1977 GS750B - my long awaited first bike!

[Chuck78]

FINALLY, I don't have to pay Woody's $514 to have them lace up a used GS750 hub with stainless steel spokes and nipples and a new DID 3.50x18 aluminum rim!!!!!
http://http://www.ebay.com/itm/150960689420

Been searching ebay for a while. Missed out on a $120 and $170 3.50x18 36 spoke rim, but finally found a deal! GS1000/1100 rear wheel off of a GS1150 drag bike with GS1100 engine. It's the correct 36 spokes and Suzuki bolt pattern on the rotor, must be an older GS1000 wheel? 1100's and 1150's were almost all mag wheels as far as I've seen.

I will probably get a new Excel 2.50"x18" front rim next, give my wife my my nice clean 19" front wheel, ditch her rusted GS550 spokes and rim to relace her front hub into my new alloy rim with some stainless spokes. In the future, I'll relace this new used rear with stainless spokes and polish the hub on a buffing wheel while I'm at it.

 

[Chuck78]

Also purchased the upholstery to re-do my seat, $30-ish on ebay with a layer of foam padding sewn into the vinyl already with lateral pleats going across where it's sewn. I will be shaving down my seat foam flat (ditching the rear high rise portion) by reshaping it with a 4" angle grinder. I may get a bicycle gel seat cover, and cut a recess into the foam to insert it in the driver position. rear of seat will be minimal. I had considered going solo seat and getting rid of the passenger footpegs and exhaust mounts completely and leaving the fender exposed with some bracing to support a set of saddlebags, as well as ditch the GS trunk. I will swap my battery for one half the size, lower the battery box as close to the swingarm as I can, and then build an aluminum box where the battery was as a storage compartment under the seat.
I had even contemplated removing the battery, starter, and starter gears to save weight, but I would have to add a big capacitor to where the battery terminals hooked up to act as a cushion to the charging system, so I figured I'd just use a smaller battery even without a starter, to give the ignition a little more firepower when kickstarting cold.

 

[Chuck78]

Other than just wanting alloy rims on my spoked wheels, I wanted to upgrade rims so that I can run wider than a 110 or 120 rear tire safely without poor handling from the tire squeezing into a narrow rim and flexing massively in every turn.

From reading GSR members' feedback and the love for the Avon AM26's and bargain priced Shinko 230 Tour Masters (formerly Yokohama treads and compounds), I have so far narrowed it down to:

Shinko SR741 rear
$77 140/70/18 (5.4" wide and 26" diam)

Shinko 230 Tour Master fronts
$81 120/90/18 (4.69" wide 26.5" diam recommended 2.75" rim but same size in Avon says 2.5" or 3" rim)
$67 110/90/18 (4.29" wide 25.79" diam recommended 2.5" rim)(much smaller than the same size in Avon's)

or the slightly more expensive Avon's with really great customer support, wide variety of sizes available:
Avon AM26 Road Rider rears:
$147 140/70/18 5.6" wide 26.2" diam (3.5-4.5" rim, 3.75 is best)(closest to the stock 26.4" diameter)
$115 150/70/18 6.1" wide 25.9" diam (3.5-4.5" rim, 4.25 is best - very close to tire, 150+ I'd say need offset sprockets)

Avon AM26 Road Rider front:
$109 110/90/18 4.6" wide 26.1" diam (closest to stock 26.1" for speedo accuracy)

These tires are all V-rated for speeds up to 149mph / 240kmh. The Shinko's are a great bargain, although I have not read of anyone here running the SR741, but the highly regarded 230 Tourmasters were not available in the rear size I wanted.
The Avon's are a very reputable brand and the Roadriders are a very appraised tire, and I may go with them if I have the extra cash. They also run a bit wider, so I will have more tread contact on the road. The rear tread seems to have a nicer radius on it for turning in quickly as well. But I will drop $100 more on them approximately.

I am really trying to shoot for a bike that holds the corners as well as a lot of modern sport bikes, has plenty enough modern braking technology to slow it down in a hurry (and save weight on the Ninja brakes vs the original Suzuki factory duals), and handles the bumps and twisties really well.

