Page last modified: 09/03/08

Performance

Note: Email addresses and links listed in this Q&A section may no longer be valid!

DATE: November 7, 1999
QUESTION: What Carbs Am I Looking For? - 1981 GS1100EX

I understand that flat-slide carbs from a "stock GSXR" will plug right in to my GS1100 intake mainfolds/head to add some serious POP to my old dinosaur. Does anybody out there know just which year(s) and model(s) (750 or 1100) will work for this transplant? If there are several options, which ones work best? How about jetting info? NEED A LITTLE HELP HERE. My bike has Wiseco 1134cc slugs, stock head & cams, and a V&H 4/1 pipe. I'm guessing that K&N pods are the way to go with this setup. Thanks if you can help. This site is THE BEST! GS'S FOREVER!

RIDER: Ted Radke

REPLY: Scott Horner
We have found that these flatslide CV's give the GS a strong low end shot in the butt. Any year GSX-R 1100 or 750 will work up to 92. I suggest 89 or newer. You will have to run individual filters on them. The 36 mm seem to work the best on a mild motor. The 36's are more plentiful, and cheaper than the 38 mm of the 750. You will need a jet kit also, it will save you a bunch of time. I have a few sets if you need one.

DATE: November 7, 1999
QUESTION: Road racing?? - 1979 GS1000EN

I bought a '79 GS1000EN 'rat' with the intentions of building a road race bike. It's completely torn down, every last nut and bolt, to a bare frame on the bench. Falicon did the crank, and I'm putting in a Wiseco 1085 kit, cams, carbs, etc. Horsepower's great, but you go nowhere if it doesn't handle. I got a magazine article from 1979 analyzing Wes Cooley's bike, Looks like pretty extensive frame and suspension work had to be done. Am I nuts, or is this project going to break the bank and still not be competitive against say a Ducati 900? Or will gobs of horsepower on the straights have to even things out?? Can those thrilling days of yesteryear live again? Or do I need Pops Yoshimura on the payroll? Open to suggestions...

RIDER: Rick Patrolia

REPLY: Joe Lanfrankie
I have pursued the path that you're on and have a few comments. My '78 GS1000 engine has a Falicon crank, Wiseco 1086 kit, cams, porting, smoothbores, Yoshi header, etc. all carefully assembled by a good builder and is everything that I hoped it would be.

The frame was powder coated without any modification.

The suspension was fitted with a GS1100 aluminum swingarm, Fox shocks, and Progressive springs. Wider rims allow modern tires. The front brakes have EBC rotors and DP pads with stainless lines. This winter the forks will get a thorough rebuild with Gold Valves and Shamban bushings and seals.

Superbike bend bars, a custom cutdown seat (a necessity as the acceleration is much easier to handle with some butt pocket to keep me from sliding off the back), quarter turn throttle, and rearsets have made the riding position just right. The stock pegs are too far forward for body steering.

This project has consumed more than enough cash to buy a good used 900SS or a new 600 sportbike.

A recent day at Seattle International Raceway with Reg Pridmore's CLASS school was quite enlightening. The GS will out drag a Yamaha R6 or a Honda Superhawk down the main straight, much to my amusement and their dismay. Hayabusas and R1s blow right past me.

At the end of the straight turn one leaves the drag strip portion with a ripple in the pavement transition. At about 135 or 140 indicated the bike is flat out terrifying hitting those ripples leaned over. The bars start to twitch - not a full tank slapper, but enough to let you know it's time to rethink the line (and tighten up my shorts). The rest of the track is fun, but the GS is no competition for a modern sportbike in tight turns especially if the pavement is rough. Smooth roads with big sweepers are fast and comfortable if steered with the knees as Reg teaches. Horsing the handlebars around counter steering twists up the frame and starts the kind of oscillations that make the bike very scary. This makes sense as Reg learned to race on this vintage of bike.

Hard braking deflects the skinny forks enough to make a noticeable spring back if the brakes are let off too quickly. Best not to try trail braking into the turns, get all of the braking done upright and get on the throttle as the bike is leaned over. The abrupt nature of the smoothbore carbs throttle response make this even more important.

