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Vibration @ 6500 rpm VFR 800 fi


mog

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I’m new to the 5th gen VFR’s, so not sure if this is a fault or feature. The bike gets vibey from 6500 rpm in all gears, it’s initially noticeable through the left foot peg and doesn’t improve as the revs increase. Up to 6500rpm totally smooth. 
 

99 model. Low 10k miles as stored for 5 years by previous owner, although it was serviced during this time and run up to temperature. Recent oil and filter change. The valves have not been checked/ adjusted. I’ve not changed the spark plugs, as bike starts first time and idles/ runs smoothly up to 6500 rpm.


Any thoughts ?

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Even though an 90º V4 sports perfect primary and second balances they
still vibrate to some degree and the one thing to eliminate if you
feel more vibrations is a loose exhaust system because it will amplify
any of those vibrations to an annoying level... tap the pipes with the
palm of your hand to test if any bolts points or connections are
loose... also check the foot pegs bolts and anything bolted to the
foot pegs...

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Make sure you balance the starter valves correctly, it will vibrate much less when they are sync’d correctly. The difference is night & day. But there will always be a little vibration. 

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Thanks for the pointers, I didn’t realise the starter valves needed balancing on the 99 models with choke cable.

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Checked the exhaust, no movement, so that’s another thing eliminated. Same with foot pegs, no unusual movement. I’m loathed to get the valve clearances checked as the engine sounds quiet for a VFR and fuelling is spot on. For an early fuel injection system it’s just about perfect. Has anyone cured the 6500 rpm + vibration by getting the valves adjusted?

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When you get a good deal on a bike that was stored away in the back of a garage for years you have to suspect that there was a reason the bike got relegated to the dark shadows.

 

Now it could be that there's a simple, harmless (not mechanical) reason for the bike getting stored, something like the owner having a near-death experience that scared him so badly he quit riding.  But more often than not the case is something mechanical related was making the bike disagreeable, worrying or just not fun to ride any more.  People put bikes like that in the back of the garage and ignore them.

 

When you take possession of a bike with this sort of history (i.e., mostly unknown, long stored or highly suspect) you should be willing to give it a good bit of precautionary/refurbishment maintenance.  You just have to accept that this "good-deal" bike might require some investment of money, time and effort.

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Good point. However it’s got a full stamped history before being stored in his garage and I have no reason to believe the owner didn’t keep it serviced during this time. The bike was owned by an automotive engineer who had access to several bikes, he was keeping the Anniversary edition VFR as an investment but prices of VFR’s in the UK haven’t really seen much of an increase over the years.
For me it’s a keeper, I’ve been after an Anniversary model for quite a few years.
 

Precautionary maintenance well under way. New brake fluid, clutch fluid, oil changed, coolant changed and recent tyres. There’s a receipt for spark plugs and air filter changed, but this was 5k miles ago, so worth a check. Next on the list starter valve synchronisation as recommended by Mohawk.

 

 

 

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1 hour ago, mog said:

Checked the exhaust, no movement, so that’s another thing eliminated. Same with foot pegs, no unusual movement. I’m loathed to get the valve clearances checked as the engine sounds quiet for a VFR and fuelling is spot on. For an early fuel injection system it’s just about perfect. Has anyone cured the 6500 rpm + vibration by getting the valves adjusted?

You still have a ways to the 16,000 mi valve adjustment interval.  For reference recently  I was doing other work on my 5G motor that has a bit less time on it than yours and decided to have a look at the valves.  They weren't perfect, but well within range.  You can't draw any conclusions about valve clearances by how it sounds as they'll tighten up over time.  If they get so tight that they cannot seat properly then you probably would have some rough running issues.  On a 10,000 mi motor that's highly unlikely. Rough running can have many causes,  including clogged injectors, mis-fire, intake leaks and other issues.  The former is very possible given the age and that it's been sitting so long. Poor fuel delivery can cause uneven output amongst the cylinders. You mentioned the 6500 rpm mark "in all gears".  Is that present in neutral?   I'm wondering if the chain might be too tight. 

Diagnosing is a process of elimination taking nothing for granted.  Check or test the easy things 1st - wiring,  ignition

(including plugs and leads),  induction (airbox, filter) then the fuel system until you find the issue(s).  

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I didn't get the impression the OP thought it was running rough. Just a bit vibey which is similar to my 98. I too will do the starter valves at some point but my engine has less than 4000 miles on it (a garage queen for over 20 years) so it isn't going to be related to valve clearances. I assumed it was normal.

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My 2000 VFR  would idle fine but would "chuff"  or miss under low rpm load.  It was weird when it would miss. 3000-4000 rpm under load.  But it would rev to redline.   I found the plug wires all have a 5K ohm resistor in the top of the plug cap.  (The resistor is there to help reduce radio interference.)  It has metal caps and I could not get them clean enough to pass an ohm meter test.  I had 2 bad plug wire resistor contacts.  I have an ohmmeter so I could do a continuity check from the tip that grabs the plug electrode and remove the plug wire from the coil, then stick the other ohmmeter probe into the end of plug wire.   The meter should read ~5000 ohms. It should not read OPEN!    So Ohm all 4 wires and caps.  IF some are open, change them.

So to make resistor plug wires, Honda used copper wire High Voltage cables, and then hid a resistor in the cap.   You can buy new plug caps with the resistor.  You may have just 1 open resistor, causing an imbalance in power pulses.   Now since I had 2 resistor contact failures out of 4, I went and installed resistance wire (they have a carbon center conductor and found a plug cap that would fit and seal the top.  So I eliminated the resistor.  Most automotive plug wires are the resistance style and many say it.   But most sane people would just go buy new plug caps from Honda and be done with it. 

 

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Thanks for your suggestions. Agree, plugs, leads and air filter are any easy check. Whilst in storage the bike was on an optimate charger and had a petrol additive added to the tank to help prevent the fuel gumming up, the oil was changed at the same time as his other bikes and regularly started up. As Jeremyr62 noted; my bike is super smooth all the way to 6500rpm, starts on the button and idles smoothly from cold. My last bike was a 2010 1250 bandit in-line 4, no vibes across the rev range, brilliant do it all bike, but I still rate my older VFR as a better all round package. Handling is far superior, it out brakes the Suzuki, looks fantastic, has v4 character and sounds lovely. 

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Well, good luck with the bike.  Hoping your various maintenance actions will make the odd feeling go away.  Sometimes people "solve" problems without ever knowing what the problem was.

 

Having what feels like a cylinder "dropping out" as RPMs climb is a pretty worrying feeling.   Based on the VFR800 engine firing order the cylinders that I believe would cause the biggest "feel" if one of them started dropping out would be either #3 or #2 because...

 

... VFR800 firing order (in 90 degree increments): 1-0-3-0-0-2-0-4-

 

so if either #3 or #2 dropped out you'd get a really long (450 degree) empty space.  And the #2 cylinder might be the worst of the two because it dropping would place the 450 degree empty space just before the (signature VFR800 V4 item) cylinder #4 and #1 big-bang combo (only separated by 90 degrees). 

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