1977 GS750B - my long awaited first bike!

[Chuck78]

yeah this was about 40 minutes before nightfall, I was planning on getting back onto 33 around Nelsonville at dusk so that deer and visibility around tight curves would be less of an issue. I don't think I will be doing any riding near dusk this time of year ever again! my knee is still hurting quite a bit and still very swollen and sensitive. Hopefully everything under the kneecap is going to be fine once the swelling goes down.

 

[Chuck78]

My screenprinting buddy is going to help me screenprint new gauge faces, as I was envisioning in the first page of this thread, based on the edited images of the scans of those GS400X gauges converted to 130mph from 110mph, and 10,000rpm redline and the addition of an oil pressure light on the speedo which was absent from the GS400X tach face indicator lights. The 1/8" or 1/4" smaller diameter individual chrome pod gauges with the brights, turn signal, and neutral lights built into the gauge faces are so much more classic looking than a big spaceship console hunk of plastic or even the larger dual pod gauges with the indicator light console as a separate piece in between the gauges. Apparently I needed to use a vector image file format to get rid of the pixelated style of images, so we're going to convert the image or redo the scans.

In the meantime, I was thinking of either getting some 14G aluminium stock and hand cutting some extra faces to paint and print on with plastisol ink, or have my machinist buddy laser cut or cnc cut me some thinner (stock) aluminum sheet to make several sets of these revised gauge faces since I will have the printing stuff set up.

I tore apart the GS400X gauges immediately to start this project, and they are still sitting in pieces. Now that I have a demolished stock GS750 speedo thanks to a deer, and my screenprinting friend is really busy for the next month, I scored a set of GS400B gauges (no indicator lamps in tach face) off of ebay in better shape than the GS400X guages I had, but still with some speckled and faded faces. I am going to throw these on my bike for the time being, and search for a few more pairs of these. I will plan to add all the indicator lamps in the form of radio shack LED's/lenses into the GS400B gauges to make them like the GS400X gauges plus the oil light in the speedo, and hope to find a few more sets of these smaller chrome or black pod gauges from the smaller 70's bikes (GS250 or GS400/425) so that I can make use of the extra faces we plan to print up. I can only use those models mentioned with 110mph speedos or else the speed won't be to scale with my image file (original incremental spacing).

 

[Chuck78]

Also tracking down a spare engine to do the 920cc conversion to thanks to another member on here.

Thanks to the local VJMC junkyard, I also have some front Honda turn signals (dual filament sockets so I can have front running lights for better visibility to cars) and new stems to match the rears on my bike and replace the OEM fronts after the deer collision. I also have some EMGO headlight brackets and an H4 halogen 6" lens and chrome bucket from an L model GS, which looks really really awesome! 55W H4 bulb as well, shown in picture next to an H4 halogen 7" setup like what I had. The chrome 6" setup looks really awesome, probably using that. I was at a loss for the assumingly wider projection area on the 7" light vs the assumingly brighter more focused spotlight beam on the 6" L model. The L model bucket is heavier, but worth it in looks, and I will be losing the big gauge console for some smaller gauges and losing the bigger headlight brackets as well. If I'm not happy with the beam projection on the 6" H4 setup, I may try for an aftermarket bucket. This was the sharpest looking of the used and new ones at the Rice Paddy, so I figured I'd give it a shot for $35. the 7" H5 marked lens that I had (looked identical to the left one with the black plastic bucket except the lens was flatter) was the brightest thing I have ever seen on a bike with a 55W bulb, nice side to side visibility for deer spotting on the sides of the road! Hoping the same bulb in the 6" reflector lens will do just as good of a job.

All of these parts are sitting on top of the seat foam you see below with a new padded vinyl upholstery cover that I have not yet stretched out & permanently attached. I think I may shave the seat foam down slightly shorter by 1/2" & smooth it out with some angle ginder action.

