Honda guy with a Suzuki: GS550 project

[Guest]

Yes, I believe it's ~ '86 GSXR 750/1100. I used the top plate/brace from the Katana and had to oval out a couple of the holes in the fender with a small rat tail file to match the brace. The GSXR spacing is just slightly wider.

 

[Guest]

First, I want to apologize for the pics. My phone sucks and the light in my garage tends to wash it out. It's nearly impossible to get good pics in there. It looks like I used a potato instead of a camera!


I have received a few comments/PM's about the shock and swing arm angle and length. I agree that it's steeper/longer than I would like, but there's a ton of work getting it centered and clearancing for the chain. Many of the pics showed the bike on the lift/center stand and the swinger drooped. I considered a different swinger; GS1100E, Bandit 1200, etc., but at this point I think it would be easier to work with what I have.


I put the wheels back on the bike and set it down on it's on weight. The jack is just keeping the bike from tipping over, not lifting it at all. The shocks are 14" and set on the medium setting. I *still* feel like we could have laid down the shocks a bit more but, as you can see, the shock and swingarm angle aren't as bad as when it was on the center stand/lift and not rear wheel in.


This is workable. And if it just handles too poorly or annoys me too much, I think it would be easier to go with some 13" shocks and maybe even have the chain adjuster slots machined longer and the end of the swingarm cut off a like amount. That would shorten the wheel base, lower the stance and lessen the swing arm angle. All without having to start from scratch.

 

[Guest]

Any updates Scott?

 

[Guest]

As often happens with projects, the work it takes to get it done doesn't look like much. But now the tank clears the carbs, the lines of the tank and seat are nice, the seat latch works, and the petcock (mostly) clears the air filter.


I ended up using BST-36 carbs, Bandit 1200 manifolds, RamAir filters and Bandit 1200 rubber velocity stacks. The OldSkoolSuzuki guys swear that the RamAir filters/velocity stack combo makes for MUCH easier tuning. The RA filter squishes just enough to clear the petcock and leaves more than an inch behind the stack on the #1 throat.








I also re-did the top triple. I put the bar risers in a different spot and used a Bandit 400 dash. It's nearly invisible in the pic, but that black area between the gauges and the triple are idiot lights. The 4oo gauges use a cable drive speedo and the plug is (supposedly) nearly identical to the Katana plug and is supposed to be easy to swap around a wire or two to make it plug and play.
They also have nice cups to hide the rear of the gauges, and it keeps it all in the Suzuki family.

 

[Guest]

I've been pretty side tracked on projects lately. Been thinking about moving in a year or so and spent several weeks doing a "purge" around the house and garage. MASSIVE amounts of stuff to the dump and to Goodwill.
Anyway, I've decided to work on the 1980 GS550 donor/spare parts bike this Winter. That way, I can maybe move it out next Spring and have one less thing in the garage. And one less project to worry about.


Got the stock GS550 engine on the stand. It doesn't need a rebuild, but it was a leaker, so I'll re-seal it this Winter with fresh gaskets and such. The carbs are currently getting rebuilt with new diaphragms.
The frame is a 1980 GS550E frame but, unbeknownst to me, that was the year that Suzuki stopped differentiating between the E and L bikes on the VIN number. I ended up with an L frame and an E donor.
We cut the upper tank mounts off and I have a plan to get the tank rubber mounted through those lower holes, where it needs to be for an E tank.






I have a frame loop with a slight kick up that I will have welded on once the tank mounts are sorted. I will run a bobbed rear fender and a small tail light.








Zip Dawg approves.

 

[Guest]

This bike is my inspiration for the spare parts bike. I will be able to run the stock carbs, exhaust and even the plenum, so that should really simplify tuning.
I'd say I have about 90% of the parts needed to finish this one.

 

[Chuck78]

Man... this build is looking great! I was at first sad to see the GS engine go, but now you have more than made up for it by building an awesome main project bike and repurposing the original engine into a left-for-dead frame! Bravo.

I always said that if I were to ride a modern street bike, I would probably get the last of the air cooled Bandits and make a retro Street Fighter Cafe Racer out of it. I much more endorse chopping up a modern style bike to do a retro Cafe theme than chopping up a vintage bike. You have done similar but using the retro/ vintage bike as a base and putting the modern upgrades on it, including operating the heart of the bike, the engine, to a bandit.

I see on the parts bike, you didn't add any bracing behind the ignition coil area. I think I may have cautioned you about the necessity of adding bracing there in the past. I still strongly stand behind that, the 550 frames will give you a little bit of wiggle when you hit bumps in the road leaned over at highway speeds in curves. With adding a bandit engine, I would say that as an absolute must, a total necessity, to add more bracing to the middleweight 550 vintage frame.

The most critical bracing is what is included on the 80+ 450, 81-83 650, and even the 77 750 frames, but missing on the 550 frames and the GS 400 and 425. The factory put a diagonal tube on each side of the spine down slanted rearward to the side cradle tubes behind the ignition coil area, and they should have put this on all models, not just the 750 and 1000 Etc. Even with the stock engine, it is very much needed.

 

[Guest]

Bracing and welding are on the To-Do list, just gotta get there.

 

[Guest]

Time to figure out some wiring. The hardest part is going to be splicing in the Bandit 400 gauges to the Katana 750 harness. I also have to make the GS550 headlight, taillight and some turn signals work.

 

[Guest]

I recently found a VERY nice 1978 tank on eBay. From the pics, it looked black. When I opened the box, it looked black. As I was clay barring and waxing it, I noticed a blue tint. When I put the tail section next to it (also from a '78), it was obvious that one was blue and one was black.

The tank is a very dark, midnight blue. I believe it to be original paint. What was this color called? Is there a paint code or modern equivalent? I paid too much money for the nicest tail cowl I could find, thinking I would just run O.G. paint parts. But now I need to have the cowl painted to match the tank. Pinstripes, too, but that should be relatively easy as the're just red and gold.

 

[dorkburger]

As close as the bike looks to being rideable, I'd use the parts as is and get a few rips in before winter,

 

[Guest]

I've got ALL of the wiring to figure out before I can do that.

 

[Guest]

Figured out the wiring and heard it run for the first time today!
Still a small punch list of things to do: Fiber washers for the petcock screws, some grommets for the side covers, adjust the clutch a little better, find out why the neutral light isn't working, add pin stripes to the tail cowl, etc., but I actually rode it up and down the street in front of the house today!

 

[steve murdoch]

Wow! Cool looking ride, Scott.
Love the NRC covers. A former member here was responsible for the early edition.

 

[dorkburger]

Looking great. Nice work sir.

 

[Guest]

I ended up selling this bike to my friend. He fiddled with it while he was healing from his moto accident and got it running, but tuning the carbs was being a PITA, so he installed some flat slides.
On the dyno, it made 86 RWHP and 45 lb/ft TQ. He said, in his experience, on his dyno, that's well over 95 HP at the crank. He believes there's more in it with some more jetting changes. He's also upgraded the ignition since then. He said the slotted timing adjuster made a difference in the mid-range.

He also commented that the suspension is really dialed in, which means a lot since my dad and I did it all at home with string and a plumb-bob. I always thought the swingarm was too long, but he says it's the same wheelbase as many Ducatis he works on. He also said it lifts the front wheel easily in 1st and 2nd gear!

I made him promise to give me first refusal if he decides to sell it.​

 

[Guest]

In his shop. After some dyno tuning.

 

[steve murdoch]

Wow, cool ride. That turned out very nice!
The swing-arm does look long especially with the shock mounts at the mid-way point.