 

[Chuck78]

Now I need to get some Hagon 2810 ($299) or Ikon ($379 but rebuildable) adjustable dampening rear shocks 13" eye to clevis. I may save this for last since it is an easy bolt-on.
Before i do the dual disc upgrade, I will be putting some Sonic or Progressive brand springs into the forks and rebuilding them with new seals and bushings.

I had considered going with some RaceTech cartridge Emulators for $200, but I am going to hold off for now I think.

Also saving up for a VM26 carb o-ring kit, new gaskets and needle and seats, and appropriate main jets and jet needles according to some very well researched help from 49er. Those K&N RC2222 dual oval filters will eventually make it on here, and I will be removing the MAC 4-1 exhaust and de-rusting it, chopping it and bringing it about 3/4" closer to the bike height-wise, and wrapping it with black header insulation wrap to keep the engine seeing fresh cool air as much as possible to keep it running cooler with the higher compression pistons. Homemade baffle and MAC muffler shell will probably remain unless I find a deal on a V&H setup.

I was also tipped off that a GS1100 2 valve replacement head gasket has the 73mm bore that I need to work with my 72mm pistons, and it is a Multi-Layer Steel construction, the best and most bulletproof of head gaskets! (Suzuki # 11141-49410)
Getting a GS850 base gasket, and freshening up the rest of the engine with new gaskets and seals, and a GS650 neutral detent spring to help me get into neutral better.

 

[Chuck78]

Also got a nice GS650G top end for Reda's bike, cylinder jugs, pistons, head, cams, etc. Looking for some 1987+ GSXR600 BST33SS flatslide "slingshot" cv carbs or maybe the BS32's from the GS650 at the junkyard. Just got that rear wheel for mine, so I can donate my rear disc wheel to hers and use the GS1100 rear discs that came with the GS1100 swingarm to convert her drum brake rear (poor stopping power) to a GS1100 disc!
Also got a CBR1100 Blackbird 310mm diameter 22mm offset 78mm PCD front rotor for her bike and a single Tokico (Kawasaki Ninja) twinpot caliper to upgrade hers! The single disc bikes had higher caliper mounts, and Suzuki_Don has sucessfully fitted a 310 rotor on with one of Salty's brackets to a single disc fork. Gotta have lots of stopping power for my the love of my life, especially since I will be hot rodding her engine to put out around 80+hp! That bike is going to be a real screamer, one of the best GS550's you will find

 

[T8erbug]

I have been creeping on a lot of your posts lately because it seems we have some of the same ideas going on. It also seems we do more research and part buying than actual building and riding! I hope things get rolling soon on your build because I'm excited to see those parts come together to make a complete bike. Let me know when you get that new aluminum wheel laced up because I'd love to see it. I have a 79' GS750 with a GS1100 swingarm I have yet to install due to my hesitance to drill out the frame.. I'd rather come up with a sleeve of some sort to make the conversion. Also I have bought 78' GS750 wire wheels because I wanted wire wheels with dual front brakes. I want to make them wider (at least the rear). I just finished machining hub spacers in the front to fit GSXR bearings and Triumph Daytona 955 320MM rotors. Let's stay in touch as our builds progress because I think we can probably help each other out. Keep up the good work

 

[Chuck78]

Getting some late winter and early spring mods rolling out finally, after accomplishing some decent progress on the house remodel. We are planning a mid-may White Water Rafting trip and 6 day motorcycle trip in the West Virginia and Virginia twisties and mountain ranges, so my wider tire/rim upgrades and dual disc front brakes became an urgent priority!


I'm a little more ambitious and a lot more broke than most people (due to massive 1892 Victorian home remodel that us bleeding me dry), but I got some Kawasaki Ninja/GS500 calipers and Honda CBR900 rotors and some extra scrapped caliper brackets from the junkyard, and am making my own twinpot mod setup with no need for caliper adapter brackets. I was trying for some CBR900 310mm rotors wwith 22mm offset, or some CB600F rotors in the few years they also had 23mm offsets, but those were too hard to find without paying $220 for a new Chinese set (no used ones in the 296 CB600F versions). I'll be making up some rotor spacers from aluminium with a top hat type centering flange to make up the difference from the 56mm hub to the 62mm rotor opening to keep them perfectly centered.

