New member intro, GT380 resto project.
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- On the street
- Posts: 35
- Joined: Wed Sep 04, 2019 2:34 pm
- Country: USA
- Suzuki 2-Strokes: GT380
- Location: Mesa, Arizona, USA
Re: New member intro, GT380 resto project.
Thanks to all for the welcome, and suggestions.
Im not familiar with all the petcock designs, but looking at mine, it seems only the center horizontal passage needs plugging. Then it doesnt matter if the vacuum is connected, and the original ON and RES. positions become OFF, and PRI becomes RESERVE, sacrificing ON. If you also modify the handle you can have ON and OFF, but no RES.
Progress today was removing the exhaust, Rt. footpeg, kick lever, and brake pedal, which was bent and being replaced. I clean/soak parts in Evapo-rust as they come off. I hate storing dirty parts. Re-assembly is more fun with clean parts.
Im not familiar with all the petcock designs, but looking at mine, it seems only the center horizontal passage needs plugging. Then it doesnt matter if the vacuum is connected, and the original ON and RES. positions become OFF, and PRI becomes RESERVE, sacrificing ON. If you also modify the handle you can have ON and OFF, but no RES.
Progress today was removing the exhaust, Rt. footpeg, kick lever, and brake pedal, which was bent and being replaced. I clean/soak parts in Evapo-rust as they come off. I hate storing dirty parts. Re-assembly is more fun with clean parts.
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- Yeah Man, the Interstate
- Posts: 508
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- Country: us
- Suzuki 2-Strokes: GT
- Location: southeast pa
Re: New member intro, GT380 resto project.
You must also plug the port from diaphragm to bowl.jeffz wrote: it seems only the center horizontal passage needs plugging.
You need to study all the passages and flow, I modified 5 of the newer style like yours and they work fine with off on reserve, and only cost $1.50 for two set screws.jeffz wrote:If you also modify the handle you can have ON and OFF, but no RES
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- On the street
- Posts: 35
- Joined: Wed Sep 04, 2019 2:34 pm
- Country: USA
- Suzuki 2-Strokes: GT380
- Location: Mesa, Arizona, USA
Re: New member intro, GT380 resto project.
Thanks, Karl, you are right. I did study, but I need to do some more. I suspected I would have gas all over the bike and myself as soon as I put gas in the tank.
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- Yeah Man, the Interstate
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- Location: southeast pa
Re: New member intro, GT380 resto project.
I took one of my spares apart to check, if yours is the same, looking at the valve with the handle removed, it has a 5 hole gasket. the hole at the 12 o clock position is your main tank supply, the hole at 3 o clock is the reserve supply, the hole at 6 o clock is discharge to fuel line, center hole goes to diaphragm,this is one needs plugged, hole at 9 o clock is blank goes nowhere.
when modified handle is turned front, it connects main supply 12 and reserve supply 3 and center hole and 9 o clock blank, gas can't flow.
when handle is turned down, it connects main supply 12, center hole, and fuel line 6, and 9 o clock blank, on position.
when handle is turned to rear, it connects 9 o clock blank, center,reserve supply 3, and fuel line 6, reserve position.
The port between the diaphragm and bowl must be plugged also or gas will back feed up and out diaphragm chamber.
Not to difficult to do. I never had much luck rebuilding vacuum plungers, always seem to seep fuel out fuel line, and be a pain if you need to remove tank.
when modified handle is turned front, it connects main supply 12 and reserve supply 3 and center hole and 9 o clock blank, gas can't flow.
when handle is turned down, it connects main supply 12, center hole, and fuel line 6, and 9 o clock blank, on position.
when handle is turned to rear, it connects 9 o clock blank, center,reserve supply 3, and fuel line 6, reserve position.
The port between the diaphragm and bowl must be plugged also or gas will back feed up and out diaphragm chamber.
Not to difficult to do. I never had much luck rebuilding vacuum plungers, always seem to seep fuel out fuel line, and be a pain if you need to remove tank.