 

[Chuck78]

Also I've done a little work to restore the cracked and rusted original seat pan, and shaved down the foam to have a totally flat seat. I am tracking down an L model rear fender and taillight as well to bobb a little length off of, and deleting the trunk/tail for a more classic look, as well as welding some sheetmetal onto the rear of the seat pan to make the seat extend down to the fender, where the original only came down enough to not see a void below the height of trunk/tail section. I have new upholstery for it as well, and may even try and screenprint Suzuki GS750 on the rear of the seat, or maybe GS900 or 920 even... although GS750 is of much greater notoriety, and will keep it a bit of a sleeper to **** off the modern sport bike riders who wouldn't suspect this already really-fast-stock bike to be even more of a bullet! I love these old 1st gen GS550/750/1000's... So well built for their time, and so easy to mod out the intake/exhaust/jetting, brakes, suspension, and tire/rim choices....

 

[Chuck78]

Here's a little reminder of how to proceed riding in rural areas during deer mating season (called "rut" - in late fall). Deer fur jammed into the headlight bucket trim, and even into my spark plug wire to boot connection! Darnit I really loved how awesome of projection that 81/82 GS650 "H5" headlight had... Smashed to pieces, deer fur even back where the bulb was...

 

[Chuck78]

NEW 2ND BIKE - 77/78/79 GS750 pile of parts!

NEW 2ND BIKE - 77/78/79 GS750 pile of parts!

Well I acquired a second bottom end of a 1979 GS750N engine to start building a fresh 920cc engine out of, and then to get some good stator and ignition covers and a good set of GS750 cams, the seller basically threw in a seized engine to the deal for near scrap metal prices, and then further threw in the 78 GS750 frame that the seized engine was still bolted to that has been parked since 1985! The title was notarized & signed over but never transferred, but I've tracked down the titled original owner (several un-legit owners later) and he happens to live a few blocks from my mother-in-law, of all the luck!

Looks like after I get this massive house remodel finished in the next two months, I can now start welding in a few frame braces and repainting my new spare frame on the bench, and build up it's original gearbox/crankcase with my 69mm bored out to 72mm 850 cylinders and 920cc pistons, and a spare cylinder head (scrap engine's rings are rusted to the bores I suspect, valves are all crusty looking from the exhaust ports being open to the air). This is awesome news, because then I can basically have my bike together the whole time while restoring and bracing this 78 frame (matches my birth year and my 1st car - 78 Camaro, hence Chuck78 on Camaro forums). Then I can swap my forks, wheels, swingarm, brakes, etc (all the parts I already replaced or modified or upgraded) all over to the redone frame all at once! I also got the almost perfect gas tank as well that was originally on this 78 since the deer collision dented mine.

Then I will have my 77 frame and the engine in it to repaint, put new gaskets in, and maybe an 80 850 CV head with some GSXR Slingshot carbs for kicks! I can bolt all of my original 77 parts back to that with some upgraded brakes that I have here, and still build a barebones racer out of it with all of my spare parts!
The only major things I am missing would be good new tires and a 4-1 exhaust! Carb jets and o-rings, regulator rectifier, clutch lever, EMGO headlight brackets, battery delete capacitor for kickstarting assistance, front fender, and throttle grip control and left side light switch control. All I'd need now to build a second GS750 from spares... wow. Awesome! My CB750 buddy says "cool, let's build a track bike and race it at all the vintage events!" Well, I think my main ride is practically suited for that already, but I dont want to wreck it OR myself! All in all, good news. No more GS400/425 project plans I guess!

 

[T8erbug]

Well I acquired a second bottom end of a 1979 GS750N engine to start building a fresh 920cc engine out of, and then to get some good stator and ignition covers and a good set of GS750 cams, the seller basically threw in a seized engine to the deal for near scrap metal prices, and then further threw in the 78 GS750 frame that the seized engine was still bolted to that has been parked since 1985! The title was notarized & signed over but never transferred, but I've tracked down the titled original owner (several un-legit owners later) and he happens to live a few blocks from my mother-in-law, of all the luck!