Still have to chop up a second bracket and file-fit and notch it to weld, this week I hope! Then I'll be using more parts of the chopped brackets to use my wife's single disc GS550 fork to fit a 310mm CBR900RR 22mm offset rotor on hers with a GS500 left side single front disc caliper (same as the Ninja's). The 310mm rotor on the single disc left fork leg requires a bit more distance to swing the bracket out, a little more fab work but still easily do-able for those good at welding and fabrication

 

[Chuck78]

GS400X gauge pods in favor of the giant plastic hunk of a dash console

GS400X gauge pods in favor of the giant plastic hunk of a dash console

Also got these awesome GS400X individual gauge pods in somewhat decrepit shape from a parts bike at Rice Paddy Motorcycles here in Columbus (my local heroes for used VJMC parts!), cleaned up the pitted chrome to almost respectable condition, may sand and clearcoat or just sand and paint black if the remnants of the pitting bother me too much. The faces were useable but faded with some oxidation bubbles making the paint rough in spots. I disassembled them and scanned the faces, now making my own faces converting to 130mph from 110 and adding an oil indicator light on the speedo if I can cram it in under the tripodometer drum!

 

[Chuck78]

Unlike most people who want wider tires and just cram too large of a tire on for what the stock rim width can handle (pinching the tire and ruining their handling), I picked out new aluminium rims in the best recommended width needed from the tire manufacturers to run the tire combinations I wanted. 140/70/18 rear and 110/90/18 front. Close in diameter to the stock 110/90/18 rear and 90/90/19 front. I could fit a 130-150 rear on and 100-120 front with these rim sizes (2.50&3.50), but staying right in the middle for optimal tire profile curvature as the tire manufacturers have designed them for. Also, swapping to aluminium rims from the stock chromed steel to drop enough weight to compensate for the bigger tires adding weight.

I picked up a nice used DID WM4 2.50x18 flangeless rim for the front, $50 used from a mid 80's Yamaha TT600. It was drilled for a large diameter rear hub, so I just shipped it off to Woody's Wheel Works in Colorado to re-drill the spoke angles for a smaller diameter (front GS) hub. This requires moving the spoke hole on the dimple, so to keep the lower edge of the hole and change the angle, you have to drill offset on the original hole and oversize it from the standard .281"o.d. nipple up to .320" o.d. spoke nipple size to re-center the hole and give it a less steep angle. The rims are much thicker than bicycle rims that I am accustomed to lacing, therefore the nipple can't just float around at whatever spoke angle is needed based on the hub diameter and the lacing pattern (most are 2-cross on motorcycle wheels).

This was the best match I could find to the DID WM6 3.50x18 rear flanged drag bike rim I found for $150 laced into a GS1000 hub. Zach at http://www.woodyswheelworks.com is AWESOME, and is doing the work for me and custom making double butted (dual gauge) spokes to save weight (and make up for the larger nipples needed for redrilling a used rim to fit), 8 gauge at the hub and 10 gauge after the bend from the hub all the way to the nipple. I saved $100 having them redrill the rim after paying them $30 plus $50 for the rim plus a few bucks shipping both ways. $20 for a used hub shell.

That's one of my CBR900RR Fireblade rotors in the background, in the harder to find 78mm PCD. Machining some aluminium spacers to locate the rotor centered on the hub and spaced 5mm out to mate to the Tokico twin piston calipers from Kawasaki Ninja's 1998-2010-ish.

Also picked up this late 80's or early 90's GSX1100F (Katana?) front right rotor as a replacement for my heavier stock rear rotor. May upgrade to a GS1150 caliper if the pads are not as tall as the original rear brake's pads.

 

[Go Mifune]

Good stuff chuck. I like your resourcefulness and ingenuity man.

