Author Topic: 86 Suzuki GSX 750(?) problems.  (Read 2631 times)

Phyphor

  • friend
  • Senior Member
  • ***
  • Posts: 2,328
86 Suzuki GSX 750(?) problems.
« on: February 28, 2006, 08:49:24 PM »
Bought 'er used about 6 months back, learned the hard way how to work on the powertrain, now I gots other problem(s) with it...

This damned thing always did have a slight shimmy going above 70...well, said shimmy is now down around 40mph, and it seems to be getting worse.  Can't hear anything or really feel anything wrong, except it feels.......well, 'loose' in the front, and like I said, kinda shimmies.

Keep in mind, it's my first motorcycle, and I don't know much about it...any ideas?  Could it be tire wear?
"You know what's messed-up about taxes?
You don't even pay taxes. They take tax.
You get your check, money gone.
That ain't a payment, that's a jack." - Chris Rock "Bigger and Blacker"
He slapped his rifle. "This is one of the best arguments for peace there is. Nobody wants to shoot if somebody is going to shoot back. " Callaghen, Callaghen, Louis La'mour

Fatcat

  • New Member
  • Posts: 32
86 Suzuki GSX 750(?) problems.
« Reply #1 on: February 28, 2006, 10:27:27 PM »
It certainly could be the tires, how old are they? If they were on the bike before you got it, I would think about replacing them... you never know how long they sat, and old rubber is scary. Are they worn way down? Tire pressures ok?
"The greatest mistake you can make in life is to be continually fearing you will make one."

Guest

  • Guest
86 Suzuki GSX 750(?) problems.
« Reply #2 on: February 28, 2006, 11:20:50 PM »
I assume youve checked tire pressure and everything really obvious. A lot of things could cause a wobble like that; damaged wheel/tire, front axle bearings, bent forks, warped rotor, and probably a thousand others. My money says its probably the bearings, since it is getting progresively worse. Whatever it is it needs to be fixed before you ride it again, things like this can go from bad to really bad very quickly and you dont want to be riding it when that happens. I generally hate going to shops because its expensive, but for a problem like this it might be your best bet. Alternately you are really going to have to tear down the whole front end starting with the wheel and keep working your way back untill you find something amiss.

In completely coincidental bike related news I crashed my poor machine about 2 hours ago and snapped off the clutch lever, so im kinda bummed too. Let me share some motorcycle commiserations.

BillBlank

  • friend
  • Member
  • ***
  • Posts: 191
86 Suzuki GSX 750(?) problems.
« Reply #3 on: March 01, 2006, 12:09:25 AM »
Hi Phyphor, hmm, if you mean GSXR then that's an interesting first bike.  You have taste. The best advice I can give you is to get your bike in front of someone who knows what they're doing before you ride it again. Bearing failures at speed are invariably painful. Bearings are also not that expensive so it would be a shame to destroy a bike for the sake of a $50 part.

Buy the workshop manual for it, not the haynes manual (or american equivalent). It's full of really useful information that will ensure that your motorcycle is set up as the manufacturer intended. Sit down with a nice cup of cocoa in your garage away from distractions and inwardly digest.  

What C_yeager and fatcat said about tyre pressures, tyre wear and wheel bearings etc.  

In addition:

A few basic health checks.
(edited to add) HEALTH WARNING: WAGGLING A BIKE AROUND WHEN IT'S ON IT'S SIDESTAND CAN RESULT IN IT FALLING OVER. IF IN DOUBT HAVE SOMEONE THERE TO HOLD THE BIKE UPRIGHT AND TO BEAT UP IF THEY DROP IT Smiley

Steering head bearings.
What does the steering feel like at a standstill when you turn the bars from side to side? Are there any notchy or crunchy sensations?
Sit on the bike and with the front brake on push and pull at the bars. Does this result in a knocking sound or sensation through the bars?
Grasp the bottom of the fork legs firmly and push and pull at them
Wheel bearings.
With the bike on it's stand grasp the top of each wheel from the side and push and pull with care. If you can make the wheel move backwards and forwards towrds and away from you to any great degree then your wheel bearings are past their best.

Swingarm bushes and bearings.
Repeat the above procedure with the swingarm. What you're looking for is lateral movement or crunchy-knocking sensations where there shouldn't be any.

