Dreaming of a better ‘77 Suzuki GS750
As my GS sits lifeless in the garage, as I search the web for what others have done with their GS’s, as my imagination runs more & more wild with what could be done, with ways to modify my bike & to make it more custom & trick… to have more of the qualities that I would want out of a streetbike. Well as if… as if only I could both manage it & afford it.
Maybe I should clarify what I mean by having more the qualities that I would want out of a streetbike, in case somebody happens to read that that feels a bike from the’70’s is just fine the way that it is. For me, when I think of motorcycles, I think of performance. Well, a bike from 1977 doesn’t really ooze very much performance any longer. In fact, it’s pretty well dried up. My previous streetbikes, in order, have been a; ‘90 Yamaha FZR600, ‘96 Kawasaki ZX7R, ‘96 Suzuki GSXR750, ‘00 GSXR600. Now I have my ‘77 Suzuki GS750 after a 6 year lay-off from streetbikes, as I’ve been off playing in the dirt with offroad bikes. So yes, as i let my mind wonder, I do feel that there are some things that my GS might be lacking, that maybe with a little bit of engineering, research, blood & sweat…. well and some swearing… I might be able to increase the “cool factor”, performance & trickness of my GS.
The bike that currently has inspired me the most would have to be Roland Sands “No Regrets”. Obviously my GS will never be up to this level in any way, yet I feel that I can pull some of the stronger attributes from his bike and try to implement them into my GS. Mine wouldn’t have the chrome V-Twin motor, or the $1,500 a piece rims, or even all of the one-off machined parts… but I could try & get the cool things, such as; inverted forks, wide rims and the aggressive road-racer seating position. More pictures and a story on the No Regrets bike can be found here.
Here are a couple other links to some other GS Projects out in the world. They aren’t necessarily the best one’s I’ve found, just what I can come up with quickly as I write this… but they can help give you an idea of what I’m thinking about.
http://forums.cycleworld.com/cycleworld/board/message?board.id=10&thread.id=11778&view=by_date_ascending&page=5
http://www13.plala.or.jp/xyz-yykrs/tofintsukuba.htm
http://www.robwilton.com/kats.html
http://www.katanaclub.nl/
So where does that leave me? Well, I have started a “Build Sheet” as I’m calling it. It is basically me compiling the things that I would like to do to the bike, plus a way to document the technical data that I come up with.
As of this current time, what follows are my thoughts & wishes for my own GS Project.
‘77 Suzuki GS750 Build Sheet
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Front-End – Complete GSXR750 (’01 or newer), GSXR600 (’04 or newer) or GSXR1000 (’03 or newer) with inverted forks, clip-ons, dual-disk brakes (would love radial brakes, but to keep costs down… they are not likely. Do not want the 6-piston calipers from the late 90’s… use the 4-piston ones).
Would I be able to use the GSXR controls (key-ignition, start button, kill switch, light switch, turn signals, horn & etc) with my GS wiring?
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Rear-End – Complete GSXR (’01 or newer) rear wheel (5.5” rim & 180 tire, not the 6.0” rim from the ‘96–’00 GSXR750), brake caliper/rotor, sprocket & etc.
Swingarm most likely should not have bracing above the swingarm, bracing underneath the swingarm would be fine if it happened to be there. This is because that could be a clearance problem for the dual shocks that need to mount vertically from the top of the swingarm up to the subframe near the seat of the bike. My initial thoughts for potential swingarms are either from a ‘97-’03 GSXR600 (’01-’03 is 20mm longer then the ‘97-’00), GSF Bandit 1200 (’96-’06) or GS1100E (’80-’83). Would a swingarm from a different brand work… like from the Kawasaki ZRX1200 for example? But then that would bring in the problem of ill-matching swingarm, wheel, axle, brake, sprocket & etc. At this time, I’d like to keep the GSXR wheels.
Undecided about the swingarm, whether if I prefer the modern chain adjusters, or are the older threaded adjusters out the back just fine & might even look better with the overall look of the bike? Possibly a modern sportbike swingarm would look too thick & not proportional?
The old clapped-out OEM shocks are not going to cut it either. It would probably be cheaper to find a set of used shocks from a modern dual-shock bike, then it would be to buy a new pair of aftermarket shocks from Works Performance or Ohlins for example. I would like modern shocks with adjustability for compression, rebound & preload. Another thought is that with the extra weight that the GS has over a modern sportbike… both the forks & the shocks might need to be re-valved for that extra weight.
