GT380 OIL INJECTION SYSTEM ELIMINATION
Moderators: oldjapanesebikes, H2RICK, diamondj, Suzsmokeyallan
-
- On the street
- Posts: 16
- Joined: Mon Jan 24, 2011 11:37 am
GT380 OIL INJECTION SYSTEM ELIMINATION
I have a 1976 Suzuki GT380. I am having a very hard time putting my trust into this old oil injection system as when I'm on the freeway on steep grades, at wide open throttle I'm leaving cars in a smoke cloud haha. Does anyone know the easiest way to cap off this system and run my own pre-mix. Any help would be greatly appreciated. I just don't want to cause any vacuum problems etc.
- johnakay
- I likes them jubblies
- Posts: 2365
- Joined: Wed Oct 15, 2008 11:19 am
- Country: UK
- Suzuki 2-Strokes: bike
Re: GT380 OIL INJECTION SYSTEM ELIMINATION
this can't be done due to the crank bearing needing direct injection of two stroke oil.
this has been ask many times on here.
the engine has been designed this way to eliminate engine seizure.
old way of premix engines use to seized up when some youthfull twist of the throttle
.
if you are belching to much smoke there are several things that can cause this.
1,incorrect setting.
2, modern two stroke oil you don't need so much oil injection-now I'm not to sure but others in the know will answer this.
3,this common. if you been steady riding for a few miles and then give full blast then it will smoke for awhile. this due to build up of un burnt 2 stroke oil.
4, silencer/baffles is in need of good cleaning out. costic soda is good for this.others may have better ideas. this is the old fashion way.
no doubt others will add more. john
this has been ask many times on here.
the engine has been designed this way to eliminate engine seizure.
old way of premix engines use to seized up when some youthfull twist of the throttle

if you are belching to much smoke there are several things that can cause this.
1,incorrect setting.
2, modern two stroke oil you don't need so much oil injection-now I'm not to sure but others in the know will answer this.
3,this common. if you been steady riding for a few miles and then give full blast then it will smoke for awhile. this due to build up of un burnt 2 stroke oil.
4, silencer/baffles is in need of good cleaning out. costic soda is good for this.others may have better ideas. this is the old fashion way.
no doubt others will add more. john
If I wanted to make a life-long career out of
working with the mentally retarded I would
have opened a Harley Davidson Dealership
working with the mentally retarded I would
have opened a Harley Davidson Dealership
-
- My new bike is "IRIS"
- Posts: 1002
- Joined: Tue Oct 14, 2008 8:33 pm
- Location: Suburbs of Centralia, WV
Re: GT380 OIL INJECTION SYSTEM ELIMINATION
Gotta agree with Johnny on this one.
Kevin
Kevin
Everything Commeth
To He Who Waiteth
So Long As He Who Waiteth
Worketh Like Hell While He Waiteth
To He Who Waiteth
So Long As He Who Waiteth
Worketh Like Hell While He Waiteth
- jabcb
- Moto GP
- Posts: 4311
- Joined: Mon Dec 13, 2010 4:32 pm
- Country: USA
- Suzuki 2-Strokes: 69 T350 thru 75 GT750
- Location: southwestern Pennsylvania
Re: GT380 OIL INJECTION SYSTEM ELIMINATION
I agree with johnakay too.
Also suggest you use the best 2-stroke oil.
My GT750 smokes a lot less than when I bought it. Prior owner had been using a cheaper 2-stroke oil. I switched to Bel-Ray SI7 & now it smokes a lot less. Its expensive on a per quart basis, but Suzuki oil consumption is pretty frugal so you don't really use that much 2-stroke oil.
You'll get a variety of answers if you ask which oil is best. Bel-Ray SI7 is a synthetic oil. Some like synthetic and some don't. There are other good choices. Suggest you take a look at the "Oil Forum" catergory if you want more info.
Also suggest you use the best 2-stroke oil.
My GT750 smokes a lot less than when I bought it. Prior owner had been using a cheaper 2-stroke oil. I switched to Bel-Ray SI7 & now it smokes a lot less. Its expensive on a per quart basis, but Suzuki oil consumption is pretty frugal so you don't really use that much 2-stroke oil.
You'll get a variety of answers if you ask which oil is best. Bel-Ray SI7 is a synthetic oil. Some like synthetic and some don't. There are other good choices. Suggest you take a look at the "Oil Forum" catergory if you want more info.
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
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
-
- On the street
- Posts: 16
- Joined: Mon Jan 24, 2011 11:37 am
Re: GT380 OIL INJECTION SYSTEM ELIMINATION
Thanks I appreciate it. Checked my oil pump setting and it is cherry. Custom 3-3 system with brand new silencers, clean baffles. Motul 710 full synthetic injection oil. I'm mainly always on the pipe. Just wanted to make sure this is normal. Gotta love the ol' 2-smoke. Pretty funny seeing the looks on peoples faces when you cloud them a bit. Would you guys happen to know a company that makes cafe tail sections with the dimensions of the GT380. In the middle of molding mine out of fiberglass but wondering if there are any out there. Thanks again you guys rock!
