1980 GSX1100's - Sreet fun and racing

Hi all,

Thinking of getting a GSX1100 for a bit of street fun, as a second bike
and to then also do some classic racing (forgotten era racing) here in
Australia.

Needs to be until 1980, Dec 31st. What should I look for in a GSX1100
1980 model?

Any good sites for these? I'm after information.


Many thanks,


James

aus_james at h0tma1l.c0m

 

http://www.thegsresources.com/

 

The GS-series had some annoying problems that could be solved if you
knew what was happening. These are all problems that I have seen or
heard about:

The Suzuki GS-series had problems with the alternator stator getting
fried, there you can buy aftermarket stators from Electrex USA, who
also make improved twin SCR voltage regulators...

The real culprit here seems to have been the male and female bullet
connectors on the ends of the stator wiring and the little adapater
pigtail on the wire harness. Its only purpose was to adapt the stator
connector to the voltage regulator that used a different style of
connection. The extra connections would corrode and loosen up and they
would get hot. A permanent magnet alternator doesn't know that it's not
charging the battery, it still puts current into the wires even though
all that's happening is that it's burning the wiring up...

While the wiring is frying, the stator can act like it's not connected
to anything at all, and create too much voltage. This excess voltage
punctures the enamel inulation on the windings and adjacent coils short
to each other...

You'd know this alternator problem was occuring when the battery was
always dead...

The early GS1100's had a habit of twisting crankshafts if you over
revved them and backed off. This problem was solved by welding the
outer counterweights on the 1983 models...

You'd notice that the engine vibrated a lot if the crankshaft was
twisted...

The alternator rotor would loosen up on the end of the crankshaft and
creep as the rider abused the RPM's. The crankshaft stub that the
alternator bolts onto gets eaten up and the rotor taper enlarges so the
crankshaft stub spins inside the rotor. This problem can probably be
solved by replacing the left side end of the crankshaft with a 1984
GS-1150 counterweight and a 1984 GS-1150 rotor. I suppose you'd need
the
GS-1150 stator too...

You'd notice that the starter spun but the engine didn't crank when the
rotor was loose on the crankshaft...

The GS-1100's also had a starter clutch problem associated with the
over-revving of the engine. The three special hardened steel bolts
holding the starter clutch to the back of the alternator rotor would
loosen up and snap...

You'd hear the starter clutch slapping on the back of the alternator
rotor, and pulling the clutch lever didn't stop the noise, so you knew
it wasn't the clutch basket...

If only one starter clutch bolt snaps, it can jam up the starter clutch
idle gear and throw the rider off the motorbike as it suddenly stops
the engine from turning...

Fortunately, I was in first gear going 10 miles an hour when THAT
happened. The centrifugal starter clutch used on Japanese motorcycles
seems to have been designed by Dr. Frankenstein. Gawd only knows how
many riders have been killed when one of those things seized up at high
speed.
Forensic engineers don't tear motorcycle engines apart to see if the
start clutch jammed up, they just look at the skid marks and figure
that the rider jammed on the rear brake and locked it up...

Anyway, the starter clutch bolt breaking problem can be solved by
welding the bolts to the alternator rotor. Of course they can never
been removed again, but that part of the starter clutch would never
need to be removed anyway.

The automatic cam chain tensioner would sometimes fall apart.
Vance&Hines used to supply a manual cam chain tensioner with a long
bolt and lock nut replacing the automatic parts. It's easy enough to
tap threads in the tensioner body and install your own hardware store
variety bolt...

A former professional drag racer told me that the clutch backing plates
would crack where the shock absorbing springs were. The backing plate
was just thick sheet metal and the square holes where the springs went
were punched through. The holes would crack at the edges...

Some large rivets in the clutch backing plate would loosen up and drag
racers would weld the rivets. Vance&Hines made billet clutch baskets
and
beefed up clutch baskets to solve those problems...

V&H also supplied a special clutch hub nut made of hardened steel to
replace the soft steel Suzuki nut...

When listening to the clutch hub rattling, I would always wonder if the
backing plate was cracking, but it didn't crack on me...

If you can replace the stock Mikuni CV carbs with something else, the
racers of the era were using Mikuni VM33 round slide smoothbore carbs.
They have a return spring like a garage door spring, it's a lot of work
to turn the throttle, and they stick under vacuum when you roll off the
throttle...

36mm or 38mm Mikuni radial flat slide carburetors with accelerator
pumps would be a better replacement carb...

There's more power to be had out of the engine by installing cams with
more duration, but if you're running on tight short race courses, a
better way to go is to advance the cam timing about three degrees on
both intake and exhaust cams so the intake and exhaust valves close
earlier. This gives you more mid-range "grunt" so you don't have to
shift gears as much. You just sit forward with your balls on the gas
tank and ride the
machine like it was a giant motocross bike, running deep into the
corner, squaring it off, and gassing out of the corner...

The lobe centers we used to degree the cam were 107.5 degrees.You can
slot the cam sprocket bolt holes with a rat-tailed file to move the
sprockets in relation to the cams...

 

[snip list of woe]

Sounds like a bit of a shit bike all in all.

--
Martin:
"For a minute there, you bored me to death."
VTR1000 Firestorm
TDR250 http://ukrm.net/BIKES/Yamaha/tdr250.html
martin dot smith nine zero three at ntlworld dot com

 

A guy who built a GS-1000 for drag racing told me that he had to spen a
lot of money on aftermarket parts to keep the engine from
self-destructing under the additional power. He said that if he'd known
that at the beginning, he would have bought a KZ-1000 instead...

But, in that era of 1980, if you wanted a 16-valve engine of 1100cc
displacement, what were your choices? The GS-1100 with its high tech
twin-swirl combustion chambers that used fuel more efficiently or the
rarer, hotter-running less fuel efficient Honda CB-1100F...

 

I don't know what the ratio is today, but in 2000, 16 of the top 20
NHRA drag bikes used the 1977-1985 series Suzuki GS engine, even after
it had been out of production for a number of years. There are
big-bore kits available up to 1500cc and larger, and a wide variety of
go-fast parts to support the engine.

Here's are some race results from late last year:

http://www.dragracecentral.com/DRCStory.asp?ID=39

Of the sixteen starters, all but three were Suzuki-powered. Some
engines were listed as "Suzuki GSXR", while others were just listed as
"Suzuki", but I don't know for certain what the difference is.

I've never raced one, but my wife's previous bike was a GS1100L, and
other than replacing the stator (a common problem with the GS series),
it never gave us a bit of trouble.