Suzuki GT550 Cafe and Restomod

kadavenport

Been Around the Block
Hey Guys,
A few years ago my 1975 Suzuki GT550's engine locked up while I was riding down a highway. Luckily I was able to keep it up right, and slid to a stop on the side of the road. After trailering it home, I was able to get it unstuck, but when turning the engine over it sounded like a can filled with buckshot. Long story short, I was pretty sure it had a fried piston and crank bearings and I parked her not having the time and money to fix it at the time. Life happened and after two kids, and after bit of time I got the itch to get her back on the road.

During my motorcycle hiatus, I took up leather work and kept up on my welding projects (pic below is my first attempt at welding an alloy motorcycle seat), and restoring my dad's 1972 Jeep CJ5.
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Without tearing into the engine, I started sourcing parts for a rebuild. I was able to get a crank in good condition, pistons, jugs, gaskets, seals and bearings.

I also decided it was time to make the bike sportier and lighter, but want to preserve the stock parts and mounting points on the frame. So I ordered a new headlight bracket, and clip-ons.

After setting the practice seat and clip-ons on the bike, I decided I was ready to really take on this project (and my daughter was supportive too).
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Thanks, I must have had luck during the strip down because everything went easy. I did the regular routine of using a baggy and sharpie to label all the bolts and small part and stored them on shelves in my basement. Once the engine was out I cleaned the jugs, and head using a mixture of boiling water/vinegar, and then added baking soda after scrubbing the parts until the mixture was neutral. Then I rinsed the parts in my dishwasher. My wife and I made a deal that if it broke, I had to buy her a new stainless still dishwasher (luckily it didn't).

Before:
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During:
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After:
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Ultimately I will be attempting an aluminum tank and seat. This is the template I've started for both.

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But priority 1 is getting running after rebuild, tune, and back on the street.
 
When I pulled the old jug I confirmed the trashed piston and crank. The connecting rod bearings were no where to be found, and the piston skirts were bashed to pieces.
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Pulled the engine and started the tear down.
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Empty frame:
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Some thing satisfying about parts piles.
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Man, these two strokes collect a ton of oil and grime over the years:
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After splitting the cases I cleaned them with Gunk Gel. It only did a decent job, so more elbow grease than anything else. Then using denatured alcohol I go to work on the left over gasket material. My dad came over and leant a hand. I think we put in about 3 hours cleaning.
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Pulled an all nighter getting the engine back together and torqued down. Gotta love that Suzuki casts the torque order on the cases, and hate them for making the clutch bolts out of play-dough. Yes, I broke a clutch bolt off in the basket and wasted several hours drilling out the bolt, extracting it, drilling the basket and tapping for a larger bolt. The torque specs for the clutch bolts is only 7-10lbs and this was the second one I broke off.

At 8AM the next morning I bolted the engine back in the 550.
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It'll be coming back out, but I want to make sure its running right.
 
I think the crank bearing bearing died first, a common problem on these bikes and let the piston bounce around in the jug. I was afraid it could have been an oiling issue, but all lines are flowing correctly and the pump is working.


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Well I guess it didnt happen then :). I've already taken the carbs back off. The float is sticking on the middle carb and dumping gas everywhere. Try again this weekend.


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Re: Suzuki GT550 Cafe and Restomod (Aluminum Seat Fab)

So, decided to take a break from the mechanicals for a day and worked on the seat. I also wasn't happy with the boxier sear design, so I did a rounded version (uses less material too) and liked it better. After the wife and kids went to bed, I cut out pieces and got them bent up. I'm really pleased with the fit. Next, it will be OA welding them up, trimming and polishing.

New GT550 Seat Design
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Templates
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Posterboard Mockup
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Po' Man's Slip Roll
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Fitment
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If all goes well with the seat, it will get shortened so a tank similar to the one on the T500 below will get used.
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I took a 2x2 and used a holesaw bit to drill a hole a bit bigger than a scrap steel tube I had in the basement. The hole was offset, so when clamped to my work table it is tight on the metal I was working, but allows the metal to slide under it with some force. Starting in the middle lightly pull up on the metal in intervals as you work toward the edge of the metal. When you get to the end, pull the piece out, spin the piece 180 degrees, slide back under the bar and lightly pull up on the metal as working toward the other end.
Warning... it takes a long time, and if you pull up too much you will crease versus putting a curve in the metal.


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Also, I used a piece of foam board between the bar and the piece to pad and also allows the piece to slide under the bar a bit easier.


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Re: Suzuki GT550 Cafe and Restomod (Cardboard Tank Template)

Hey Guys,
Been really busy with work, so the motorcycle has slowed down a bit. However, I was able to get a hold of Pete Williams and he has been guiding me through OA welding aluminum. He's been a great resource, and if you haven't watched his youtube video on how to make an "alloy" motorcycle tank you should. He makes it seem so easy, and I can tell you its not.

Any ways, as I prep to weld up and the seat and now tank, thought I'd tease with the cardboard mockups.

Design from Google Sketchup:
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Transferred to Cardboard:
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Cardboard Mockup on the GT550:
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