'75 Suzuki GT380 restoration

[MightyJoe]

Hey all! Recently started a resto on a bike I bought back in '93 and stored in my mother's garage for 19 years. It never really ran well when I was just 21 - and at the time I didn't have time, money, interest... or ebay. Now, I have a little bit of time on weekends, a couple dollars in my pocket, MUCH more interest and of course, ebay... and I'm hoping to get 'er running by spring '13. Will be posting pics/updates and probably a lot of questions along the way. Looking for'd to (virtually) meeting ya'.

While I'm figuring how to post pics to this forum, here's some on my FB page: https://www.facebook.com/media/set/?set ... 895b2135a1" onclick="window.open(this.href);return false;


-Joe-

[Scorch]

Welcome aboard the board, Joe!

[MightyJoe]

danke shoen, herr scorch.

[MightyJoe]

Challenge #1:
I have spark. I have compression. I have no fuel.

Removed petcock easily enough without the tank falling apart (which I imagined it might do). Opened 'er up and found the top section was completely gummed up... nothing a li'l carb cleaner couldn't handle, though.

Opened the bottom bowl and it looked pretty good, though I have a rebuild kit on the way and am going to replace every part that I can.

Question 1: the petcock has "res", "pri" and "on" settings... no "off" (for winter storage, tear-down, etc)???

Question 2: should I assume the circle indicates which setting the petcock is on - and not the 'pointer' at the opposite end?

Question 3: there's a high (pri?) and low (res?) filter. the lower one does not appear to be replaceable. as you can see, the filter screen isn't in the best of shape. is there a way to glue(???) a new screen over the existing materials?

[Scorch]

I think you're right about the circle end indicating the position. My petcock was the original so I replaced it with a new OEM from Suzuki. It came painted black, did not look OEM at all. I still have trouble with the carbs starving occasionally if I leave it in ON. It is vacuum operated, so for me, ON is when the bike is not running and PRIME is when it is running, this fixed the issue with the carbs starving.

[r3tro74]

That looks like the petcock on my 74 gt550. The circle does Indicate the position.

The lower screen is replaceable. it pushes down into the hole instead of over a tube like the other one. I think they are the same part#. The parts catalog does not show the lower, but the upper screen shows "Quanity: 2"

"ON" is "OFF" with the bike not running, a vacuum line from the carbs pulls on a diaphram inside of the petcock to open and allow fuel flow w/ running.

I don't think the diaphram is available so don't dmamge it when disassembling. Be sure to replace the small O ring on the center of the diaphram or it will flow gas all the time.

Other members have found replacement petcock assys from other applications that fit.

[MightyJoe]

thanks for the petcock info, fellas... here's my next rookie Q for ya'll: right side of engine, where the clutch plates, etc are located... before opening 'er up to replace my chewed up gears, I drained [oil? transmission fluid?] from it. once I get the appropriate pieces swapped out, WHAT IS THE FLUID I'm replacing?!? preferences on brand, etc? also, there is no dipstick, just a fill plug on top... should I assume this means I just fill'er to the top?

(have I mentioned I'm new at all this?)

thanks!

[Rhencullen]

also, there is no dipstick, just a fill plug on top... should I assume this means I just fill'er to the top?

There is a bolt on the engine casing near the kickstart that is a filler level ( the oil can take a long time to work down ), so I leave it overnight with a tray underneath. I think its 1500cc from memory.

WHAT IS THE FLUID I'm replacing?!? preferences on brand, etc?

It's oil for the gearbox - I simply use 10/40 engine oil as recommended in the owners manual, although some people use gear oil.

[MightyJoe]

There is a bolt on the engine casing near the kickstart that is a filler level ( the oil can take a long time to work down ), so I leave it overnight with a tray underneath. I think its 1500cc from memory.

yep... says 1500cc right on the side.

It's oil for the gearbox - I simply use 10/40 engine oil as recommended in the owners manual, although some people use gear oil.

Owner's manual? Could that be different from the "service manual" from Suzuki I have? Only hint I'm finding under engine/lubrication system - aside from the CCI - is "oil bath" with no specs as to the type of oil.

[Scorch]

I use 10-40w, or 30w, whichever I have at hand. I don't think it's mission critical, just as long as there is some oil there. I pour the number of cc's stamped on the side into it and away we go.

[MightyJoe]

Latest update: friend with much more bike/mechanical experience than I came over this evening & helped me replace the 2 (known) chewed up gears... we discoverd one more damaged gear on the backside of the clutch plate "basket" (according to parts catalog, it's the clutch gear assy, primary driven. pt # 21200-33003 if I'm reading things correctly.)

local suzuki/kawasaki shop guys tell me the warehouse in pennsylvania still has a LOT of old suzi-stock, so I'm gonna check w/them before hitting up ebay this time around.

[MightyJoe]

this may already be addressed elsewhere in the forum, but the search function has been "unavailable at this time for the last couple of days", so I'll post here for now and see where we can get...

i swapped out the speedo/tach console and it was fairly straight-forward with its modular connections, but there were 6 wires coming from the headlamp that were just spliced to my old console. (the replacement console had all the modular connex intact, but I had to cut off the one that has 4 wires IN it, plus 2 loose ones to the side to match 'em up to the existing bike wiring) it seems strange in that the wires don't necessarily pair up with the same colors...

console side wires are: brown, gray, red, red, orange, orange
headlight side wires are: green, green, red, red, white, white

(wires are connected to each other in the order listed above; meaning console brown to headlight green, etc...)

without tearing open BOTH consoles, I had to make some guesses on which red went to which red, for example, but they must've been some pretty darned good guesses... I know I have some things working correctly.

* When I turn the key, the green neutral light comes on.
* When I turn the lights on, headlight and console lights come on.
* When I turn the lights to HI-beam, the headlight does NOT change (I'm assuming it's on low) and the left side (speedo) light goes OFF.
* Turn signals will come on, though they are constant - not flashing... except the left signals will flash if I give the switch a little jiggle.
* Horn does not work, though it wasn't working before I started the swap-over, either.

so, my questions are:

1) where do I begin to get the hi-beam/speedo light to function correctly
2) what could be making the turn-signals not work correctly?
3) what might I be missing w/the horn?

I do have a wiring diagram, but it's not color coded in any way. Any help/suggestions/etc?