If you are serious about racing look into the class that you will be in. Modified over 1000cc will probably put you up against bikes like the Yamaha R1 and Kawasaki ZX9-R, both of which bone stock have significant weight and horsepower advantages over the most radically modified twenty year old muscle bike.

A neighbor of mine just bought a "totaled" Honda CBR600 with less than 2000 miles at auction. The original purchaser slow speed low sided and the bike slid under a parked car, breaking every piece of plastic in the bodywork but causing no mechanical damage. The guy figures that with pattern bodywork, brake lines, safety wiring, and extra sticky tires he will have less than $3000 into a bike that fits into a couple of racing classes, is stone ax reliable, and will have no problem turning lap times lower than my Suzuki. If he pushes too hard and crashes it (what Keith Code calls "Road testing your leathers") repairs will be relatively easy. Think of the cost of replacing the right side engine covers, ignition, and crankshaft on your GS after a long slide. Case guards hit the road much too soon for fast riding.

I love riding the my Suzuki - the engine is more fun than is legal, it sounds glorious at full throttle and enough RPM to get the cams working, it's reliable, it's easy to work on, and it always has a couple of guys peering at it when I take it to Vintage Motorcycle Enthusiasts meetings. It's the bike I wanted back before I had the money to own it. Modern bikes are much less challenging to ride fast, but to me not as entertaining. The horsepower will let me surprise other riders and keep up with almost any sane person until the road gets too twisty and rough.

Get ahold of a copy of Kevin Cameron's "Sport Bike Performance Handbook". It helped me plan the work and to get results that I'm very happy with.

Any chance I can get a copy of that article on Cooley's bike?

DATE: September 6, 1999
QUESTION: Cam timing - 1981 GS1100E

I have recently advanced my cams by 3 degrees to bring down the power band to a lower rpm. I have heard that on old Kawasaki's that the intake should be advanced 5 degrees and exhaust retarded 2 degrees. What is the proper way to do this and what is the result in regards to each cam? Should I be retarding my exhaust cam?

RIDER: Dave Lambe

REPLY: Scott Horner
We have found the 107 intake and exhaust for street/strip use on the GS motors as a great set up. If you want to gain bottom end torque, advance the exhaust cam by 2 degrees from stock. Good Luck.

DATE: August 21, 1999
QUESTION: Performance ratings wanted - 1979 GS1000E

I have a 1979 GS1000E that I recently purchased in very good condition. I was interested in finding out the horsepower rating and torque rating. I would really appreciate an answer thank you very much Dean.

RIDER: Dean Christian Nolde

REPLY: Joe Lanfrankie
The August '99 issue of Classic Bike magazine has a ride report on a '78 GS1000E. The statistics page says:

87 bhp (claimed) 
61.3 lb-ft (claimed)
135 mph top speed (claimed) 
0 to 60 mph in 3.5 secs (claimed)

DATE: August 21, 1999
QUESTION: Engine swap - 1978 GS750E

Would a GS1000 engine fit into a 1978 GS750 frame? If it does, would the handling be sacrificed? Thanks, Paul.

RIDER: Paul Sokolovas

REPLY: Jordan Rodier
Yes, it will fit. You will have to fabricate new rear and bottom engine mounts but the rest is relatively easy. I don't know about stock suspension, I had previously mounted the front end from a GSXR and the combination seems to work well ( lots of go and lots of stop).

DATE: August 8, 1999
QUESTION: Ignition advance governor - 1982 GSX1100EZ

Does the spring in the advance governor get weaker in time thus not providing the accurate timing? While having dinner I thought about and without opening the signal generator cover assumed that it has a spring. If the weakening happens should I replace it with the stock one, as I'm looking into Dyna S ignition and coils?

RIDER: Luka Bastic

REPLY: Frank Perreault
Yes, the springs can weaken over time.  That's why everyone one has gone to pure electronic ignition systems.  If you're looking at going with the Dyna S ignition I would say that that is a great move.  I wouldn't bother with the stock system.
REPLY: Scott Horner
The Dyna S is the way to go for trouble free ignition components, but it still utilizes the stock spring type advance mechanism.