 

[Chuck78]

I had an hour tonight to finish what I started on the left bracket the other night, and here it is, looking like it was intended for this bike from the factory! I spent a good amount of time delicately grinding and filing the weld down and making sure the two fork mounting locations were flat and true. Two more to go (one for the 310mm single disc on the GS550)

 

[Chuck78]

Cleaned it up some, bevelled all the edges for better paint adhesion and shaving a few grams, ground off the raised thread support areas on the backside of the unused threaded holes and drilled out the unused threads for a cleaner look, as well as adding another hole in the center to break up the space uniformly and shave more weight

 

[Chuck78]

progress!

progress!

Well my buddy and I laced up our 2.50 rims on to our OEM hubs, tensioned & trued our eBay score former drag race bike rear wheels with 3.50 rims & oem hubs, and muscled on the Shinko SR 741 and 230 tourmaster tires diy! I painted my modified twin pot caliper brackets, my machinist buddy got my top hat shaped rotor adapters for the CBR 900 RR Fireblade rotors finished and the rotors are installed along with a 1990 GSX1150 front rotor as my rear rotor. CANNOT WAIT TO RIDE THIS THING!!!!

 

[Chuck78]

I got a Tarozzi Fork Brace as an early birthday present, as well as a gold 530 Hayabusa grade RK O-Ring chain, so I can install my GS1100E alloy swingarm as soon as I get some 530 sprockets! The Wife told me to order whatever shocks I wanted on her bank card because she didn't understand all the answers I gave her to the questions from Hagon/DaveQuinnMC. Dave Quinn Motorcycles told her "are you sure you want the adjustable Hagon 2810? That's a lot of money for a shock that isn't rebuildable. Adjustable dampening is harder to find in the $200-400 price range! So I looked into Works Performance and Ikon Shocks. The Ikon offering (7610?) is rebuildable and offers adjustable rebound dampening settings, whereas the Hagon 2810 offers one more click of dampening adjustment and is $309 vs $380(?) but is not rebuildable.

Also did the quick turn throttle mod I read in a recent thread here using a 7mm or so wide section of SCH40 PVC pipe stretched/snapped into place on throttle tube/grip. I vee'd mine out in a progressive ramp shape so it was still close to stock twist ratio off idle, but by 40% throttle, it is a very rapid twist action. This will also help with 65mph cruising in relation to wrist twisting effort, but still give you really quick wide open throttle when you want it!

 

[Chuck78]

Another score was a MAC GS750 4 into 1 header at the junkyard today for dirt cheap out of one of their bargain bins outside in the yard. a few rust spots, but my "non- 77 GS750" MAC that I just torched and bent to fit better - it is 90% rust 10% flaking off paint, and has two dents on the bottom, and was off a taller engine like 80+ GS750 or any GS1000/1100. This one looked the same but the muffler exit is at a better angle for my bike, and it is much cleaner and 95% good paint 5% rust and NO DENTS TO FIX!!!! Muffler will be tucked in under footpeg/exhaust mount frame instead of protruding out the side a lot and collector and muffler hanging WAAAAYYYYY TOO LOW like the non-fitting one fit to my bike

 

[Chuck78]

progress!

progress!

Crunch time for our West Virginia road trip! Took me forever to tear down and meticulously clean the Kawasaki Ninja calipers that had been on the shelf in the junkyard parts bins for years. so much crud on both sides of the outer seals, pistons stuck from dirt and varnish, the whole entire seal grooves lined with glued on dried up brake fluid varnish crap... dental pick, can of silicone lube, toothbrush, brass wire brush, and lots of brake cleaner. 3+ hours later:

Got the GS750 primary springs swapped out of the 750 single disc forks and into the dual disc GS650 forks, got the damper rods drilled and chamfered/deburred (another VERY TIME CONSUMING VENTURE, filing out all the burrs on the internal side of the holes for an hour after 15 minutes of marking and drilling), MikesXS Cartridge Emulators installed at 2-1/4 turns compression dampening preload, Lucas 15W fork oil installed.

 

[Chuck78]

That's really all there is, two main orifices at the bottom of the damper rod for compression and rebound both! If tearing apart your forks, the "DU" rings are the bushings between the uppers and lowers, one under the fork seal tightly fit into the lowers, and one snapped around a recess on the bottoms of the uppers. There's a teflon/nylon seal on the damper rod also. Mine were all in top shape, I was very surprised.