76 GT185
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73 GT750
74 GT750
71 T250 scrambler
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77 GT250
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76 GT500
73 GT550
73 GT750
74 GT750
71 T250 scrambler
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- On the street
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- Suzuki 2-Strokes: GT380
- Location: Mesa, Arizona, USA
Re: New member intro, GT380 resto project.
I get it now, thanks Karl.
I took some pics of the timing gear job today.
I stared at this diagram for days, but couldn't see how you could take the right side case off without removing the ignition timing plate. They have some
ominous warnings in the manuals about messing with the breaker cam fitting nut before the case is removed from the engine. So I ignored not understanding
and just took the screws out and started tapping and prying and worked it off. Sure enough, the timing shaft, bearing, driven gear, etc. all came with it.
The drive gear stays in the engine case.
The gear was cracked. Partzilla had one in stock. I also ordered the bearing and seal, but probably won't use them. I think the bearing is fine, but will get a
second opinion.
The nut holding the gear on was surprisingly tight. The key holding the gear fell out, I almost lost it, duh.
The case is filthy, and the last guy used a blue silicone and the remains of the original? gasket to seal it up. I got some gaskets with the bike, hope one's there.
I took some pics of the timing gear job today.
I stared at this diagram for days, but couldn't see how you could take the right side case off without removing the ignition timing plate. They have some
ominous warnings in the manuals about messing with the breaker cam fitting nut before the case is removed from the engine. So I ignored not understanding
and just took the screws out and started tapping and prying and worked it off. Sure enough, the timing shaft, bearing, driven gear, etc. all came with it.
The drive gear stays in the engine case.
The gear was cracked. Partzilla had one in stock. I also ordered the bearing and seal, but probably won't use them. I think the bearing is fine, but will get a
second opinion.
The nut holding the gear on was surprisingly tight. The key holding the gear fell out, I almost lost it, duh.
The case is filthy, and the last guy used a blue silicone and the remains of the original? gasket to seal it up. I got some gaskets with the bike, hope one's there.
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- Yeah Man, the Interstate
- Posts: 508
- Joined: Sat Sep 05, 2015 3:14 pm
- Country: us
- Suzuki 2-Strokes: GT
- Location: southeast pa
Re: New member intro, GT380 resto project.
On a 380, you may want to set the timing before you bolt up everything and fill with oil. On mine I lined up the timing marks but it fell on a tooth, so I turned points shaft so teeth would mesh, but I couldn't get timed proper, and ended up opening back up and turning to other side of tooth. I use dial gauge to set timing.
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74 GT750
71 T250 scrambler
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77 GT250
77 GT380
76 GT500
73 GT550
73 GT750
74 GT750
71 T250 scrambler
75 T500 cafe
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- On the street
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- Suzuki 2-Strokes: GT380
- Location: Mesa, Arizona, USA
Re: New member intro, GT380 resto project.
More fun to come, eh? Thanks for the heads up.
Today is a day of non-enthusiasm. Cleaning off caked-on grime is a PITA!
Today is a day of non-enthusiasm. Cleaning off caked-on grime is a PITA!
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Re: New member intro, GT380 resto project.
Not to mention all that horrible blue sealant some PO has laid on with a trowel! Some guys just don't understand the term "thin smear". Make sure you get it all off, so it doesn't get into places it shouldn't after the rebuild. Following this thread with interest. Keep up the good work.jeffz wrote:More fun to come, eh? Thanks for the heads up.
Today is a day of non-enthusiasm. Cleaning off caked-on grime is a PITA!
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- On the street
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- Joined: Wed Sep 04, 2019 2:34 pm
- Country: USA
- Suzuki 2-Strokes: GT380
- Location: Mesa, Arizona, USA
Re: New member intro, GT380 resto project.
Here's what I attempted today:
1. Align timing mark on drive gear to arrow in side case.
2. Install case cover with red line (L mark on points cam) aligned with line (yellow painted) in the cover. Not happening. This results with 2 teeth
meeting head to head. I took a bunch of pics where the gears meshed. Close, but not perfect. I would either have to cheat the drive gear off its
mark, or settle for where the cam mark is landing.
This is where it lands.