DATE: June 18, 1999
QUESTION: Correct gearing? - 1982 GS1100GL

When I am riding on level roads @ 55 to 60 mph my RPM is about 4000. It seems rather fast to me, what should my RPM be at that speed? Could someone have changed the factory gears? It has more bottom end speed than I will ever need and I would like to bring down the RPM to reduce some of the vibration if possible. Suggestions??

RIDER: Michael Hendricks

REPLY: Bill Patten
That engine speed is correct for that speed. Bikes of that era were geared to get good quarter mile times for the magazines. The only easy change is to put a 17 inch rear wheel from an 850 or 1100 G model. That will drop engine speed at 60 to about 3800.
REPLY: Chris Skanderup
Sounds right to me. I've got a 650 that revs a grand higher than yours, and >my father-in-law has a 1000 shafty that turns same as yours. Because your >bike is a shafty, you don't have much of an alternative other than maybe >higher profile tires (if you can find the right size).

DATE: June 29, 1999
QUESTION: Tuning 1979 GS1000S

I have a 79 GS1000s,(the one with flat slide carbs) and will be taking the head off soon to change the valve seals. It has a K&N filter in the original air box, and a Marving 4to1 race pipe, otherwise it's standard. I had it on a dyno last week and it made 71 BHP. Does anybody have any suggestions as to simple effective ways of tuning the engine to increase the power? Does porting/flowing the head do much? What should I expect to make at the back wheel? I would like to enter sprint races so a good make over would be useful. Thanks Chris (Isle of Man)

RIDER: Chris Kirk

REPLY:  Joe Lanfrankie
The ports in the GS1000 motor are old fashioned poor quality casting, very rough and cobby, so substantial power can be gained by porting IF the person knows what they're doing. This skilled hand workmanship is expensive, and only pays off if the rest of the fuel/air system (carbs, jetting, cams, etc.) is improved to match.

Before you do anything get a hold of a copy of Kevin Cameron's "Sportbike Performance Handbook", available from Barnes and Noble or Amazon.com. Read it until you understand it before you do anything to "improve" that wonderful bike. Then consider leaving the GS as a clean stock classic, and getting another bike to race.

My '78 GS1000 has an open checkbook near full race motor (bored, welded crank, cams, ported, smoothbores, electronic ignition, header, etc.) with wider rims and modern sticky rubber, and frankly the old wimbly frame scares the bejesus out of me when I push it hard.

DATE: May 21, 1999
QUESTION: Drag Racing - 1982 GS850

I want to convert a 1982 GS850 into a drag bike (no street use). What is the viability of using a shaft driven bike for this purpose? I'd welcome any hints or advice on using the 850 for drag racing.

RIDER: Jeff Chiyka

REPLY:  Malcolm Evans
Forget it man - the extra weight will just not make it competitive, there are no big bore kits available and very limited performance parts.

The 850 was created as a tourer, over bored from the 750 to compensate for the extra weight of the shaft drive - for proof, the 850 top end will fit onto the 750 bottom end.

Buy a GSX 11 instead.... an EFE (GS 1150) for ultimate performance!

DATE: September 27, 1998
QUESTION: Is this really a turbo?  - 1983 GS450T

My brother recently purchased a l983 Suzuki GS 450 T. It is in mint condition with low, low mileage. The manufactuer's wind screen indicates that this model is a turbo. What can you tell us about the turbo model and how can we tell if in fact it is a turbo model? Thank you.

RIDER: Heather Murphy

REPLY: Zack Schultz
Suzuki only made a Turbo in 650 flavor. Sounds like someone used an XN85 (that's the model designation) windscreen. However, in the unlikely event that a turbo has been retro-fitted, they require rather distinctive plumbing. The exhaust will feed off all cylinders to a central pipe which in turn feeds the turbo. From there, if you look at the output side, there will be the muffler plumbing on one half, and a pipe feeding into the carbs on the other. There will also be a distinctive whine coming out the exhaust due to the high rpm's of the turbo unit. Somewhere there will be a boost gauge - usually on the dash, put if it's a home built, no telling.