Still dual shocks, or convert to a single shock? How would I weld on the linkage if I tried to switch to a single shock, is that even do-able? If I’m still using the dual-shocks, I’d need to weld on lower-shock mounts to both sides of the modern aluminum swingarm… the GS1100E might already have these on there though plus look more authentic with the rest of the bike… but I’m not sure I could use a 5.5” rear rim with that old of a swingarm?
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Footpegs & Controls – Custom mounts to retrofit modern OEM GSXR footpegs, shift & brake levers to the GS frame. I think I prefer the folding footpegs so if it tips over (or worse)… then if they fold up, it might be less likely to brake more valuable things (like the frame or footpeg-mount itself).
I would need to convert it to a shifter with a linkage like the modern GSXR, because of the new footpegs being located further back & up from stock… well also because the stock GS shift lever does not use a linkage, it just bolts directly to the shift shaft.
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Chain & Sprockets – A gold colored O-ring chain & “cooler-then-stock” looking sprockets. In my little research so far, the aluminum Renthal’s seem to look the best from what I have readily available.
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Countershaft Sprocket - I would most likely need to offset this to line up with the wider 5.5” rear rim. Will I run into problems with the chain rubbing on the side of the frame with this wide of a rear rim? I read somewhere about machining down the cush-drive in the rear rim to help bring the rear sprocket in a little, this would get the chain a little further away from the bike frame, as well as require less offset on the countershaft sprocket. What other options are out there for a solution to this?
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Battery – Consider relocating to a less conspicuous location… opening up the chassis & seeing through it more… giving it a little cleaner & more open look. Plus my battery box is rusted some.
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Wiring – Consider updating & improving the stock wiring. Try to hide it as much as I can, plus making it easy to work on things by possibly moving wiring more out of the way.
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Electronic Ignition - I will want to ditch the points ignition & install an electronic ignition. Dyna sells a conversion kit for the GS. Part# DS3-2 fits ‘77-’81 GS 750’s as well as 1000’s. Meaning that if I buy this now… it’ll still be the correct one for a 1000, if I even happen to swap motors & go big-bore
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Exhaust – It’ll need a sweet set of pipes. Consider both “high-mount” as well as a system exiting under the motor, GP-style. The GP-style under the motor, that would make it easier to avoid the dual shocks, finding a mount up near the passenger footpeg, as well as giving the rear wheel a more exposed & open look. But the “high-mount” is synonymous with road racers from the 90’s to close-to-current… which might go better with the overall look & completeness of the whole bike?
Either way, this sounds like a custom job… I wonder how much that’s going to costs? Vance&Hines sells a nice Megaphone system for the GS, maybe I could just use the header from that & have it cut-off & custom made behind the collector where it joins from 4 into 1? But since I’m not imagining a Megaphone style system… I’d also need to find an aftermarket silencer that is nice looking & sounding from a modern sportbike & have to bent & fit to the header.
A race system with spring-mounts, natural stainless or a high-tech ceramic-coating or something versus painted black… would be sweet as well.
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Motor – Some serious cleaning/de-greasing/polishing of the 750 motor with eventual motor mods or even a complete replacement with an air-cooled GS1000 motor. Possible mods could be; bored-over, cams, higher compression, head-work, rebuild bottom end, clutch rebuild & etc.
I feel that I would want a torquey motor, but of course some HP would be needed as well. The stock GS750 is supposed to make around 60-65HP… I’d like something with about 100HP, as well as plenty of torque down low (a modern 600 sportbike makes around 105 hp). It’s gotta be able to beat a stock Twin-Cam Harley, or whatever they are calling their “mainstream” V-Twin these days.
Maybe a little bit of a lumpy idle would be cool.
Would the entire motor, or parts of it, look better painted black, polished or left natural? Initially, I don’t know how much I’m going to want to keep polishing it over & over to keep that perfect polish though.
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Frame – Weld on additional bracing to strengthen the frame. I have seen a few web sites that talk & illustrate this.
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Instruments & Headlight Mounting – I would need to design a new mount for these since they currently mount to the skinny stock forks, and I am hoping to be mounting some thick-ass modern inverted forks. Would it be cooler to use the stock gauges or install some newer AutoMeter “style” gauges?
What about the speedometer cable? What year GSXR’s still used a speedo cable off of the front axle? Would I need to mount up a digital bicycle-style speedo (can they even be read at night)?
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Headlight – New “bright white” round lens assembly with halogen bulb. Initially I see this mounted in place of the current headlight housing… using the stock chrome trim that goes around the headlight, as well as hiding the wiring.