Engine mounts. Locate the bolts that attach the engine to the frame. You say you have rebuilt the transmission. If you removed the engine to do this without consulting the workshop manual then there is a strong possibility that you tightened the bolts to the incorrect torque setting. There may even be a specific order to tighten them in. In my experience with motorcycles where the engine is a stressed member failure to correctly refit the engine produces similar symptoms to what you describe. In my case I was test riding my current '02 750 to which the owner had fitted crash bungs that replaced the top two engine mount bolts. One was hand tight and the other was overtightened by 40% and was lucky not to have stripped the thread. Exiting corners and accelerating became interesting as the engine moved around.

Anyway, can't think of anything else off the top of my head, go get it looked at if you are at all unsure.

To c_yeager: Ah, my sympathies. Was it at least a "man's" accident? Not one of those dropping it in a car park at two miles an hour because I was looking at girls instead of where I was going ones? Smiley Tongue.
Just so happens Satan's behind the bar pulling the late shift for a buddy...

InfidelSerf

  • friend
  • Senior Member
  • ***
  • Posts: 884
86 Suzuki GSX 750(?) problems.
« Reply #4 on: March 01, 2006, 06:21:07 AM »
I'll second checking your tires and headbearings.
Based on the age its probably a good idea to just replace them both.
The hour is fast approaching,on which the Honor&Success of this army,and the safety of our bleeding Country depend.Remember~Soldiers,that you are Freemen,fighting for the blessings of Liberty-that slavery will be your portion,and that of your posterity,if you do not acquit yourselves like men.GW8/76

griz

  • friend
  • Senior Member
  • ***
  • Posts: 3,042
86 Suzuki GSX 750(?) problems.
« Reply #5 on: March 01, 2006, 01:58:19 PM »
Another vote for steering head bearings, Mr. Blank describes perfectly how to check them. As a matter of fact I will just say ditto to his advice.
Sent from a stone age computer via an ordinary keyboard.

Guest

  • Guest
86 Suzuki GSX 750(?) problems.
« Reply #6 on: March 01, 2006, 03:03:56 PM »
It just occured to me that you shouldnt completely discount the rear wheel as well. A rear tire that is out of alignment could cause symptoms that you describe. Its pretty easy to check the alignment, so I would do that before tearing anything else apart. You dont describe any weird vibrations coming through the bars, so that might be because the prolem is coming from somewhere else.

gunsmith

  • I forgot to get vaccinated!
  • friend
  • Senior Member
  • ***
  • Posts: 8,179
  • I'm sorry, Dave. I'm afraid I can't do that.
86 Suzuki GSX 750(?) problems.
« Reply #7 on: March 22, 2006, 11:02:32 PM »
Where in the peoples republic are you? if your in the Bay Area find O'hanlans motorcycle in SF, tell them a gun nut sent you, they will know its me.

I love those old suzuki's I hope you can fix it up...oh and spend the money for good safety gear, it's fun and even though it's expensive it really is worth it.
I allways wore those big thick moto cross boots that go way up to your knee, one time I was looking at some girls on polk and the guy in front of me stopped short for the sam reason and I dumped the bike on my leg, i was pinned under the bike.
if I hadn't had the good gear on I coulda been hurt ...instead I was just embarrassed
Politicians and bureaucrats are considered productive if they swarm the populace like a plague of locust, devouring all substance in their path and leaving a swath of destruction like a firestorm. The technical term is "bipartisanship".
Rocket Man: "The need for booster shots for the immunized has always been based on the science.  Political science, not medical science."

Guest

  • Guest
86 Suzuki GSX 750(?) problems.
« Reply #8 on: March 23, 2006, 07:44:57 AM »
Most likely it's either steering head bearings or swingarm bearings.

Lemme back up a sec: if this is your first bike, it's...not a great choice.  Watch out, OK?  It's twitchier than Sarah Brady at Knob Creek and has power for miles.  If you don't know what "countersteering" is stay the heck off until you do!

OK.  As to fixing it: assuming there's no centerstand, and I don't think there is, it'a pain to get each wheel one at a time off the ground unsupported and with nothing touching the suspension.  You only need to do one end at a time.  The front is easier: with the sidestand down it's possible to lean it up onto the sidestand and get the front tire off the ground...then somebody else can grab the front tire and wiggle it around in all directions.  Loose steering head bearings will be obvious.

