed spanners its an easy enough job for the home mechanic, a DOHC engine is a DOHC engine whatever the vehicle its fitted in and the CBF is no exception, if you've done one another is just another and much of a muchness.

There's good insight into valve clearances inspection here and the valve clearances adjustment here and if you haven't already you can download the Honda Workshop and Owners Manuals here




Offline Steelworker

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Re: Valve Shim inquiry
« Reply #8 on: 31 May, 2020, 04:15:48 PM »
I checked my valves recently as part of a "Covid 19 lockdown megaservice", CBF 2009 mk.1 at 32,000 miles.
All OK though all the exhaust valves closing up a bit at .29 - .30 which is not unusual for exhaust but no need to replace yet.
Probably got another 20 - 25,000 miles to go.
It's all a fairly straightforward job and the technical article links help a lot. It's also useful to have the tool kit supplied spark plug tool.
I rode Kawasaki fours for years and valve access was a lot easier but as Art says, DOHC engines are much the same so if your still mulling it over, just give it a go.
Just wish now I had somewhere to go, hopefully some bike rallies may be on later in the year.

Offline Art

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Re: Valve Shim inquiry
« Reply #9 on: 31 May, 2020, 04:26:26 PM »
Bike Rallies. Yes please, bring on the bike rallies. I did the 59th Dragon last February and I think I'd like to do one or two more in less extreme conditions.