Looks like after I get this massive house remodel finished in the next two months, I can now start welding in a few frame braces and repainting my new spare frame on the bench, and build up it's original gearbox/crankcase with my 69mm bored out to 72mm 850 cylinders and 920cc pistons, and a spare cylinder head (scrap engine's rings are rusted to the bores I suspect, valves are all crusty looking from the exhaust ports being open to the air). This is awesome news, because then I can basically have my bike together the whole time while restoring and bracing this 78 frame (matches my birth year and my 1st car - 78 Camaro, hence Chuck78 on Camaro forums). Then I can swap my forks, wheels, swingarm, brakes, etc (all the parts I already replaced or modified or upgraded) all over to the redone frame all at once! I also got the almost perfect gas tank as well that was originally on this 78 since the deer collision dented mine.

Then I will have my 77 frame and the engine in it to repaint, put new gaskets in, and maybe an 80 850 CV head with some GSXR Slingshot carbs for kicks! I can bolt all of my original 77 parts back to that with some upgraded brakes that I have here, and still build a barebones racer out of it with all of my spare parts!
The only major things I am missing would be good new tires and a 4-1 exhaust! Carb jets and o-rings, regulator rectifier, clutch lever, EMGO headlight brackets, battery delete capacitor for kickstarting assistance, front fender, and throttle grip control and left side light switch control. All I'd need now to build a second GS750 from spares... wow. Awesome! My CB750 buddy says "cool, let's build a track bike and race it at all the vintage events!" Well, I think my main ride is practically suited for that already, but I dont want to wreck it OR myself! All in all, good news. No more GS400/425 project plans I guess!

I'm actually thinking about building a track-only bike too. It will be sweet if I can get another GS750 because then I can take from one and add to the other if needs be and hopefully in the end they can both benefit from each other.

 

[Chuck78]

When I told my dad that I had acquired enough parts to build almost an entire spare GS750, and he said "GREAT, I CAN'T WAIT TO TELL YOUR MOTHER YOU FINALLY BUILT A MOTORCYCLE FOR ME!" He had some old Suzuki GT 2-strokes in the 70's and 80's, as well as being a pit mechanic on a motocross team, I think it was a Penton racing team.
I'll build the #1 spare engine with my GS850 pistons and bored out 750 cylinders that I'm running, GS850 CV head, and GSX-600F Katana Slingshot carbs, and GS750 cams. It will get full OSS frame bracing - the critical ones at the mid section, GSXR rearsets, and the 310mm single disc, and be a kickstart only bike. Might even play around with welding some bracing onto the swingarm if I don;t find a deal on a GS1100E swingarm. Chopped springs and stock shocks until I find something budget and good to throw on the rear.

My plan of action first is to tear into the seized '78 engine to rebuild the bottom and use the 850 cylinders/920pistons and a spare GS750 head. Get that built up, and then weld bracing in on the '78 frame, decide what tabs etc will get shaved off that, and drcide if I want GSXR rearsets on both. Then repaint that frame with appliance epoxy, let it cure for a week, and install the 920cc engine innit with reworked vm26's, and then swap all the parts off of the '77 onto it. Then I can redo the '77 frame, freshen up the engine, and basically reinstall all the original parts that I swapped in favor of high performance wheels/brakes/suspension/swingarm/etc.so that frame will end up basically the way it was when I first started riding it, but with cv carbs and a monster single disc brake, and 78+ rear brakes since the monster stocker was just too much. Shinko 230 tires on stock spokes.

 

[Chuck78]

http://service.foxracingshox.com/powersports/Content/Resources/pdf/Vintage/FOX FACTORY SHOXforMX.pdf

I also tracked down on a factory service manual for the Fox Factory Shox. This one is geared more towards the MX versions (long travel, taller lengths, mx springs, external remote reservoirs), but the valving and rebuild procedures are the same. It just doesnt list any springs rates or part numbers that work for the road version of the shock that we are interested in.

 

[Chuck78]

Any1 have vintage Fox Factory Shox setup tips or background info? spring rates?

Any1 have vintage Fox Factory Shox setup tips or background info? spring rates?

Now on to the latest for me. I am at a halt now for spending on the GS, as engine and frame work will start in April most likely. I'll get the GS back on the road with the lighting and cosmetic repairs, and get the custom gauges finished (need to print custom stock-styled 130mph faces for the GS400 gauges still, and get the wiring rearranged.