- Coyote
- Moto GP
- Posts: 3404
- Joined: Tue Oct 21, 2008 2:41 pm
- Country: USA
- Suzuki 2-Strokes: GT550x2, GT750, GS1000
- Location: Tulsa, Oklahoma
Re: GT380 OIL INJECTION SYSTEM ELIMINATION
See this link toward the bottom. Contact ja-moo. He may be able to fix you up.
viewtopic.php?f=2&t=4002" onclick="window.open(this.href);return false;
viewtopic.php?f=2&t=4002" onclick="window.open(this.href);return false;
I was born with nothing and still have most of it left.
.
1978 GS1000C
1976 GT550 ongoing money pit.
.
1978 GS1000C
1976 GT550 ongoing money pit.
- Suzsmokeyallan
- Moto GP
- Posts: 4326
- Joined: Fri Oct 24, 2008 9:11 am
- Location: Mostly Barbados, sometimes Florida and western Canada
- Contact:
Re: GT380 OIL INJECTION SYSTEM ELIMINATION
Actually with the modern oils you usually need to back the pump setting off a bit from the stock setting marks. Did you do any plug readings at various throttle settings?
Two strokes, its just that simple.
69 Suz U70
69 Suz T500
72 Suz GT750 cafe
74 Suz TS250
74 Suz GTXVR project
75 Suz RE5
75 Suz GT750
76 Suz TS400
76 Suz GT750
81 Suz GSX1100
86 Suz RG500x2
88 Hon CR500
93 Hon CBR900RR
98 Suz GSF1200x3
15 Kaw Ninja H2
69 Suz U70
69 Suz T500
72 Suz GT750 cafe
74 Suz TS250
74 Suz GTXVR project
75 Suz RE5
75 Suz GT750
76 Suz TS400
76 Suz GT750
81 Suz GSX1100
86 Suz RG500x2
88 Hon CR500
93 Hon CBR900RR
98 Suz GSF1200x3
15 Kaw Ninja H2
-
- To the on ramp
- Posts: 444
- Joined: Mon Oct 20, 2008 5:31 am
- Location: Killen Alabama, USA
Re: GT380 OIL INJECTION SYSTEM ELIMINATION
Cut your pump back and be sure the air filters aren't over-oiled, it will make it smoke and run rich.
2007 Suzuki V-Strom DL650
- tz375
- Moto GP
- Posts: 6213
- Joined: Mon Nov 03, 2008 10:47 am
- Location: Illinois
Re: GT380 OIL INJECTION SYSTEM ELIMINATION
As the guys have said, the crank can be stripped and modified to run on pre-mix but it's not a good idea. Modern oils are much better than the oils back in the day and it is possible to cut back on the oil feed slightly but at your own risk.
Don't bother about plug chops at different throttle settings, it will not tell you anything much unless something is grossly wrong. Plug color is really only relevant when the plug is hot ie at wide open throttle. At less that WOT, it is at best a general indicator if something is completely screwed. You cannot use part throttle plug chops as a guide to adjustment.
Don't bother about plug chops at different throttle settings, it will not tell you anything much unless something is grossly wrong. Plug color is really only relevant when the plug is hot ie at wide open throttle. At less that WOT, it is at best a general indicator if something is completely screwed. You cannot use part throttle plug chops as a guide to adjustment.
- johnakay
- I likes them jubblies
- Posts: 2365
- Joined: Wed Oct 15, 2008 11:19 am
- Country: UK
- Suzuki 2-Strokes: bike
Re: GT380 OIL INJECTION SYSTEM ELIMINATION
here is a guide to two stroke plugs' how to read'
http://ezinearticles.com/?How-To-Read-Y ... &id=170641" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
here I've found these not sure if any help?

Guide : Knowing the Condition of Vehicle Engine From Spark plug
Although small this part must be have special treatment, the function of spark plugs can not be underestimated. Spark plug a vital role in the process of combustion to produce energy, so that vehicles can drive.
Spark plugs are necessary components of the vehicle to start the engine. This component is in charge of producing an electric spark to burn the air fuel mixture in the cylinder vehicle.
A good spark plug capable of working in high temperatures and pressures. Because of work directly related to the engine, spark plugs can be used to identify and find the cause disruption on the machine.
So, when you clean the spark plug at a time can check whether the machine is still excellent condition or have been sluggish, just by observing the head of the spark plug.