Getting the rear similarly "up" is harder.  You need an overhead lift system of some sort.  Heavy duty winch straps and a good solid overhead beam in the garage may be enough.  Same deal: wiggle the rear tire around.

A loose rear can make the front feel loose, while a loose front can make the rear feel loose.  Don't depend on "feel while driving" to see which end is screwed up.  It could very well be both, on an older sportbike that's probably been flogged to heck and gone.

gunsmith

  • I forgot to get vaccinated!
  • friend
  • Senior Member
  • ***
  • Posts: 8,179
  • I'm sorry, Dave. I'm afraid I can't do that.
86 Suzuki GSX 750(?) problems.
« Reply #9 on: March 23, 2006, 10:03:02 AM »
I have to gentley, politely and very respectfully disagree with Jim on the subject of countersteering.
I'm not saying it doesn't work, I've seen it on tv during motorcycle races...but...imho, you don't need to master
that technique to ride safely.  ( Do they even teach it during the motorcycle safety course most folks take? )

I was a motorcycle messenger for years, in CA lane splitting is legal.  Not at the high speeds I did it, but legal.
I spent years and years going from SF to Sacramento to San Jose and points in between, at high speeds in lots of rain, and lane splitting, never once countersteering (unless of course, I just do it naturally, which is possible).

I've been in 8 to 10 accidents  all at very slow speeds  two involved looking at girls mini skirts and trying to drive real slow ( so I can look longer ) the rest  were all under 25 mph,4 involved braking on sand and gravel or loose small pieces of cardboard (all in SF) 2 were those darn cable car tracks in SF (turning  when wet over them is to be avoided) and a couple of losers making illegal left turns in front of me causin me to dump it.

So in my opinion if you can learn counter steering, more power to ya.   If you can't,  take the motorcycle safety course and don't sweat it.
Politicians and bureaucrats are considered productive if they swarm the populace like a plague of locust, devouring all substance in their path and leaving a swath of destruction like a firestorm. The technical term is "bipartisanship".
Rocket Man: "The need for booster shots for the immunized has always been based on the science.  Political science, not medical science."

Fatcat

  • New Member
  • Posts: 32
86 Suzuki GSX 750(?) problems.
« Reply #10 on: March 23, 2006, 12:37:07 PM »
Quote from: gunsmith
I have to gentley, politely and very respectfully disagree with Jim on the subject of countersteering.
I'm not saying it doesn't work, I've seen it on tv during motorcycle races...but...imho, you don't need to master
that technique to ride safely.  ( Do they even teach it during the motorcycle safety course most folks take? )

I was a motorcycle messenger for years, in CA lane splitting is legal.  Not at the high speeds I did it, but legal.
I spent years and years going from SF to Sacramento to San Jose and points in between, at high speeds in lots of rain, and lane splitting, never once countersteering (unless of course, I just do it naturally, which is possible).
Every time you started a lean to go around a corner, you countersteered. It IS natural, but it's been my experience that actively thinking about it sometimes helps.  When I took the TEAM Oregon class last year, it was the second thing they covered and they repeated it all day.

Hope you get the bike sorted Phyphor.
"The greatest mistake you can make in life is to be continually fearing you will make one."

Guest

  • Guest
86 Suzuki GSX 750(?) problems.
« Reply #11 on: March 23, 2006, 03:52:34 PM »
GS, I love you man Smiley but you're going to get somebody killed.  Maybe it was natural for YOU but not for most people.

Arright.

Here's what's going on.  If you want to corner, you have to lean.  To corner right you have to lean right.  You do that by cranking the bars left.

What happens is, you "jerk the rug out from under yourself", sideways.  The bottoms of your tires go left, you fall right.  And then catch yourself by straightening the bars once you're at the appropriate lean angle.

There's a "reverse countersteer" too: if you're already leaning right, cranking the bars hard right will "kick you upright" and rapidly straighten the curve.

The reason you MUST learn this is simple: if you're in mid-corner and come up on trouble, be it a car pulling out, oil slick, gravel patch, whatever, countersteering or the reverse countersteer will let you change cornering angles in mid-corner.

If you don't know how to do THAT, you're going to die if you stay on two wheels long enough.  OK?  It's a matter of "when".

Gunsmith, you need to go read a book on this stuff.  Keith Code's "A Twist Of The Wrist" is widely viewed as the best work on the subject.  Until you do, I am asking you please NOT to say what you just said above, because if you spew that on enough forums you're going to kill somebody.