I was considering dropping $500 on some really awesome Hagon Nitro's or YSS Z-362 shocks, but ended up with some real awesome vintage rebuildable Fox Factory Shox. Pretty high tech shocks for a set of 1980's top of the line Vintage racing shocks, they have an external piggyback reservoir with a bladder separating the nitrogen charge from the shock oil and quite a complex valving system that is FULLY ADJUSTABLE for compression and rebound. Fully rebuildable and parts are still available - http://ltthor.home.comcast.net/~ltthor/FFS.html.

They are one of the top 2 or 3 most sought after vintage aftermarket superbike (and MX) shocks, and sell for $600-$700 restored. These came to me in a pretty sad and worn out state, but after a full seal kit, repainting the springs and polishing the bodies, and replacing a pitted shaft, they will be very legit shocks. Pros - awesome looking piggyback setup, great dampening. Cons - not externally adjustable, have to tear them down to change valving shim spring stack setup and/or swap jets. preload is also easily adjustable.

Factory Service Manual -
http://service.foxracingshox.com/powersports/Content/Resources/pdf/Vintage/FOX FACTORY SHOXforMX.pdf

Also thinking of replacing the eye bushings with spherical stainless steel teflon lined eye bearings:

 

[Chuck78]

Fox Factory Shox spring rates?????

Fox Factory Shox spring rates?????

I checked out the MX manual for the Fox Factory Shox, and here is what I have gotten from it. Installed with the preload in the middle somewhere, my springs measure 6-1/2" (long red progressive spring with yellow paint dot) and 2-3/16" long (short blue spring with orange paint dot).

According to the manual, if it's spring codes are still applicable for the 13.25" long road version of the shock, I probably have the 7-1/2" and 2-3/4" springs that this manual says fit the 13.75" long shocks (haven't found my calipers yet to check diameters):

red 7-1/2" spring w/yellow dot
.295" wire diameter
p/n 96-2570
rate - medium-soft
(the other .295" wire w/pink paint dot spring lists 146 lbs/in, so I assume the chart reflects the med-soft as a progressive rate that is softer than that at first and stiffer when the tight spaced coils bottom out)

red 7-1/2" spring w/yellow dot
.306" wire diameter
p/n 96-1515
rate 166 lbs/in

2-3/4" long blue spring w/orange dot:
.263 wire diameter
rate - medium
96-2180

So it seems as if these springs will not be too harsh for me, and I probably lucked out with the spring rates and that the long red is a progressive and not a straight rate. I was going to go with around 110 lbs/in "averaged rate" progressive rear springs in a new shock. Adding the unlisted lbs/in of the short blue spring will decrease the rate, but the tight spaced coils bottoming out will increase the rate a lot upon hard cornering compression. I have no clue how to add the two rates/wire diameters together even using a spring rate calculator, but I think they will be just about right for my weight and lightened bike. Whaddya think? I'm very thankful that the springs are right in the neighborhood of where I wanted, so that I can keep the trademark originals on it!

Now I just have to decide what kind of valving I need after I tear it apart to see how it's set up as-is.

 

[Chuck78]

Well, today I dropped $50 on two of those s.s. teflon lined spherical eye bearings on ebay, and I also figured out spring rates. Salty Monk on here is 10lbs heavier than me and has a slightly heavier bike, and he runs a 43 lb/in fork spring and progressive rear springs in the 95/140 lbs-in intial/final spring rate. He says thats a sporty ride but still not harsh.

My bike is a bit lighter, and will be shedding more weight down to 480 lbs this coming season, and I am 10+ lbs lighter.
I just spent a long time figuring out how to calculate the rates of a progressive spring, AND the rates of two different springs stacked in one shock, talk about confusion in the late night hours!


Fox Factory Shox orange/yellow-progressive code springs:
93 lbs/in initial spring rate
117 lbs/in after 2.7" suspension travel
131 lbs/in after 3" suspension travel.
Fork springs (modded stockers):
46 lbs/in (removed the short tight wound spring in favor of an aluminum tube spacer).

