1972 GT550 cafe build - new topic

Retro, Wild, Cafe, etc. The stuff only your imagination can come up with.

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jabcb
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Re: 1972 GT550 cafe build - new topic

Post by jabcb »

sportston wrote:That sparkly frame looks so nice.
The frame is bengal silver powder coat.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
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jabcb
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Re: 1972 GT550 cafe build - new topic

Post by jabcb »

Imagecafe-GT550-0999 by jabcb, on Flickr
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
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jabcb
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Posts: 4240
Joined: Mon Dec 13, 2010 4:32 pm
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Suzuki 2-Strokes: 69 T350 thru 75 GT750
Location: southwestern Pennsylvania

Re: 1972 GT550 cafe build - new topic

Post by jabcb »

Working on the headlight bucket wiring. Will easily fit in the bucket & correct connections will be a lot more obvious than the stock mess.
Imagecafe-GT550-1001 by jabcb, on Flickr
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
User avatar
jabcb
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Posts: 4240
Joined: Mon Dec 13, 2010 4:32 pm
Country: USA
Suzuki 2-Strokes: 69 T350 thru 75 GT750
Location: southwestern Pennsylvania

Re: 1972 GT550 cafe build - new topic

Post by jabcb »

A little more headway. Installed a used late-model clutch + starter clutch that I got via ebay some years ago.
Imagecafe-GT550-1015 by jabcb, on Flickr
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
User avatar
jabcb
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Posts: 4240
Joined: Mon Dec 13, 2010 4:32 pm
Country: USA
Suzuki 2-Strokes: 69 T350 thru 75 GT750
Location: southwestern Pennsylvania

Re: 1972 GT550 cafe build - new topic

Post by jabcb »

Slowly making progress.
Imagecafe-GT550-1082 by jabcb, on Flickr
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
sportston
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Suzuki 2-Strokes: FZ50, GP100, RG125 Gamma, GT380, Bandit 1200S

Re: 1972 GT550 cafe build - new topic

Post by sportston »

Oooh that engine looks tasty.
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Alan H
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Re: 1972 GT550 cafe build - new topic

Post by Alan H »

Early engines are pretty with the taller cowl.
Think of how stupid the average person is, then realise that half of them are more stupid than that.
sportston
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Re: 1972 GT550 cafe build - new topic

Post by sportston »

Alan H wrote:Early engines are pretty with the taller cowl.
Yes and they look engineered nicely. The ram air writing is better than the silly sticker on the later bikes.
But I meant that it was an excellent job that Jab has done on making it look new again. His attention to detail is superb. It puts my bike in the shade.
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jabcb
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Re: 1972 GT550 cafe build - new topic

Post by jabcb »

Credit for the spiffy looking motor goes to forum member Sandman, who did the vapor blasting & clear coating, and to a local shop that did the crankcase & cylinders.

Finally nearing the end of this project. Moved the bike into the garage. Cut the rear fender. Working on electrical & carbs.

Imagecafe-GT550-1129 by jabcb, on Flickr
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
User avatar
jabcb
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Posts: 4240
Joined: Mon Dec 13, 2010 4:32 pm
Country: USA
Suzuki 2-Strokes: 69 T350 thru 75 GT750
Location: southwestern Pennsylvania

Re: 1972 GT550 cafe build - new topic

Post by jabcb »

Rebuilding the carbs with:
needle jet: 192 O-6 (new, got them via eBay a few years ago; stock is O-5)
jet needle: 5DH21-3 (also new via eBay a few years ago, stock)
pilot jet: VM22/210-30 (stock +2.5)
main jet: N100.604/105 (L/R stock +10 for all cylinders)
needle valve: VM26/26-2
new floats

This is for Jemco 3-into-1 & K&N R-1100 angled pod filters. +2.5 & +10 worked out nicely for the GT380 with Higgspeed 3-into-3 & same K&N filters.
Any thoughts or suggestions?
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
User avatar
jabcb
Moto GP
Posts: 4240
Joined: Mon Dec 13, 2010 4:32 pm
Country: USA
Suzuki 2-Strokes: 69 T350 thru 75 GT750
Location: southwestern Pennsylvania

Re: 1972 GT550 cafe build - new topic

Post by jabcb »

Installing the Accent ignition. Very easy to install. There is a good blob of something to protect a few of the components from vibration.

The replacement cam has two magnets & the specs list the dwell angle as 120 degrees. The stock ignition has a dwell angle of around 180 degrees, so the Accent ignition should use less current the stock points.

Imagecafe-GT550-1233 by jabcb, on Flickr
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
User avatar
Alan H
Moto GP
Posts: 3160
Joined: Thu Feb 16, 2012 11:50 am
Country: England
Suzuki 2-Strokes: 4 x GT550s - J, M, A, B.
Location: The Republic of South Yorkshire

Re: 1972 GT550 cafe build - new topic

Post by Alan H »

If there's only 1 pickup and 2 magnets, it's for a twin, not a triple. It either needs three pickups with 3 12v coils and one 'target', or three targets (magnets or optical triggers), one pickup and three 4v coils connected in series.
2 magnets and 1 trigger will spark every 180 degrees, not every 120 degrees as you need for 3 cylinders.

I think you may be mistaking dwell angle for firing interval.

Unless of course, it's a completely new system that hasn't been discussed yet, in which case, please carry on and post more details.
The old system was for the 380 and 750 Suzies and kwak triples. Wasn't it to do with engine rotation?
Think of how stupid the average person is, then realise that half of them are more stupid than that.
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jabcb
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Joined: Mon Dec 13, 2010 4:32 pm
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Suzuki 2-Strokes: 69 T350 thru 75 GT750
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Re: 1972 GT550 cafe build - new topic

Post by jabcb »

The circuit board has 3 pickups 120 degrees apart & is labelled for the “GT 55?”. (The “?” is hidden behind the white sticker.) The replacement cam is labelled “Suzuki GT”.
The manual claims the dwell angle is 120 degrees.

I’m certainly no expert, but this is guess…
The cam has two closely-spaced holes. One is empty & the other has a magnet. 180 degrees away from that pair of holes are another two holes with one empty & one with a magnet.
If this is a north pole + south pole arrangement then the dwell angle of around 120 degrees is span from the magnet in one pair to the hole in the other pair.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
User avatar
Alan H
Moto GP
Posts: 3160
Joined: Thu Feb 16, 2012 11:50 am
Country: England
Suzuki 2-Strokes: 4 x GT550s - J, M, A, B.
Location: The Republic of South Yorkshire

Re: 1972 GT550 cafe build - new topic

Post by Alan H »

I see now. I think I'll stick to points though!! :lol:
Think of how stupid the average person is, then realise that half of them are more stupid than that.
cobraace
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Re: 1972 GT550 cafe build - new topic

Post by cobraace »

Great work looks sharp :clap: what did you do with the JR chamber's that are on the first picture.
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