Sidenote: if you're already in mid-corner and you see junk coming at you, if you have a choice between diving inside it by countersteering deeper or going upright and passing it on the outside with a reverse countersteer, you should favor the latter.  Reason being, the closer you are to vertical the more braking you have available.  At "full tilt boogie battle lean" you have basically no brakes - you're already asking your tires for all they've got with the cornering forces, add even semi-serious braking and you wipe out.  

In extreme cases (you're really getting squidly!) you can't even roll off the throttle without unweighting the rear end and risking the rear end breaking loose.  In more rational street riding, you can usually feather the rear brake some in mid-corner if you've got the skill to pull out of a mild rear-end slide.  This precise control over the back brake is why a lot of fast street riders deliberately weaken their rear brake, so the transition to "feather it" isn't as abrupt.  They then use the rear for fine control in mid-corner.  I was always able to control a normal rear brake and didn't bother even back 18 years ago when I was streetracing Cheesy.

Folks, I haven't owned a car in...lesse, over 16 years and I think a bit longer.  Bikes only.  I know what I'm talking about here: if you can't countersteer get the heck off the street until you can.  Go to the biggest parking lot in town and practice until it's natural.  

Or take one of the classes because yes, they teach it in EVERY class including California's MSF program.  Only gotcha there is, they sometimes teach a "gelded version" called "push on the handlebar that you want to lean towards".  This works, and it IS countersteering, but it also leaves you with less stability at the nose.  I prefer to teach cranking on the bars with both hands, equal pressure to stabilize the front end but...that in turn is basically prepping you for race or near-race conditions.

Which in an emergency you might encounter...

gunsmith

  • I forgot to get vaccinated!
  • friend
  • Senior Member
  • ***
  • Posts: 8,179
  • I'm sorry, Dave. I'm afraid I can't do that.
86 Suzuki GSX 750(?) problems.
« Reply #12 on: March 23, 2006, 06:50:43 PM »
"Gunsmith, you need to go read a book on this stuff.  Keith Code's "A Twist Of The Wrist" is widely viewed as the best work on the subject.  Until you do, I am asking you please NOT to say what you just said above, because if you spew that on enough forums you're going to kill somebody."

Ok, Jim I promise not to say another word on the subject untill I read that book, but only because you love me ;-)
Politicians and bureaucrats are considered productive if they swarm the populace like a plague of locust, devouring all substance in their path and leaving a swath of destruction like a firestorm. The technical term is "bipartisanship".
Rocket Man: "The need for booster shots for the immunized has always been based on the science.  Political science, not medical science."

Guest

  • Guest
86 Suzuki GSX 750(?) problems.
« Reply #13 on: March 24, 2006, 07:35:19 AM »
Quote from: gunsmith
I have to gentley, politely and very respectfully disagree with Jim on the subject of countersteering.
I'm not saying it doesn't work, I've seen it on tv during motorcycle races...but...imho, you don't need to master
that technique to ride safely.  ( Do they even teach it during the motorcycle safety course most folks take? )

I was a motorcycle messenger for years, in CA lane splitting is legal.  Not at the high speeds I did it, but legal.
I spent years and years going from SF to Sacramento to San Jose and points in between, at high speeds in lots of rain, and lane splitting, never once countersteering (unless of course, I just do it naturally, which is possible).

I've been in 8 to 10 accidents  all at very slow speeds  two involved looking at girls mini skirts and trying to drive real slow ( so I can look longer ) the rest  were all under 25 mph,4 involved braking on sand and gravel or loose small pieces of cardboard (all in SF) 2 were those darn cable car tracks in SF (turning  when wet over them is to be avoided) and a couple of losers making illegal left turns in front of me causin me to dump it.

So in my opinion if you can learn counter steering, more power to ya.   If you can't,  take the motorcycle safety course and don't sweat it.
It is pysically impossible to put a bike into a turn at speed without countersteering, it is simply not something yo can choose to do, it is something that one doesnt really think about, but I assure you that if you didnt go skittering off the roadway you were doing it. You can test this yourself; Ride along the roadway at say 30mph in the left lane, now take your left hand off the grip and gently push with your right hand, which direction did you go?