Not too bad! I was planning on a 110 lbs/in straight rate rear, so this fits the bill pretty well but a bit on the soft side (maybe I can make up for that a bit with more preload to get it to arrive at the 117 lbs/in a bit sooner?) Awesome! Also discovered that the Hagon Nitro doesn't come in eye to clevis, so the 2810 is the best option for Hagons on a GS... the Nitro AND the YSS Z series are still emulsion shocks, and the YSS G series are $699 for the piggyback model that seperates the oil from the gas. So it seems as if I got the best bang for the buck even if I spend around $450-500 rebuilding the Fox and messing with the jet and the shim stack to change the dampening. No wonder people referred to them as the best vintage shock ever made. They were probably the first piggyback DeCarbon style shock available for these bikes

 

[Chuck78]

springtime is here!

springtime is here!

I finally got the bike mostly back together with the cosmetic upgrades that the deer collision made me do sooner rather than later. Carbs need some work and swapping of needle jets, jet needles, and maybe pilots, but I went out for my first ride of the year today on the bike.

EMGO headlight brackets (required lots of re-bending and some drilling) fitted to the GS1000L chrome headlight bucket, GS400 gauges, CB400 dual filament turn signals, etc... I just have to wire in LED's for my indicator lights now! Got a used Vance and Hines pipe also, not installed yet. I forgot how much of a bark that homemade baffle I built for the MAC muffler has, love those GS750 cams and an unrestricted unpacked baffle!

Tore apart the Fox Shox today also in order to measure for a replacement shaft, since one has rust pitting on the chrome. Can't wait to ride it with these things after a rebuild and ditching the TOTAL CRAP BikeMaster fork seals that leaked ever since installation 11 months ago...

 

[Chuck78]

I am REALLY happy with the way the front end looks now with the GS400 gauges especially. I like the look of the new turn signals and narrower stems much better as well, and the EMGO headlight brackets... I always had hoped it'd look like this. I also now have 1157 dual filament bulb sockets up front thanks to the Honda turn signals, so I have running lights for more visibility. I had to drill out the EMGO brackets and ditch the mounting screws and use the turn signal stem attachment stud as the new headlight clamp bracket bolt in order to keep things looking clean and give the turn signals a place to mount. This in turn put the turn signals a bit lower than stock, which along with the narrowest stems I could find at the junkyard, give it a nicer cleaner look.

 

[Chuck78]

I've got parts in the mail for the Fox Factory Shox, got the springs curing for 7 days after painting satin black with VHT Epoxy paint, got the aluminum parts buffed to a mirror polish, & surprisingly the zinc(?) plated bodies polished like chrome, and I sanded the rubbed-bare rusted steel parts of the main cylinder & they buffed out almost like chrome as well! The plating looked too good to paint vht black or bake-on brake caliper silver, so I got some Brownell's gun finish clear epoxy paint to seal the steel main cylinders and preserve the polished look on the plating and polished bare steel. I was going to do black main body cylinders & clevises, but this polish surprised me so I thought I'd run them like that.

 

[Chuck78]

Still waiting on shock shafts for the Fox Shox from Thor/Evolution Suspension, who hasn't responded to my email for almost a month!!! Really dying to get these things on the bike...

In the meantime, my battery totally died, as in not even enough voltage stored to assist my Dyna-S in working at all... Electric start hasn't had enough battery this whole season to crank, but the ignition worked at least. This led me to research the kickstart battery delete option that I have been wanting.

Apparently it takes at least a 40,000uF capacitor that is rated for at least 30 volts (upwards of 75 or 100 is better bet in my opinion) to smooth out the low spots in the pulsed DC output of the regulator-rectifier enough to start a points ignition bike easily (as well as lessen the seriously flickering lights you have if you get rid of the battery). The Dyna-S on the other hand requires much more electricity to produce a spark, and so may or may not work well with a large capacitor. I am thinking the later 1980+ suzuki stators and rotors with more poles (11 vs 7 I think??) may work better for this application, less large split second drops in the voltage, but the Dyna is definitely going to require more power, and therefore I researched the tiny battery option...

