GT 550 Rebuild

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Stevesturdevant
Still in the Driveway
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Joined: Sun Jun 22, 2014 9:30 am
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Suzuki 2-Strokes: 1974 GT550, 2006 DR650, 2007 GS 500
Location: Louisville, KY

GT 550 Rebuild

Post by Stevesturdevant »

I picked up a 1974 GT 550 from Craigslist. Similar to one I had in the '80s. Not running but it turns over and has good compression.

Image

Expansion chambers from Craigs list also. Made the seat from glued foam board.

Here's what I have so far.
Image

To be continued......
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Suzukidave
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Suzuki 2-Strokes: GT750 x2 97 -1200 Bandit 86 GSXR1100
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Re: GT 550 Rebuild

Post by Suzukidave »

Nice project , i wonder what brand chambers those are ? They are the shortest 550 pipes i have ever seen .
the older i get the faster i was
Stevesturdevant
Still in the Driveway
Posts: 4
Joined: Sun Jun 22, 2014 9:30 am
Country: USA
Suzuki 2-Strokes: 1974 GT550, 2006 DR650, 2007 GS 500
Location: Louisville, KY

Re: GT 550 Rebuild

Post by Stevesturdevant »

Modesett Engineering in Yorba Linda. No longer in business.
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Coyote
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Suzuki 2-Strokes: GT550x2, GT750, GS1000
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Re: GT 550 Rebuild

Post by Coyote »

Definitely not a 74. At least the motor is not. The motor is a 72-73. Even at that the cylinder head looks all wrong for a 550. Help me out guys! What's all wrong here? And the fork gaiters indicate an earlier model as well.
I was born with nothing and still have most of it left.

.
1978 GS1000C
1976 GT550 ongoing money pit.
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tz375
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Re: GT 550 Rebuild

Post by tz375 »

The top picture looks like it's all 73 (K) to me, apart from the chrome headlamp ears. Maybe it was first titled in 74 and that's where the confusion comes from.

The second picture was a 74 tank and side covers but retains early style carbs and head cover.

BTW, anyone know the master cylinder size on a 550 with stock single disk?
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Coyote
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Re: GT 550 Rebuild

Post by Coyote »

14mm. That info and service limits is in my sticky 'General specs and info'. 380 and 550 shared the same one. 750 is larger
I was born with nothing and still have most of it left.

.
1978 GS1000C
1976 GT550 ongoing money pit.
Stevesturdevant
Still in the Driveway
Posts: 4
Joined: Sun Jun 22, 2014 9:30 am
Country: USA
Suzuki 2-Strokes: 1974 GT550, 2006 DR650, 2007 GS 500
Location: Louisville, KY

Re: GT 550 Rebuild

Post by Stevesturdevant »

The tank is off a 74. This one has the frame stamped as 7/74. The chambers are shorter but the silencers are incorporated directly onto the stinger. I understand that these chambers have the stinger inserted into the rearmost cone several inches.
As I understand design, the rearmost cone reflects back the pressure pulse toward the cylinder, the shorter the cone the quicker the travel time, thus operating at a higher RPM

It doesn't run yet so I don't know.
Image
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Alan H
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Re: GT 550 Rebuild

Post by Alan H »

Top pic, colours are 73 K except for chrome ears, headlamp and clocks.
Early engine with late 72/early 73 high top carbs.
2nd pic late tank and panels (Candy Rose GT550A?) with one pod filter fitted (which will cause weak running especially with a 3-1 spannie) and lots of bits missing!!
Fork gaiters on the J were 13 serrations, K were 8, after that no gaiters.

Just enjoy what you have and if it runs OK, then it's fine.
Think of how stupid the average person is, then realise that half of them are more stupid than that.
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Suzukidave
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Re: GT 550 Rebuild

Post by Suzukidave »

Stevesturdevant wrote: these chambers have the stinger inserted into the rearmost cone several inches.
Ah .. that explains the length .. internal stingers :up:
the older i get the faster i was
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