Phyphor

  • friend
  • Senior Member
  • ***
  • Posts: 2,328
86 Suzuki GSX 750(?) problems.
« Reply #14 on: September 27, 2006, 10:37:49 PM »
One - The bike is fixed

Two - I have no problems cornering it, ... anymore...


And finally, for those that asked, I'm about midway between Fresno and Bakersfield, CA.
"You know what's messed-up about taxes?
You don't even pay taxes. They take tax.
You get your check, money gone.
That ain't a payment, that's a jack." - Chris Rock "Bigger and Blacker"
He slapped his rifle. "This is one of the best arguments for peace there is. Nobody wants to shoot if somebody is going to shoot back. " Callaghen, Callaghen, Louis La'mour

41 Redhawk

  • New Member
  • Posts: 31
86 Suzuki GSX 750(?) problems.
« Reply #15 on: September 28, 2006, 08:12:03 AM »
Quote from: Phyphor
One - The bike is fixed
Hey, that's not fair....you didn't say what was wrong with it!

Phyphor

  • friend
  • Senior Member
  • ***
  • Posts: 2,328
86 Suzuki GSX 750(?) problems.
« Reply #16 on: September 28, 2006, 04:12:27 PM »
Bad front wheel bearing,
"You know what's messed-up about taxes?
You don't even pay taxes. They take tax.
You get your check, money gone.
That ain't a payment, that's a jack." - Chris Rock "Bigger and Blacker"
He slapped his rifle. "This is one of the best arguments for peace there is. Nobody wants to shoot if somebody is going to shoot back. " Callaghen, Callaghen, Louis La'mour

Lobotomy Boy

  • New Member
  • Posts: 35
86 Suzuki GSX 750(?) problems.
« Reply #17 on: September 28, 2006, 05:23:13 PM »
I figured this was a bearing issue. Given the age of your bike, I wouldn't be surprised if you don't end up replacing the swingarm bushings and steering-head bearings in the relatively near future.

I've always liked that era Suzuki. I've had a bunch over the years. I hit a deer on one in 1996. Is your bike an E or an ES?
Raging against tyranny since 2006.

InfidelSerf

  • friend
  • Senior Member
  • ***
  • Posts: 884
86 Suzuki GSX 750(?) problems.
« Reply #18 on: September 29, 2006, 05:06:50 AM »
gunsmith said
Quote
(unless of course, I just do it naturally, which is possible).
You got it GS.  Because counterstearing is pretty much as set in stone as gravity.

Of course that is because when you ride a motorcycle you are basically riding a gyroscope.
The only time counterstearing on a motorcycle may not apply are some of the long low cruisers and choppers.  
But even they experience that point where counterstearing works. Just not as often.

His slabside gixer, will fight him constantly until he learns and embraces the concept.

As for your problem.  If I bought a used '86 ANYTHING  I'd replace ALL wheel, steeringhead, and any other vital bearings outside the engine. Period.
The wobble you decribe.. my money is on the steeringstem bearing. But wheel and swingarm bearings can cause said wobble as well.

However keep in mind it's a used sportbike, which means it has no doubt seen wheelie time.  And when squids learn to wheelie, they slam the front end down often. (check your fork seals too) Which is very hard on those bearings.

BTW If you want to save some serious cash, don't bother calling your dealer for those bearings.  Contact your local bearing supply warehouse. When you pull those bearings they will have manufacturing markings on them which you can use to find the replacement. Or just mic them and send the dimensions to the bearing supply shop.  
If I remember correctly they were tapered rollerbearings on the steering stem.  Just check them out before you call.

However if you are not all that mechanically savy... then just take it in and have them replaced. Since the wheel may have to be pressed in.
And improperly seated bearings will cause you more problems down the road.. possibly even fatal.

Lastly don't forget your leather and helmet. And any if not all of Keith Code's books.  Read, practice on an empty parking lot. And get yourself into an MSF riders course ASAP. Not only will you learn some things but most insurance companies offer discounts for riders who take them.  
Then when you are a bit more comfortable I highly reccomend getting on the track and take in a track day.  You don't have to race or want to race to get alot out of a day on the track.

Oh yeah, welcome to the two wheel world Smiley
The hour is fast approaching,on which the Honor&Success of this army,and the safety of our bleeding Country depend.Remember~Soldiers,that you are Freemen,fighting for the blessings of Liberty-that slavery will be your portion,and that of your posterity,if you do not acquit yourselves like men.GW8/76