DATE: September 27, 1998
QUESTION: Performance info needed - 1983 GS550

I have a 83/84 GS 550 es that I am racing in AMA/CCS sportsman competition here in Fla. Do you know of any place that I can get tech tips for engine updates, help on those miserable dualthroat carbs, cam degreeing numbers, performance parts availability, etc.? I can find listings for headers, jetkits, and such, but I would like to know what was done to these bikes (the 550tscc)back when they were new. Do you know if Yoshimura, or Yoshima, ever fiddled with them? Any help that you can give me would be GREATLY appreciated!

I have the chassis working pretty well at present, with Katana forks, brakes, and wheels, and GSXR shock/w modified linkage. I would like a little more guts in the engine though. At present the carbs are set up with 118 mains, 37.5 pilots @2-3/4 turns out,and sc15 needles. I'm running a yoshi header, a k&n filter, and undercut trans. I have the ignition advanced 4deg.On the top end it's good for about 125mph as geared. But I would like more grunt in the mid-range. I realize this is all pretty confusing, but if you have any insights, I would sure be interested in hearing them.

RIDER: David Starling

REPLY: Zack Schultz
I have an 84 GS550 myself. I'll start with your last comment first. These things were supposedly good for 125 new. I saw this myself (indicated) several times. And I'm glad someone is campaigning one. Tuning the carbs. Think of them as siamesed singles and the problems minimize. Everything is separate except the float bowls. Hence, the bowls are undersized. Make sure that there is enough fuel flowing to feed the motor.

Kevin Cameron once wrote that some buzzy engines (and this qualifies0 have trouble with fuel frothing at sustained high R's (like Daytona). Foam doesn't lend itself to accurate jetting. Adding weight to the carb dampens it's vibration and frothing is eliminated. I think he said something about a pound of welding rod wrapped around the float bowl. I did speak to someone a few years back in the Galveston area that was racing one of these. I don't keep up on the class rules, but he was using 600 Hurricane pistons (63 mm) in the engine. These are the same size that Wiseco was using in their big bore kits, so there's metal to go that far over (+3mm). Good luck and pass along results.

DATE: September 27, 1998
QUESTION: More power wanted - 1979 GS750L

First, you guys are doing a wonderful job with the site. Now down to business.

I have a 79 GS750L and although I love the way it runs, I do a lot of two up riding so I would like some more juice to it. My question is this....I am going to make carb mods and put on a Vance & Hines pipe. As far as the carb mods go, would I get more performance from a Stage 1 jet kit on the 26mm carbs I currently have or would I be wiser to change over to bigger carbs, say ones from a 78 GS1000? How big are the carbs on the 1000? Am I looking at more frustration with the kit or the whole new carbs? Are the carbs from the 1000 bolt ons or am I looking at serious problems in getting them to fit? Any help would be appreciated.

Thanks and keep up the great work with the site!

RIDER: Nate Dickerson

REPLY: Zack Schultz
I'd recommend getting the carb kit for the stock units with a different pipe. Changing to the bigger carbs would be a real jetting nightmare, and to be honest, unless you are doing something to the engine to pump a WHOLE lot more air thru, the stock ones will do a splendid job.

DATE: September 26, 1998
QUESTION: Funky ignition at high revs - 1979 GS550E

In 1981 I bought a 1979 GS550E. It’s rusty, it’s got some problems over that 17 years I use it (but only 81.000 km/50.000 miles), but it is still running and I’m fond of it.

Since a short while I experience problems with the ignition, but it occurs only with hot engine. After warming up the engine, everything seems to be fine for a while. Engine can be revved up to what it is designed for, up to 10.000 rpm seem to be ok if you want to push it hard.

When it’s getting hot, things change. Up to some 5.500 rev’s everything still seems ok, then interrupts on detonation begin and increase the more I rev it. I can’t exactly identify, but I think the phenomenon is spread over at least 2 cylinders. I can rev up to some 8000 or 9000 rev’s, but it’s not worth it: There is no increase in power due to interrupts in ignition. The contact points look good and are quite new, as well as the timing. Spark plugs have some 2000 - 3000 km, which is not much. Do you have any idea to find out what it is, without giving it into service ? Thanks for help

RIDER: Ralf Seyer

REPLY: Chris Hunter
I have a similar problem on my 1100. It is caused by a burnt valve. Basically one (or two if it's two cylinders misfiring) of the exhaust valves is not closing fully. Adjust the valve clearances and then have a compression test/leak down done.

