Oil lines?

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sdc1992
On the street
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Joined: Mon Jun 13, 2016 1:31 pm
Country: USA
Suzuki 2-Strokes: GSX750, 1974 GT380
Location: North Carolina

Oil lines?

Post by sdc1992 »

Hello Again. I've got a puzzling question maybe. The 380 runs great now and pulls very strong even in 6th gear. I'm seeing a small amount of what looks like crankcase oil that leaks out onto the top of the engine under the carbs. I pulled the carbs off for the hundredth time and noticed that there appears to be an oil line broken off. Its where the three black lines come out of the case under the carbs. two of the lines run around to the front of the engine and plug in under the heads. the broken line sticks out about 3 inches. I've not seen where the rest of the line would have went to. I can pull the line in and out a little. it almost looks like a crankcase vent or something. I am thinking this is where the oil is coming from but am not sure. I also lave a leak either from the gear lever seal or the front sprocket seal but they will be tended to another day. Thanks for any input on this

Scott
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jabcb
Moto GP
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Suzuki 2-Strokes: 69 T350 thru 75 GT750
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Re: Oil lines?

Post by jabcb »

Those are the SRIS lines. They connect the crankcase of one cylinder to the inlet of another.
The purpose is to recirculate excess oil in the bottom of the crankcase & reduce smoking.
SRIS was eliminated on later GT380 models.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
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yeadon_m
Road race school
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Suzuki 2-Strokes: GT380B, GT550B, GT750A, GSX1400

Re: Oil lines?

Post by yeadon_m »

+1 on SRIS. These vent from one way valves screwed into the lower front of the motor and the black lines go to brass stub tubes cast into the cylinder intakes.
You can eliminate it per later factory models. If you retain it its VITAL that there are no air leaks, or it will be dangerously lean and may hole a piston. The hose may have simply fallen off the stub. These should be held on tight with little split cylinder-shaped hose clips slid over the hose/stub junction.
Cheers,
Mike
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