New member intro, GT380 resto project.

Photos and progress of your restorations, even bikes you had but no longer own.

Moderators: oldjapanesebikes, H2RICK, Suzsmokeyallan

jeffz
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.

Post by jeffz »

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.
karl pa
To the on ramp
Posts: 490
Joined: Sat Sep 05, 2015 3:14 pm
Country: us
Suzuki 2-Strokes: GT
Location: southeast pa

Re: New member intro, GT380 resto project.

Post by karl pa »

jeffz wrote: it seems only the center horizontal passage needs plugging.
You must also plug the port from diaphragm to bowl.
jeffz wrote:If you also modify the handle you can have ON and OFF, but no RES
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.
76 GT185
77 GT250
77 GT380
76 GT500
73 GT550
73 GT750
74 GT750
71 T250 scrambler
75 T500 cafe
jeffz
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.

Post by jeffz »

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. :oops:
karl pa
To the on ramp
Posts: 490
Joined: Sat Sep 05, 2015 3:14 pm
Country: us
Suzuki 2-Strokes: GT
Location: southeast pa

Re: New member intro, GT380 resto project.

Post by karl pa »

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.
76 GT185
77 GT250
77 GT380
76 GT500
73 GT550
73 GT750
74 GT750
71 T250 scrambler
75 T500 cafe
jeffz
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.

Post by jeffz »

I get it now, thanks Karl.
I took some pics of the timing gear job today.
Image
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.
Image
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.
Image
The nut holding the gear on was surprisingly tight. The key holding the gear fell out, I almost lost it, duh.
Image
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.
Image
karl pa
To the on ramp
Posts: 490
Joined: Sat Sep 05, 2015 3:14 pm
Country: us
Suzuki 2-Strokes: GT
Location: southeast pa

Re: New member intro, GT380 resto project.

Post by karl pa »

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.
76 GT185
77 GT250
77 GT380
76 GT500
73 GT550
73 GT750
74 GT750
71 T250 scrambler
75 T500 cafe
jeffz
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.

Post by jeffz »

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! :x
sportston
Expert racer
Posts: 1119
Joined: Wed Jul 10, 2013 12:04 pm
Country: England, UK
Suzuki 2-Strokes: FZ50, GP100, RG125 Gamma, GT380, Bandit 1200S

Re: New member intro, GT380 resto project.

Post by sportston »

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! :x
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
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.

Post by jeffz »

Here's what I attempted today:
1. Align timing mark on drive gear to arrow in side case.
Image
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.
Image
Here are the other mesh points where the cover can be installed:
jeffz
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.

Post by jeffz »

Image
Image
Image
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.
karl pa
To the on ramp
Posts: 490
Joined: Sat Sep 05, 2015 3:14 pm
Country: us
Suzuki 2-Strokes: GT
Location: southeast pa

Re: New member intro, GT380 resto project.

Post by karl pa »

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.
76 GT185
77 GT250
77 GT380
76 GT500
73 GT550
73 GT750
74 GT750
71 T250 scrambler
75 T500 cafe
jeffz
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.

Post by jeffz »

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.
Image
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.
karl pa
To the on ramp
Posts: 490
Joined: Sat Sep 05, 2015 3:14 pm
Country: us
Suzuki 2-Strokes: GT
Location: southeast pa

Re: New member intro, GT380 resto project.

Post by karl pa »

Points cam shaft turns counter clockwise, opposite to crankshaft.
76 GT185
77 GT250
77 GT380
76 GT500
73 GT550
73 GT750
74 GT750
71 T250 scrambler
75 T500 cafe
jeffz
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.

Post by jeffz »

Well, I'm back at it. In past weeks I have repainted the battery box, cleaned wiring, repainted the swingarm, and began cleaning the engine. What a mess. I think a couple
of the oil injection banjo fittings got loose decades ago, and the lines, pump, and engine case is dirty, to put it mildly.
Image
jeffz
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.

Post by jeffz »

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.
Image
Post Reply