DATE: September 26, 1998
QUESTION: How to get more speed - 1982 GS850GL

What do you suggest I do to speed up my 1982 GS850GL with 25k miles on it?

RIDER: David Hutchinson

REPLY: Michael Saxon
Jack it up and drive a GS1100 under it.

But seriously, a stock GS850 in good shape should make more than adequate power given its handling characteristics. If you are unhappy with the power output, the first thing to do is check compression and do a leakdown test. If compression is within spec, you do have some options. 850s respond very well to jetting changes, especially if done in concert with pipe changes. If you do replace the stock pipes, you will need to increase the main jets at least one size, and you will probably want to raise the needles. I have heard good things about the Dynojet kit, although I have not found it necessary to rejet my bike (although I did richen the idle mixtures to improve drivability - the bike now pulls smoothly in all gears from 1000 rpm). KEEP THE AIRBOX. Removing the airbox will create all sorts of exciting flat spots in your torque curve. The stock air filter is a very nice oiled-foam unit, although you could replace it with a UNI element. Good Luck!
REPLY: Frank Perreault
See various articles in the Q&A-Fuel/Exhaust and Q&A Performance sections about the "Keep the airbox" comment.  There seems to be a bit of controversy concerning this issue.

DATE: August 24, 1998
QUESTION: How to do a wheel alignment

I have a 1980 GSX 1100 ET and a 1981 GS 1100 LT How do I go about aligning the wheels? (all bearings have been renewed) Clymer shows that I can sight along the drive chain is there a more accurate way of rigging the bike?

RIDER: Bruce Roy

REPLY: Frank Perreault
Bruce answered his own question.  This is how to do an accurate wheel alignment!  In fact, it is the method that the lots of race teams, both motorcycle and stock car use.
REPLY: Bruce Roy
I sat the bike on its center stand with the seat removed and with the assistance of a small floor jack and placing a spirit level across the frame (several places) I leveled the bike laterally. By placing the spirit level vertically (it has a vertical and horizontal bubble) against one of the front brake discs you can find a definite central position (thanks to the steering head angle), the front wheel is now aligned straight with the frame I then ran a string line suspended between two stable stands (actually one was my garage door and the other was the frame of my portable compressor) at an uninterfered distance the full length of the bike at roughly the same height as the axles and using an accurate ruler a bit of juggling and some patience I aligned the string parallel with the beads (front and rear) of the front wheel then took measurements against the rear wheel beads and as I suspected the front of the rear wheel was around 7 mm out compared to the back of the wheel I adjusted this out and (the swingarm marks are about 1/2 division different now) and the bike road tested like a new one. Its a simple task that makes a heck of a lot of difference to the bikes handling and all is needed is a string line, a builders spirit level and an accurate ruler.

DATE: July 13, 1998
QUESTION: Wheel swap - 1983 GS1100E

Can someone answer this question? I have a 1983 GS1100E I'm thinking of buying a rim off a 1150 I understand the modification's needed. This will allow me to run a larger back tire . Does the 1150 use the same size front wheel as my 1100 or is it the same using the larger back wheel? How does the bike handle with a larger wheel?

RIDER: Brian Underwood

REPLY: Scott Horner
The GS 1150 had two wheel sizes for the front and rear. For the '83 California model ('84 for the rest of the country) the sizes were 2.50X16 front, 3.00X17 rear. All other years/models were riding on 2.75X16 front and 3.50X17 rear. If you did put the 16" front wheel on the '83 1100 you would notice considerably quicker steering. The rotors are different sizes, your caliper mounts would need to be changed also. The speedo drive unit is interchangeable, and you would need to find a fender substitution. The 1100 looks a little funky when lowered that much. The 1150 fender does not fit (too wide). As far as adverse handling characteristic from applying a 1" wider wheel, you really won't notice a change. Good Luck!

DATE: May 25, 1998
QUESTION: Bunches of performance questions - 1983 GS1100G

I have a 1983 GS1100G with about 10K on it.  I'm wanting to modify the stock air box to utilize ram-air technology.  I'd be doing this homemade.  Or would I be better of using individual K&N filters?  I would also like to put a new exhaust system on it.  What would these mods. do to the performance of the bike.  Would the carbs (Mikuni CV) need to be re-jetted?  Why/why not, what does this do and how would I know what size jets to purchase.  Would any one of the mods. by itself necessitate carb jetting, could I get by without re-jetting? 