I got mine apart before reading the service manual, turns out I was real lucky. Leave spring in, and use an impact wrench with an allen extension to remove the damper rods to minimize the chances of the damper rod spinning once broken loose, which would require the special Suzuki tool insert on ratchet extensions to hold the damper rod in place while unthreading. I took mine out with a swift crank on the allen wrench with no springs in, and it came right out after the sound of loctite breaking loose.

Reinstalling, it said use some sort of Suzuki bonding agent on the first two threads and blue loctite on the rest of the damper rod allen bolts. I used Select Unyte plumber's pipe joint dope (rated for natural gas, diesel, gas, etc) on the first two threads, as it seemed this was to seal it from any seepage past the copper crush washers and bolt threads.

The copper colored piece is the upper du ring that presses tightly into the tops of the lowers just under the fork seals. the grey piece under it is the lower DU ring with the teflon coated side exposed. the copper piece and the fork seal and the washer just fell to the bottom, they slide around on the uppers. the grey DU ring is snapped into a groove and the anti-friction side is facing out. there are two auxiliary holes under the top out spring on the damper rod, but the two main dampening holes are near the bottom where the damper rod sits into an "oil lock" - an aluminium socket shaped piece that the damper rod seats into.

 

[Chuck78]

Bottom end of the damper rod, mods to drill out orifices to freely flow oil to allow the emulator to do the dampening. measure up 10mm and drill two opposing holes 90 degrees out from the original holes, then 10mm more on center and drill two more holes 10mm diameter 90 degrees more out, so they are in line with the original holes. All of them get drilled to 10mm (originals are 8mm) and chamfered (beveled) and meticulously deburred with something like a tiny chainsaw sharpening file or an attachment for a dremel. the inside is very tough to deburr. I chamferred the holes in the drill press with a much larger bit to give them a nice countersunk taper, and then started deburring for an hour.

The oil lock is the aluminium piece in the middle of the photo in the last post, although it is sitting next to the opposite end of the damper rod (top out spring and nylon seal end - the top/emulator side) that inserts into it. The tapered end of the damper rod with the 8mm orifices seats into the oil lock at the bottom of the fork.

Also, when disassembling, the 80+ models upper DU ring must be slide hammered out using the fork legs themselves as a slide hammer. compress and then WHAM! slide out rapidly 2 or three times until the ring pops out.

I had a 36mm i.d. piece of cromoly tubing laying around luckily, which was perfect to tap the DU rings and fork seals back in place. Make sure you have something lined up for this task. 38mm for the bigger bikes.

 

[Chuck78]

EMULATORS, STIFFER 46lbs/in MODIFIED '77 GS750 SPRINGS (ditched the tightly would progressive section) WITH 135mmx25.4mm THICK-WALL ALUMINIUM (includes 14mm of preload) SPACERS (bicycle seatposts), AND TAROZZI #0040 58mmx175mm FORK BRACE IN PLACE!!!! WOOOOHOOO!!!!!!!!!!

Now I gotta get those calipers back together this afternoon before i visit with my lifetime motivation, my gearhead parents, for an early mother's day! Silicone lube vs silicone based Permatex caliper parts lube for the pistons??? Hmmm...

My wife tried to order Hagon 2810 adjustable shocks from Dave Quinn Motorcycles for my upcoming birthday, and he said "why are you spending $300 on non-rebuildable shocks?" I wanted adjustable dampening. Sounds like the $380 Ikon's may be the best bet, may hold off til after more house remodelling to get those. She told me "sorry for the not surprise, but you'll to call Dave myself, as he had lots of questions that I didn't know the answer to as far as rates, valving, riding style, etc."

 

[Chuck78]

This Permatex Ultra Disc Brake Caliper Lube is AWESOME for assembling calipers. It's brake fluid compatible, super sticky and slick, and can be used on the pistons and seals during assembly - MUCH PREFERRED over the standard method of just wiping some brake fluid on them to slide in. Formulated for sliding pins and pad backing plate contact areas as well, where the super sticky property really helps it stay there for some time to come.