05 Mar 24, 06:59 am

Recent Posts

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21
General Maintenance, Servicing, and Mechanical / Re: Rear Sprocket nut torque
« Last post by raYzerman on 19 February, 2024, 10:41:53 pm »
In my opinion, this is a classic case of over-engineering.  The studs are heftier than most other similarly powered bikes' sprocket bolts.  Their torques are much lower, so I propose you go 108NM max with a dry thread.  In addition, the nuts are FujiLoc (as is the rear axle nut), with the metal piece that indeed is your thread locker.  They won't come loose.  Nor is there really any significant side load on the sprocket.

As for lubricated threads, consider Loctite a lubricant if you used a liquid.  When anti-seize or "copper grease" is used, the torque should be reduced 30% and you will achieve the same clamp load.  If you lubed with engine oil, you'd reduce it even further. 

I'm just swapping out my rear sprocket today to change the gearing... I'm going to use a common sense torque of ~80Nm.  A short list of a few bikes and their torques......

VFR800 - 34Nm (25 ft. lbs.), surprisingly low one could say
Versys 1000 - 60 (44)
Tracer GT - 80 (59)
DL1050 - 60 (44)
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General Maintenance, Servicing, and Mechanical / Re: Rear Sprocket nut torque
« Last post by YDraig on 19 February, 2024, 11:41:59 am »
Just for completeness if anyone else goes through this thread:
With clean and dry threads I stuck with the 108NM torque setting, there were no signs of any issues going this tight.  Thing is I've known the manual (manufacturers workshop) be wrong before on other bikes (wrecked one kawasaki head with wrong cam-chain tension procedure from following the manual many years ago)...
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General Maintenance, Servicing, and Mechanical / Re: 16k Service - How important is it?
« Last post by Art on 18 February, 2024, 04:00:20 pm »
The sections on Throttle Bodies in the Honda Workshop Manuals will be of interest
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It is quite true all in-line fours have an inherent vibration, usually in the 4000-5000 rpm range.  To combat this, counter rotating balancers are used (e.g., two in the ST1300 and FJR1300, one in the Kawasaki 1000's and CBF1000).  There is a gear lash adjustment, however that is only for gear noise, not position of the balancer(s).  One would have to blueprint an engine to attempt to further reduce that physical vibration, but that would make engines cost prohibitive on a mass produced basis.

The only other way to reduce vibes is to tune the engine to have each cylinder breathing as close to the same as possible.  Valve opening heights and open time duration affect this, and valve clearances if all uniform will produce the best situation.  As I mentioned as an example, if one were to set one pair of cylinders at minimum clearances and one pair at max, this would be the worst situation.  It's only logical.  I've done many valve checks/reshimming on various bikes to have the clearances uniform and the results are definitely noticeable if they were badly off to start with.  It all depends on how bad (far apart) they were in the first place.  If most were hovering around nominal, then you'll not likely notice much if any benefit from tweaking them all to one particular number.  They are already "uniform enough".  Unfortunately, I have found some wide variances, usually at the first valve check.  Each one is different and a judgement call based on your initial findings.

You certainly don't have to do what I do.  Within tolerance is OK.  But if I have to pull cams, I'm going to do the best I can while I'm in there that deep.  Setting them somewhat above nominal will just buy a lot more time before one has to go in there again.

The other adjustment is on throttle body vacuum, usually each throttle body has a tapered air bleed adjustment screw.  It's standard procedure in all the service manuals to perform a throttle body sync.  This vacuum is affected by valve clearance uniformity for the most part.  On the CBF, given the first look, it appears Honda attempts to automatically balance by linking the TB's together with a common vacuum hose arrangement, but I have to investigate this further.  I have not dug into it to see if the TB's have adjuster screws, but I'd say there had to be a way for them to bench balance them during assembly.  I'm not due for a valve check/TBS yet, and will get into it next winter.
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General Maintenance, Servicing, and Mechanical / Re: 16k Service - How important is it?
« Last post by Art on 18 February, 2024, 11:39:03 am »
Engine vibrations are inherent to engine design and mostly caused by a combination of crankshaft configuration, ignition timing and firing order but are also due to imbalances of rotating and reciprocating parts such as pistons, con rods, flywheel etc.

If valve clearances are within the manufacturers specified tolerance, albeit at the minimum or maximum of that tolerance, they should not have any noticeable effect on engine vibration. However, if one or more of the valve clearances are outside the specified tolerance that can cause pinking (aka pre-ignition or engine knock). Pinking can appear as a slight engine vibration or a heavy engine knocking and in the extreme cases cause a violent rocking of the engine.

Of course, there can be many other causes of excessive engine vibration and the assumption here is that the engine is in good mechanical condition.
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I'd extend the interval too, not a problem on this bike.  As for the vibrations, if you want to test it, set two cylinders at minimum clearance the other two at max clearances.... that should tell you the tale.
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General Maintenance, Servicing, and Mechanical / Re: 16k Service - How important is it?
« Last post by Bluefox on 17 February, 2024, 05:39:00 pm »
I have a very good friend who is a senior technician at a Honda dealers, who told me not to even think about the valve clearances on my mk2 til at least 32k
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Your bike, your choice. I can tell you now though, hitting either end of the valve clearance with have less than zero effect on vibrations from the engine.
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Items Wanted / Re: Wanted - Givi TN460 or Kappa KN460 Crash bars for MkII
« Last post by raYzerman on 16 February, 2024, 02:08:08 pm »
Thanks for the advice, Art.  The situation these days is choices are limited for MkII.  One can find bars for MkI easily enough.

Additional tip, use anti-seize on the threads of your bolts to prevent the inevitable bi-metal corrosion with aluminum, but use a lubricated thread torque value, approx. 25% lower is good enough (most recommendations are 30-35%).
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The concept is to primarily get them all as uniform as possible for the smoothest performance.  You would decide on what/how many based on the current clearance measurement.  70% would be 0.33 and 0.17mm respectively.  You could pick a percentage on either side of that based on the situation, you may save re-shimming one or two but you're in there anyway.  I have a spreadsheet where I can play with the theoretical clearances and shim sizes, but again, I'll target being uniform and over nominal.

In my case, I have perhaps a more advantageous situation.  I use ProX shims, U$2 each and they come in .025 increments.  I've done many bikes and have a kit with a good selection collected over the years.  I have met people who actually sand shims to achieve perfection, but I can't be bothered.
 
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