Here are the other mesh points where the cover can be installed:
1. Align timing mark on drive gear to arrow in side case.
2. Install case cover with red line (L mark on points cam) aligned with line (yellow painted) in the cover. Not happening. This results with 2 teeth
meeting head to head. I took a bunch of pics where the gears meshed. Close, but not perfect. I would either have to cheat the drive gear off its
mark, or settle for where the cam mark is landing.
This is where it lands.
Here are the other mesh points where the cover can be installed:
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- On the street
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- Joined: Wed Sep 04, 2019 2:34 pm
- Country: USA
- Suzuki 2-Strokes: GT380
- Location: Mesa, Arizona, USA
Re: New member intro, GT380 resto project.
I don't understand why it has to be dead on, anyway. Isn't that why you rotate the points plate, to fine tune where the spark happens?
The gears are meshing "in the ballpark". When you use the dial gauge to set TDC vs spark via rotation position of the points plate, that is where
the timing precision comes from, right? Maybe I'm in over my head. Luckily, I have a couple friends that can come over and help me on this.
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- Yeah Man, the Interstate
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- Location: southeast pa
Re: New member intro, GT380 resto project.
Yep that's what I advised about.
Yes you rotate the points plate, but if it is like mine, you will find the screws in the plate slots will be all the way to the end of the slots.
On mine, I went on the retard side of the cam tooth, I got proper timing but have very little adjustment in the points plate slot.
Yes you rotate the points plate, but if it is like mine, you will find the screws in the plate slots will be all the way to the end of the slots.
On mine, I went on the retard side of the cam tooth, I got proper timing but have very little adjustment in the points plate slot.
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71 T250 scrambler
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76 GT500
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75 T500 cafe
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- On the street
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- Country: USA
- Suzuki 2-Strokes: GT380
- Location: Mesa, Arizona, USA
Re: New member intro, GT380 resto project.
Today, I rotated the cam drive gear clockwise so that the pointer was aligned with the first space counterclockwise from the punch mark. They should
not be telling you to align with the punch mark, since you will just end up trying to mate a tooth and a tooth.
The case then went on in a few seconds, and the mark is now almost perfect.
Anyone know which way the cam drive gear rotates when running?
Guess I can tighten the side case on now. Hope it doesn't leak! Time will tell..
Back to cleaning the gook off the engine and frame Monday.
not be telling you to align with the punch mark, since you will just end up trying to mate a tooth and a tooth.
The case then went on in a few seconds, and the mark is now almost perfect.
Anyone know which way the cam drive gear rotates when running?
Guess I can tighten the side case on now. Hope it doesn't leak! Time will tell..
Back to cleaning the gook off the engine and frame Monday.
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- Yeah Man, the Interstate
- Posts: 508
- Joined: Sat Sep 05, 2015 3:14 pm
- Country: us
- Suzuki 2-Strokes: GT
- Location: southeast pa
Re: New member intro, GT380 resto project.
Points cam shaft turns counter clockwise, opposite to crankshaft.
76 GT185
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76 GT500
73 GT550
73 GT750
74 GT750
71 T250 scrambler
75 T500 cafe
77 GT250
77 GT380
76 GT500
73 GT550
73 GT750
74 GT750
71 T250 scrambler
75 T500 cafe
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- On the street
- Posts: 35
- Joined: Wed Sep 04, 2019 2:34 pm
- Country: USA
- Suzuki 2-Strokes: GT380
- Location: Mesa, Arizona, USA
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- On the street
- Posts: 35
- Joined: Wed Sep 04, 2019 2:34 pm
- Country: USA
- Suzuki 2-Strokes: GT380
- Location: Mesa, Arizona, USA
Re: New member intro, GT380 resto project.
Did more cleaning and removed the oil pump and lines. Broke the end off the longest line. I knew they were a little crispy, thought I was being careful... I noticed someone
selling a set of lines broken exactly like mine. Is he nuts, or can you repair them? I'm gonna try to, by slipping a connector over the ends and epoxy-ing.
selling a set of lines broken exactly like mine. Is he nuts, or can you repair them? I'm gonna try to, by slipping a connector over the ends and epoxy-ing.