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bad, bad, bad.....bad vibraaaations !!!!
Posted: Tue Jan 22, 2002 12:54 am
by bitsurfer001
Ok, its time to call on the collective for this one.
This is a motor vibration, unmistakably.
The motor cycles through a steadily increasing, peaking then
decreasing vibration. I would say it cycles every 5 seconds or so.
The bike will ride down the road, completely normal. Then, I start to
feel the vibration as the turn signals begin to shake, the amplitude
of the vibration increases until the whole bike is "a-buzz" and it
feels like the cylinder tube and head are going to fly off the bike.
The vibration will then subside as the same rate it came on. It will
run perfect for the next 5 seconds then the cycle starts again.
Pulling in the clutch does not effect the vibration.
{don't try this next part at home}
This happened 50 miles after I had the head off the bike and put it
back together. My cam chain timing was off about 3 teeth when I
initially installed the cams. Before I noticed I did turn the motor
over by hand past the point of no return, which is when I realized
the cam timing was off. I thought the resistance was due to the cams
pushing on the valves, but no, it must have been the valves hitting
the piston.
So, lets say I have bent valves. The bike did run great for 50 miles,
so I am wondering if it is something else. Would bent valves be the
cause of the cyclical vibration ? Also, what if the motor was not
quite at TDC when I timed the cams the second time ??? I made sure
the head bolts were tight.
Pete
88 KLR
90 Tengai
bad, bad, bad.....bad vibraaaations !!!!
Posted: Tue Jan 22, 2002 2:45 am
by RM
On Tue, 22 Jan 2002, bitsurfer001 wrote:
>The motor cycles through a steadily increasing, peaking then decreasing
>vibration. I would say it cycles every 5 seconds or so. The bike will
>ride down the road, completely normal. Then, I start to feel the
>vibration as the turn signals begin to shake, the amplitude of the
>vibration increases until the whole bike is "a-buzz" and it feels like
>the cylinder tube and head are going to fly off the bike. The vibration
>will then subside as the same rate it came on. It will run perfect for
>the next 5 seconds then the cycle starts again.
This suggests that you have two sources of vibaration that are not
perfectly in sync with each other. The vibration effects are additive
when in-phase and five seconds later they cancel each other when out of
phase.
Did you disassemble anything at all having to do with the counterbalancer
system? Remove the chain?
bad, bad, bad.....bad vibraaaations !!!!
Posted: Tue Jan 22, 2002 7:49 am
by Ted Palmer
bitsurfer001 wrote:
[...]
> So, lets say I have bent valves. The bike did run great for 50 miles,
> so I am wondering if it is something else. Would bent valves be the
> cause of the cyclical vibration ?
I doubt it.
> Also, what if the motor was not
> quite at TDC when I timed the cams the second time ???
Then it probably would not run great at all.
Like RM suggests, I suspect the counterbalancer system is out of sync.
Mister_T
Melbourne Australia
bad, bad, bad.....bad vibraaaations !!!!
Posted: Tue Jan 22, 2002 8:22 am
by Bogdan Swider
> the amplitude
> of the vibration increases until the whole bike is "a-buzz" and it
> feels like the cylinder tube and head are going to fly off the bike.
>
Having had the experience of ridding 1000 + miles with my balancer system
out of sync it seems to me you have a version of the same malady. You did
the same with the valves so it seems you're at least consistent. You'll have
to remove the magneto and take a look. The instructions in the manual are
fairly clear. Also I can forward you some info that will further help you
set the timing.
Bogdan
bad, bad, bad.....bad vibraaaations !!!!
Posted: Tue Jan 22, 2002 10:46 am
by Ryan Newman
> This is a motor vibration, unmistakably.
> The motor cycles through a steadily increasing, peaking then
> decreasing vibration. I would say it cycles every 5 seconds or so.
> The bike will ride down the road, completely normal. Then, I start to
> feel the vibration as the turn signals begin to shake, the amplitude
> of the vibration increases until the whole bike is "a-buzz" and it
> feels like the cylinder tube and head are going to fly off the bike.
> The vibration will then subside as the same rate it came on. It will
> run perfect for the next 5 seconds then the cycle starts again.
> Pulling in the clutch does not effect the vibration.
Ok, so if you pull in the clutch at speed, and the engine goes down to idle,
there is NO difference? If that's indeed the case, then I would suspect that
the problem isn't with the engine at all. If you had bent valves, the bike
wouldn't hardly even run, so that's not your problem.
Ryan
Phoenix
bad, bad, bad.....bad vibraaaations !!!!
Posted: Tue Jan 22, 2002 11:39 am
by Mark
At 9:40 AM -0700 1/22/02, Ryan Newman wrote:
> > This is a motor vibration, unmistakably.
> > The motor cycles through a steadily increasing, peaking then
> > decreasing vibration. I would say it cycles every 5 seconds or so.
> > The bike will ride down the road, completely normal. Then, I start to
> > feel the vibration as the turn signals begin to shake, the amplitude
> > of the vibration increases until the whole bike is "a-buzz" and it
> > feels like the cylinder tube and head are going to fly off the bike.
> > The vibration will then subside as the same rate it came on. It will
> > run perfect for the next 5 seconds then the cycle starts again.
> > Pulling in the clutch does not effect the vibration.
>
>Ok, so if you pull in the clutch at speed, and the engine goes down to idle,
>there is NO difference? If that's indeed the case, then I would suspect that
>the problem isn't with the engine at all.
Ya, if that's the case, I would lean towards a severe wheel balance problem.
Does it only happen when you're rolling?
Have you tested this with the engine at 4000RPM with the bike stationary?
Mark
B2
A2
A3
bad, bad, bad.....bad vibraaaations !!!!
Posted: Tue Jan 22, 2002 1:26 pm
by ephilride@aol.com
At 9:40 AM -0700 1/22/02, Ryan Newman wrote:
> > This is a motor vibration, unmistakably.
> > The motor cycles through a steadily increasing, peaking then
> > decreasing vibration. I would say it cycles every 5 seconds or so.
> > The bike will ride down the road, completely normal. Then, I start to
> > feel the vibration as the turn signals begin to shake, the amplitude
> > of the vibration increases until the whole bike is "a-buzz" and it
> > feels like the cylinder tube and head are going to fly off the bike.
> > The vibration will then subside as the same rate it came on. It will
> > run perfect for the next 5 seconds then the cycle starts again.
> > Pulling in the clutch does not effect the vibration.
>
>Ok, so if you pull in the clutch at speed, and the engine goes down to idle,
>there is NO difference? If that's indeed the case, then I would suspect that
>the problem isn't with the engine at all.
Do the basics first. Tighten all bolts, starting with the engine mounts. --
knot