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Rear Tail Section – Kind of ugly the way it is, I know… I know… it’s original & that’s how they look back then. I would like to possibly consider some custom made unit that shows off the rear wheel a little better. Would I prefer a single or dual seat? What about putting a modern sportbike seat on it, but not their body work… just the seat pad & integrating that into the custom tail section? Again, not likely just taking a modern sportbike tail section & putting that on it… initially, I don’t feel that would look “correct” or proportional on the bike.
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Taillight – LEDs – either behind a “clear” lens or no lens? Well I don’t exactly see LED’s being used with the stock rear tail section… this might only fly with a custom “modded” rear tail section.
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Turn Signals – For sure something smaller then stock… but most likely they should still look relatively old, so they match the body of the bike… keeping everything in balance. A modern flush-mount would most likely look out of place with the rest of the bike. I really would want to keep things in balance, so no part stands out… even though I’m talking about some drastic customization… I still really envision the bike as from a quick glance, looking like it could have been factory. Maybe that is being un-realistic though?
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Paint – Later on, after all or most of the parts have been fitted, then a new paint job on the body, as well as frame, wheels, suspension & etc.
I’m thinking Black for the; frame, wheels & swingarm… maybe even front forks.
For body colors, I’m really thinking a Red, Black/Gray & White combo.
I’m a believer in that the paint doesn’t make the bike… it’s the mechanics of the bike that make the bike.
November 18th, 2007 at 5:32 am
Bill,
I am building a GS750 to race in the UK National Post Classic series, I am stuggling to find the sites you mention that illustrate where the bracing should go on the frame and also what the ease of changing the headstock angle is. can you advise any useful sites ? Any help would be greatly appreciated. I can ride ‘em, but swinging spanners is new !
November 18th, 2007 at 11:05 am
Iain,
Thanks for stopping by my site, I’ll hunt through my bookmarks & try to find some…
OK, this guy has a lot of knowledge on these bikes:
http://www.robwilton.com/kats.html
This guy’s done a little bit of it:
http://www.gsx1100.com/site4/articles/arnout’s_Kat.php
http://www.gsx1100.com/site4/articles/katana_project.php
http://www.gsx1100.com/site4/tips/frame_bracing.php
Here’s some more from somebody else, Look at the Phase 1 - 3 links:
http://www.prutser.info/home2.htm
There might be some good info in here, not sure though:
http://www.tonyfoale.com/
Follow this one through the 3 or so pages:
http://www.thegsresources.com/_forum/showthread.php?t=80503&highlight=katanakid
I think that is all that I know of, these should give you a good start, or at least some good resources.
Bill
July 13th, 2008 at 11:15 am
Glad to here of another mad man willing to rebuild the 7 & a half. I’ve already been down that road and the biggest thing is you have to develope it all yourself as like you. Try it dump it start agian. I searched high and low for info very little to be had as most of the modded bike were 1000’s(lots of similar or same parts but not everthing works on the 750). So here’s what I’ve done 520 chain conversion, JMC swinger, Yoshi/KYB shocks, maxton forks, GPZ front wheel with R1 discs and twin pot brakes, GSX rear 17″ wheel, custom 4-1 high level exhaust, braced frame and custom loom. Engine wise Dyna coils and ignition, flowed/ported & skimmed head, 1 mm over size valves, new pistons, honned barrels, billet race cams, 29mm smoothbores(on my 4th different set of carbs still not 100% correct yet) custom cam chain tensioner.
Realisticly the 750 make 55-60 stock I’ve dyno’d 3 and they all fell into this range, so anything over 60 is a good-un. The 1000cc makes about 70-75 stock so waould be a cheaper and easier option. If your looking for 100+ BHP from the 750 you’ll need all the above engine work and a little more. If you flowed the head and got a good setup for carbs-exhaust you’d be near that with the 1000.
As well as the sites you mention check out http://oldskoolsuzuki.info/ loads of helpful guys and Toad hole racing a guy who still races a GS750 in AHMA (or is it AMHA)
July 13th, 2008 at 1:38 pm
Thanks Brian,
That is some good info, something that I’ll keep for future knowledge. If you have skimmed my site any since I wrote this post, you probably have figured out I’m sort of struggling to just get the bike on the road, in its near stock condition. So while this post still holds true for the future, it is much down the road… as I’m just trying to get the bike on the road at this point, I just want to start riding it, then begin to slowly mod it as I see fit.
Again, thanks for the info & reading my site… I will be considering your input for sure.
Bill
December 24th, 2008 at 4:13 pm
Hi Brian,
I’m working on a 78′ GS750. I’ve already put on a 01 GSXR600 front end & brakes, 93′ modified sub frame, 98′ GSXR600 swingarm with the single shock, and designing custom rearsets. I’ve had to do a lot of modifying and custom machining. The bike probably wont be done for another year or so. Great info