I have also heard that adding heavier oil to the forks enhances handling, truth or myth? 

I'm not sure how many valves per cylinder.  I would be interested in any ideas anyone has for squeezing as much power out of this muscle machine as possible on a tight budget.  I also like to do most of the work myself.  Besides isn't that the joy of it?

Does anyone know where to get stock specifications for this bike (bhp, compression, torque)?

RIDER: Adam Raker

REPLY: Frank Perreault
Well, you're sort of behind the rock and a hard place if your looking for tons of horsepower without spending money.  Like the racers say, "Speed costs money!".

I'm not sure what you mean about ram-air.  While a K&N increases air flow to the carbs, it certainly isn't 'Ram-Air'.  Ram-Air is accomplished through scoops and hoses.  Because of the speeds necessary to make it work, turbocharging and supercharging came about.  Neither is cheap. 

If you go to K&N's you should replace the exhaust also in order to take advantage of the freer breathing.  And yes, you will have to rejet.  As for sizes, you can get a DynoJet kit which includes the correct jets.  With that you do the work, but you get all the pieces lessening the chances of having to experiment with jet sizes.

Fork oil viscosity is dependent on your style of riding, the quality of the road, the air temperature and the suspension itself.  You would have to buy the various oil types and try them out yourself.  Just remember that fork oil measurements are extremely critical when trying to figure this out.

4 valves per cylinder.  K&N's along with a new exhaust will give you the cheapest improvement but it still isn't cheap.  K&N's are about $120 for 4 and an exhaust will go for $250 - $500.

No idea on the stock specs.
REPLY: Adam Raker
Thank you for your reply to my questions. To clarify what I meant by ram-air, I was going to modify the airbox and route hoses from the front of the bike into the airbox. Just by looking at the stock airbox the "channel" that the air is pulled through seems pretty small to me. I plan on keeping this bike a long time and hopefully be able to "afford more power". I'm also looking into adding an Accel Ignition Kit. About the exhaust, would I be able to put a canister on it with minimal mods. or am I stuck with a megaphone. This may be a dumb one, but are V&H megaphones better than stock?
REPLY: Frank Perreault
In order for ram-air to be effective you would need to be going 90MPH all the time to make it work.  I think it's cheaper going to K&N filters than paying bail money.  Therefore, in my opinion, ram-air is a useless proposition for a street bike.   Yes, racing megaphones are better than stock but remember it usually involves rejetting carbs and going to K&N filters.  As for whether they'll fit your bike, talk to the company selling them.  You'll probably need to measure you pipes before hand.

DATE: May 2, 1998
QUESTION: Handling problems - 1982 GS1000G

I have recently acquired a 1982/3 GS1000G in excellent condition,18000km.  My previous riding experience involved scratching on 250/350cc two strokes so the handling of the GS feels a little strange. One aspect alarms me ,and it is the tendency for the front end to shake for no apparent reason especially if one removes ones hands from the bars, the proverbial "tankslapper" which I believe was a problem with early British bikes. Also, on leaning into tightish corners the impression is that the bike does not steer too well.  Are these handling characteristics normal for these bigger heavier bikes or might I have a problem with head bearings etc.I have checked tyre pressures and equalized fork pressures at 15psi. Any owners experiences would be appreciated.

RIDER: Alan Dee

REPLY: Frank Perreault
There is going to be a BIG difference between the handling of a 450 pound bike and a 580 pound bike.  There will also be a big difference between a 1981 GS1100 and a 1997 GSX1100.  That is the nature of the beast.  Yes, the 1000 will definitely feel like a log compared to more nimble and smaller 250cc bike.

As for the wobble, this shouldn't happen.  The common causes of this are slop in the steering stem adjustment, bent rims, out of balance tires or tires that are not lined up straight with one another.

DATE: April 10, 1998
QUESTION: Lower bar conversion for a GS850G

I'd like to switch to lower bars on my 1983 GS850G. Has anyone done this? I'd like to use stock Suzuki parts, handlebars, cable , brake lines if possible. Any advice would be appreciated.

