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Now I've had my new-to-me 2000 for two months.  As with any used bike purchased, one always wishes for more information about its past life and what's been done, but that's just life.

I've put on about 1500 miles so far and the bike has been a mixed bag.

It arrived with 30K miles and in very good overall condition.  I like to look for tells on what level of attention a bike's gotten, and this one sports Galfer stainless brake lines.  That's always a good sign to me, one of the better ones.

My take is that the previous owner rode it some but less in recent times.  It starts perfectly and idles well, albeit right at the high side of spec and can't be adjusted any lower.

The throttle response is good all across the range, although I'd rather have less snatch in the first portion of the range, like pretty much everyone else.

So far I have two main problems with the bike, the first being the ergos, specifically the bars.  They are simply too low and far forward for me.  I'm not as flexible as I once was and have an old neck problem that hasn't allowed me to use lower bars since the mid-'80s.  I've installed longer throttle cables, rerouted the brake and clutch lines, pulled out more length on the handlebar switch leads, and am experimenting with higher bars.

But the bigger bug is the vibration.  I'd been told many a time how smooth the VFR engine is, but this isn't the one.  Now, I'm no sissy- I put 50K on a BSA twin once upon a time- but the hands are taking more of a beating on longer highway stretches than I care to take.  Specifically, at 70+mph, it's enough to bring discomfort.

On a conventional four-cylinder, such as the ZX-9R I sold to buy the VFR, one starts with a valve adjustment and a carb/throttle body synchronization.  On this bike, the valves ought to be near enough to spec since they were supposedly done at about 17k and are only coming due now, and I am not seeing a TBI sync procedure in the factory manual.

I have some ideas, but I would look to the conventional wisdom first to decide on a path.  GIven that there's a half-dozen other bikes in the garage, there's only so much wrenching time to be had.

For heaven's sake, the Missus has just informed me she's interested in a GSX-R600 front end graft on her SV650S.  If that isn't an inhaler of time, I don't know what would be (besides a BSA crank bearing upgrade job).

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Welcome...

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 or hear an odd rattle 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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The procedure you are looking for is "starter valve sync," but this really only comes into play at cold idle.  It's not difficult, and pretty closely related procedurally to a carb vacuum sync which it sounds like you know.

 

But if your VFR is vibrating more than your inlines, there is almost certainly more to it.  If it's not something like loose parts or whatnot, I'd start with something easy like dumping Redline SI-1 fuel injector cleaner or something else with lots of PEA in the tank and seeing if it gets better.  If it does, then it might be injectors.  Spark plugs, ignition coils, etc. also come to mind but those may throw FI indications.

 

My bike is 19 years old and the "in between owners" I repurchased it from let it sit outside.  A lot.  So injector fouling is one of several things I am working through.  It doesn't cause bad vibes and the bike runs smooth on the gas, but I can imagine if it was worse.  

 

You mention at 70+ though,  Is it speed related, or RPM related?  At the handlebars, seat, or pegs?  If it's speed, then other stuff could be fork internals, sprockets, chain condition, swing arm pivot, dogbone link, rear shock, etc.  

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One other thing...normal is completely smooth at the handlebars.  You know how on most bikes you can tell where the natural damped frequency of the bars are and try to keep the RPM's above or below it on long stretches, or install bar snake and weights to try to push the frequency down?  Yeah there's none of that on a VFR.  Should be smooth or something is up!

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One other thought...If it's rpms that are the issue cruising along at 70 mph, you could change the gearing a little to bring the rpms down at higher speeds.

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12 hours ago, TimC said:

One other thought...If it's rpms that are the issue cruising along at 70 mph, you could change the gearing a little to bring the rpms down at higher speeds.

 

A thought re your thought: the OP should ascertain whether the bike's current sprockets are in OEM sizes--people sometimes gear down with aftermarket sprockes, which raises the RPM used in "normal riding".

 

Ciao,

 

JZH 

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I had a similar problem. Turned out to be a majorly-imbalanced from tire. Installed new tires. Gtg. If there are binding links in your chain you will also feel vibrations. If your chain is loose in some spots and tight in others that's probably causing the vibrations.

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6 hours ago, JZH said:

 

A thought re your thought: the OP should ascertain whether the bike's current sprockets are in OEM sizes--people sometimes gear down with aftermarket sprockes, which raises the RPM used in "normal riding".

 

Ciao,

 

JZH 

All good points, but I think if the vibes are RPM-correlated and increase monotonically (only go up as RPM goes up), and significantly worse than an inline four...something is wrong like a clogged fuel injector that's causing an irregular engine imbalance.    

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7 hours ago, JimMoore said:

  If your chain is loose in some spots and tight in others that's probably causing the vibrations.

 

usually means chain is worn out, needs replacement.

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Some bad info supplied here re starter valve sync. Thats just Hondas name for throttle bodies sync & it works through the whole rev range. Out of balance TB's cause vibration & hesitancy in acceleration. When done properly the engine will rev immediately & rapidly with no vibration or hesitation. 
 

Vibration at a set speed can be caused by many things. You should check the rpm this is happening at the use a lower gear at same rpm, whatever speed that may be. If vibration is the same it may be engine related. If different then its likely to be cycle part related. As previously mentioned tyres, chain or sprocket wear etc. 
 

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I also chased vibration that I would have sworn was coming from the engine.  After a tire shop added 4oz to a new Michelin, I built a simple balancer and started balancing my own tires.  The vibration is gone and has never come back.  Just one possibility.

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Having looked through all the replies, I have a bit more perspective to add.

I'm approaching 2000 miles covered with the bike so far.  The vibration, again primarily in the bars but also in the pegs, is RPM-related.  It becomes noticeable right around 5000 RPM and increases with engine speed.

To hit some of the points above, the tires on it were good but old.  I had Pirelli Angel GT2s installed at the local shop where the tech is not only very experienced but a VFR fan.
The tire change made no difference in the vibration level.

The chain appears good, is within stretch service limits, and is not showing kinks.  The countershaft area was well-splattered with old and new chain lube, suggesting there had been maintenance.

I remounted the Heli Multi-Tour Sport handlebars on different adapter risers and it did lessen the vibes a little.   I have medium-weight Throttlemeister bar ends installed.  Past experience with this Heli bar on other bikes shows they usually reduced grip vibration over stock, so I don't think there's a problem there.

It does appear I will need to get after the starter valve synchronization.

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Aha, if you have higher replacement bars. Try adjusting the weight. Take the existing weights off & see if its better or worse. That will give you an idea if you need more or less weight. 
 

But its likely to be weight related. The VFR does have a roughish vibration in the 5-7k range, but its barely noticable with the standard bars & weights. 
 

Keep us posted. 

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I used to have helibars...no significant change in vibration with them.  My blind internet guess is stiIl starter valves, but try some high PEA fuel injector cleaner too like Redline SI-1.  Also, spark plugs...

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