Vehicle engines called normal if it is still an insulator and electrode tip spark plugs light gray or reddish brown. This shows the conditions and engine settings and ignition timing in top shape, and still in accordance with the state factories.
If you see the end of the insulator, and the spark plug electrodes covered with a black action je, combustion of the dry but soft, you should quickly check Stelan or injection, choke mechanisms, air filters, if necessary, replace the spark plugs that fit, because most likely there is a lack of fit in these parts. It's nothing, interference with the earlier components will cause a black menjadin automobile exhaust fumes, gasoline wasteful, and difficulty starting when engine is cold.
Have you ever experienced stagnant and slow the engine when the vehicle accelerates fully charged, or explosive exhaust because the fuel is not burned out (misfiring)? If yes, check your spark plugs, would end insulatornya seemed somewhat light brown yellow and green colors sometimes appears a bit wet.
This shows gasoline and other materials such as oil polluted water, or use a less suitable additives. There are many other examples that show the spark plug faces look good or bad conditions of vehicle engines. But do not also forget to take care of the spark plug itself.
Some experts recommend that the mechanical spark plugs are always cleaned after the car runs about 2500 km, and was replaced after 10,000 km to 15,000 km.
for safety riding motorbike : let's check the spark plug before riding.
http://ezinearticles.com/?How-To-Read-Y ... &id=170641" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
here I've found these not sure if any help?


Although small this part must be have special treatment, the function of spark plugs can not be underestimated. Spark plug a vital role in the process of combustion to produce energy, so that vehicles can drive.
Spark plugs are necessary components of the vehicle to start the engine. This component is in charge of producing an electric spark to burn the air fuel mixture in the cylinder vehicle.
A good spark plug capable of working in high temperatures and pressures. Because of work directly related to the engine, spark plugs can be used to identify and find the cause disruption on the machine.
So, when you clean the spark plug at a time can check whether the machine is still excellent condition or have been sluggish, just by observing the head of the spark plug.
Vehicle engines called normal if it is still an insulator and electrode tip spark plugs light gray or reddish brown. This shows the conditions and engine settings and ignition timing in top shape, and still in accordance with the state factories.
If you see the end of the insulator, and the spark plug electrodes covered with a black action je, combustion of the dry but soft, you should quickly check Stelan or injection, choke mechanisms, air filters, if necessary, replace the spark plugs that fit, because most likely there is a lack of fit in these parts. It's nothing, interference with the earlier components will cause a black menjadin automobile exhaust fumes, gasoline wasteful, and difficulty starting when engine is cold.
Have you ever experienced stagnant and slow the engine when the vehicle accelerates fully charged, or explosive exhaust because the fuel is not burned out (misfiring)? If yes, check your spark plugs, would end insulatornya seemed somewhat light brown yellow and green colors sometimes appears a bit wet.
This shows gasoline and other materials such as oil polluted water, or use a less suitable additives. There are many other examples that show the spark plug faces look good or bad conditions of vehicle engines. But do not also forget to take care of the spark plug itself.
Some experts recommend that the mechanical spark plugs are always cleaned after the car runs about 2500 km, and was replaced after 10,000 km to 15,000 km.
for safety riding motorbike : let's check the spark plug before riding.
If I wanted to make a life-long career out of
working with the mentally retarded I would
have opened a Harley Davidson Dealership
working with the mentally retarded I would
have opened a Harley Davidson Dealership
-
- Expert racer
- Posts: 1485
- Joined: Tue May 18, 2010 5:38 pm
- Country: USA
- Suzuki 2-Strokes: Suz, Yam, Honda, Kaw.
- Location: New Hampshire
Re: GT380 OIL INJECTION SYSTEM ELIMINATION
My GT380 did the same thing under the exact situation you sated too. I switched to a "Smokeless" injection oil. The oil must have the later FD rating not just FC. One example is Motul 700?. Another is JP1 smokeless injection. Both work well Motul smells better IMO and now what I us.e
Now my GT380 absolutely will not blue cloud in the scenario you mentioned. What a difference.
Now my GT380 absolutely will not blue cloud in the scenario you mentioned. What a difference.
Current registered, inspected, and running well 2 stroke motorcycles
74 GT250 (T350 upgrade),
76 GT250 (T350 upgrade),
71 T350,
70 T350,
74 GT380,
75 T500,
73 GT550,
75 GT750,
72 Yamaha DS7 (R5 upgrade),
77 Yamaha RD400 (Daytona Cyls),
73 Kawasaki H1 500
74 GT250 (T350 upgrade),
76 GT250 (T350 upgrade),
71 T350,
70 T350,
74 GT380,
75 T500,
73 GT550,
75 GT750,
72 Yamaha DS7 (R5 upgrade),
77 Yamaha RD400 (Daytona Cyls),
73 Kawasaki H1 500