I looked into Shorai, Ballistic (Alien Motion is the same thing basically, rebranded), and Antigravity. Antigravity was the most highly spoken of amongst the caferacer/dotheton forums, Ballistic was #2. They use Lithium-Iron-Phosphate battery technology, which gives you a battery that is double the cost but 1/6th the weight and 1/3 the size... But these batteries will get fried by old regulator-rectifiers that often let out voltage spikes above 14.6 (an upgrade to a Compufire or SH-775 is a great idea regardless), and also will be damaged if their charge gets drained below 9.5 volts...

Anyhow, to have a headlight if the bike dies or I am camping with it and need some quick light, and to make the Dyna-S happier than a cap, I shelled out $107 for the smallest Antigravity (4 cell) battery, and I am very pleased! 16oz vs 6lbs3oz in the smaller lead acid battery I had!

I don't want to push it with this battery trying to crank the new 920cc high compression engine that I am building, so I am just yanking the starter, idler gear, and starter clutch gear to save weight.

I looked into Lou's aka LoudGPZ/LoudHVX GM Cavalier HEI module based ignition using some 80-81 electronic pickups, and it uses about 1/5th the voltage of the Dyna, and auto parts stores and radio shacks are everywhere across the US in case of an ignition failure, so I am really thinking I may swap the Dyna out eventually in favor of the DIY HEI circuit, which also would start much easier with a battery delete capacitor than the Dyna... Points are still the best option for a battery delete kickstart bike, require way less voltage to fire, but more maintenance.

As I mentioned above, I have also ordered all new gaskets, o-rings, and seals for my bike, and I will be tearing down a spare parts engine to swap the 850 cylinders and a fresh 750 head with a high performance radius (inner) cut valve job. Finally I get to use those MTC 72mm pistons I picked up a few years ago!

Also desperately needing to trash the BikeMaster fork seals and swap some AllBalls seals in place, and upgrade to a needle bearing setup for the steering while it's apart. Been putting those off for some time. Stay tuned for engine rebuild details!

 

[Chuck78]

Look what I picked up yesterday! Performance valve job with radius cut transitions into the 45 degree valve seat, valves lapped and back cut 30 degrees to improve low lift flow quite a bit, head decked slightly to true up surface and bump compression slightly, GS850 cylinders bored out 3mm over, which is 7mm overbore compared to a stock GS750! GS650 cylinders in the background were inspected and given a clean bill of health for a hone-n-go ring job on the GS550 engine upgrade project as well. Woohoo!

Now I'm waiting on 2 orders of Suzuki engine parts and still waiting on the Fox Factory Shox rebuild parts, with no correspondence from the sole proprietor of Evolution Suspension for one month... Still waiting on the repro shafts from the forge or chrome platers probably, but some correspondence would be nice.

If I'm real lucky, I may get this together to test ride to the Vintage Grand Prix at Mid Ohio Sports Car Course (NICE road race course) last weekend of June. If not, I will be breaking in this engine going to AMA Vintage Motorcycle Days at the same race track. HUGE swap meet and weekend of vintage racing and hundreds of awesome spectator's bikes to appease the eyes!

 

[Chuck78]

STILL waiting to get some correspondence from Thor about the Fox Factory Shox rebuild parts... I believe he was waiting on the shafts to get back from the forge and then to the chrome platers... No replies at all from him.

I got the polished steel zinc plated cylinders polished very well and then degreased 10 times with acetone, then clearcoated with Brownell's firearm epoxy paint. WOW do these things look good, I am VERY HAPPY with that at least! Now if I could only ever get the darn parts to rebuild them with! If it weren't for the shafts and shaft seals, I'd be good to go, the o rings are all pretty soft and supple still.

That's obviously just a mockup with the shorter spring absent, as I just wanted to see how the colors looked together. Very pleased.

 

[jbird7262]

yes they are designed for VM26 carbs as found on the GS750/850/1000 and KZ900/1000, possibly KZ750, all of the late 70's before cv's were the norm. the carbs on all those bikes are interchangeable basically or at least have the same spacing just not the same jetting etc

So will those air filters also fit 1980 GS750E, running a uni set up with V/H 4 to1

 

[Chuck78]

No, they only fit the vm26/28/29 carbs. Check the k&n filters for a 1990 katana 600, they may work. RU-2422 or something. There is a long list of k&n universal filters, look it up & check dimensions and you should be able to match something up.