RIDER: Lou Veltri

REPLY: Frank Perreault
I've replaced my bars with a style called "BMW bars".  These place your hands lower yet retain the use of all the original cables.  Find yourself a bike shop that sells handlebars and will hopefully allow you to at least lay them on top of your existing bars to try them out.

DATE: April 10, 1998
QUESTION: High speed wobble

I have an 83 GS650GD with 19,000 K. The bike has run just great. However, starting   at around 85 MPH the front end starts to wobble back and forth. It gets really unstable. Judging from the tach I should be able to hit 120 MPH. It seems rock solid at lower speeds but as you hit 85 it gets down right scary!  I have new Dunlop K591 sports on the front and rear and they are great. I know the bike isn't up to par with the newer  bikes but I don't think this is normal. I was thinking maybe a fork brace?

Any advice would be much appreciated. 

RIDER: Wilbur Thompson

REPLY: Frank Perreault
This be caused for 2 reasons - out of balance tires or misaligned tires.  As for the out of balance condition find a bike shop that can do a spin balance on the tires.   They are hard to find but worth the trouble since a spin is more accurate.   Now for the misalignment of the tires - Do not use the marks on the swing arm to set the alignment of the rear wheel.  You need to string the tires or use some other method to insure that the rear tire is perpendicular with the frame and the front wheel.

DATE: March 22, 1998
QUESTION: More GS1000 questions

I just purchased a 1979 GS1000E with 55,000 miles on it for $550.00 - It runs well aside from being cold-blooded and running rich. It came with K&N filters [no airbox] and an aftermarket header. Unfortunately, the header has a small hole at the 4 to 1 convergence point which results in backfiring on downshift. So I have a couple of questions:

1.) Does anyone know of an aftermarket header for this bike, aside from the standard megaphone setup offered by Kerker?
2.) Does anyone have or know of a manual for this model bike? 
The only one I can find in print is for the shaft driven GS1000 and Amazon.com is searching for an out of print manual for my bike, but I'm anxious to get wrenching - the previous owner didn't even know what kind of valve adjustment the bike took, so I'm dubious about riding it until I go through the engine.

RIDER: Nicholas Reisen

REPLY: Ryan Biggs
I'm afraid I don't know enough to help you with your exhaust questions (I just got my '79 GS1000E a few weeks ago), but I do know of a manual for it. Haynes makes one for the '77 to '79 chain drive GS1000s. It's not specifically for the E model, and it's not the best manual I've ever seen, but the vast majority of its insights are applicable to the '79 E. I found a copy in my local bike parts shop, so hopefully you'll be able to find one easily as well.

DATE: February 15, 1998
QUESTION: Speedometer info for a GS1100E

I was the proud owner of a 1980 GS1100E in 1980. I sold the motorcycle in 1985. I have been bitten by the bug again and have just recently bought two GS Suzuki motorcycles. I now have a 1980 GS850G and a 1982 GS1100GK. They are both great motorcycles. The problem is that I want to buy a GS1100E like I used to have. My question, is there a European or Japanese speedometer available that fits the original speedo housing and shows the speed above 85 MPH. If so do you know the part numbers I need to make this conversion once I buy my GS1100E. That 85 MPH speedo really was a bad idea on such a fantastic motorcycle.

RIDER: Chip Howell

REPLY:  Bill Chandler
The speedo for the 83 model GS1100ED goes to 140MPH. The US law (forcing auto and bike manufacturers to limit speedo's to 85MPH) was repealed in 82 so the 83 model bikes had the "better" speedo.  I own an 82 model (GS1100EZ) and did not like this 85 limit.  I found a guy scrapping out his 83 and acquired the instrument cluster.  Removing the speedo was straight forward, however you need to be very careful with the wiring, lights and such.  I also reposition the OD to reflect the mileage on the current unit.  This was a bit of a  pain, but I could move the numbers by using a paper clip, just be careful!!  The result is OEM look with 140MPH!!  Too cool.

I have a "Ian Smith" report on the Suzuki GS1100 series bikes.  This report is a compilation of various Motorcycle mag articles published in the early 80's.  The report show the 80, 81, 82 and 83 models.  The instrument cluster for the 80 and 81 models seem identical.  The cluster for the 82 model is very different. The 83 model is the SAME at the 82 model (except the higher reading speedo).

I'm copying this reply to Frank (another site editor who owns an 81 GS1100) for his input.   Hope this helps'.
REPLY: Frank Perreault
If my memory serves me right, I believe that Bill is correct on this.  I remember wanting to change my 81 speedo for an 83 and found out it wouldn't fit.

DATE: January 30, 1998
QUESTION: 650/1100 engine swap

Will an 1100 motor fit in a 81 GS650G frame?

RIDER: Marty Palmer

REPLY: Frank Perreault
I'm almost positive that it wouldn't fit.  Even if you could do it you wouldn't want to.,  This is due to the negative and possible dangerous effects the horsepower of an 1100 engine would have to the 650 frame and suspension.

DATE: November 4, 1997
QUESTION: Drag racing

I want to start drag racing my GS 1100 in the street ET class. what are some of the modifications that I will have to do.

RIDER: J. E. Small

REPLY: Frank Perreault
You are going to need to take a trip to the track that you plan on racing at and get a rulebook. It doesn't make sense to got through investing $$$ if what your doing will end up being illegal for that division. So get the book and it should tell you what you can or can't do, legally.
REPLY: Suz1200@aol.com
Hi. Just found your page yesterday. Tried to respond to this person and the mail was returned. So, I'll tell you and maybe you can post it. I drag my street GS1100EZ and have helped build my friends ET. So, I've learned the $$ hard way what this bike needs for racing.

First, the clutch basket needs to be reinforced. They are weak in stock form, my friends bike even had a new Suz unit when he bought it because the dealer sold a Katana that blew it's basket on the way home! So they cannibalized his and installed a new unit when it arrived. It only lasted a year before it too broke. Mine was cracked upon inspection, so I got lucky. Now I have a reinforced one. The procedure entails acquiring a rebuild kit from Falicon. This kit includes new rivets, hd springs, and a steel backing plate. The rivets are welded in when assembled. The basic weakness of the design is the helical-cut primary drive. This produces a side force on the clutch. When modifying the motor for serious power (over 160hp) it's necessary to convert to a straight-cut primary drive to prevent disaster.

Next comes the roller crank. Since it's a pressed-together multi piece item, it can shift out of phase. Even the 83 model, which had a factory welded crank, can go out because the factory job isn't as thorough as a race shop is. I know some of the bikes were repaired under warranty, but some weren't, like mine. It was twisted when I bought the bike, and just got worse till I tore the motor down and had the crank trued and welded. To see if this has been done, remove the clutch basket and check the crank cheek by the primary gear. The weld material should be evident.

Another must-have item for racing a GS is a rev limiter. These are inexpensive at $60 from Dyna electronics. The bike does not have one from the factory, and a missed shift or powershift that goes wrong can zing the engine to high rpm. If an alternator rotor is used, the limit must be set no higher than 11000 RPM. This is because the rotor end of the crank can break with the weight of the rotor out there. Feel free to e-mail me to discuss any details.

DATE: July 21, 1996
QUESTION: Top Speed 850L

I own a 1980 GS850GL. In 5th gear at about 5500 RPM, the bike tops out at about 68-70 MPH. When I give it more throttle, it bogs down. Down shifting to 4th doesn't help - it just wont go any faster. I've cleaned the jets and the valve clearance was OK. Would changing jet sizes help or is this top speed for this model? Thanks!

RIDER: Stan Chapman

REPLY: Peter Huppertz
No... a fine 850 should easily do something like 110mph. Mine (a GS850GT) does approx. 120mph at 8500rpm. Look at the spark plugs to get an idea of what's going on. Black? probably too rich, or else ignition trouble. From what I hear, I'd experiment with the jetting first. I don't know where you're from, but if you live at a high altitude, the standard-jetted engine running too rich is not uncommon (the air is thinner), although I doubt whether it would make such a difference. If it's not the jetting, check the ignition (do you have the mechanic points ignition or the transistor version? How to tell? if you have a kick starter, you almost certainly have standard ignition; on the newer engines the kick starter was dropped).