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1978 GS400 Help!!!

  • Thread starter Thread starter TimB
  • Start date Start date
T

TimB

Guest
Hello Everyone,

I am a now the proud owner of a 1978 GS400. The bike was given to me by a co-worker. he purchased the bike in 1985 from a friend. The bike did not start at that time. It has been sitting in his garage ever since. He was clearing out space so I offered to take it off his hands. Looks like it is in great shape!! I plan on spending the winter attempting to do what I need to get it running. The bike appears to be in good shape. Very little rust, under 3000 miles, tires actually look great. The problem is that I know nothing about engine mechanics. I have been a bicycle mechanic for over a decade so I do have some mechanical knowledge/skill. I just don't know where to start with an engine!! Change the oil?? Plugs?? Clean the carbs?? Please help me!!! I will post pictures soon. Thanks!!!

Tim
 
Photos are coming soon(tomorrow...most likely). Started doing an initial cleaning last night and tonight. Looks 100 times better already!! DP, what exactly do you mean by "cranking the engine by hand?". Remember... I know nothing!! I assumed you were talking about the "kick starter". If so... it moves freely but nothing happens. I'm excited for this winter!!!!!

Tim
 
Starting out, you have three things to look at.

Electrical... Points coils plugs etc. Does the bike make spark?
Fuel... Clean the carbs. Do not take shortcuts. Follow Nessism's tutorial. (on Bikecliff's site) Make sure your tank is clean inside.
Air... Is your air box sealed? Are the carb boots sealed? Also, replace the o rings between the carb manifolds and the head.

O oh ya, one more thing. Read everything on Bikecliff's site. Everything, even if it does not apply to your bike, you will learn lots about how these bikes work!
 
I just fixed up an abandoned '77 gs400 this summer. great bike!
I dont have much insight to add to the good advice already posted, except that You should trying to clean out the gas tank a bit before try to start the bike. Mine had good bit of rust-sludge in the bottom of the tank. I eventually did a proper tank cleaning, but initially ( to see if i could even get the bike running,) I just drained the old gas, and (with the tank off ) sloshed a quart or so of new gas around in the tank to free up all the fine rust debris. Drain and repeat. You'll want to remove the petcock for this. You dont want to drain all that crap by running it out thru the petcock. the stuff that came out of mine looked like orange soup!


BYW : your kickstarter moves freely? Like, it engages and the cylinders turn freely, or does the kickstarter freely moves without engaging anything internally?

If its the latter, you may have some problems.
 
Last edited:
pete said:
She doesn't look too bad at all! And that's a huge sissy bar...
Click to expand...

I agree with, Pete. She does not too bad at all. Darn sight better than where I started from on my 400. Be careful passing under low bridges with that sissy bar though;)

Mark
 
I know!! That is one huge bar. I was suprised to find that it does not recline!! I have been doing TONS of reading since my last post. I am now feeling much more confident about this project. So far I have removed the old cracked battery, and removed and drained the tank. I have also been cleaning and polishing. Next I plan on removing the petcock from the tank and cleaning it. I read to use fresh gasoline for this. After that I will tackle the carbs. I have been trying to locate Gunk carb cleaner locally with no success. The only one I have been able to find is a generic Napa can with a dip basket. Any suggestions for a carb dip would be great!!
 
TimB said:
I know!! That is one huge bar. I was suprised to find that it does not recline!! I have been doing TONS of reading since my last post. I am now feeling much more confident about this project. So far I have removed the old cracked battery, and removed and drained the tank. I have also been cleaning and polishing. Next I plan on removing the petcock from the tank and cleaning it. I read to use fresh gasoline for this. After that I will tackle the carbs. I have been trying to locate Gunk carb cleaner locally with no success. The only one I have been able to find is a generic Napa can with a dip basket. Any suggestions for a carb dip would be great!!
Click to expand...

Most guys in the US use Berrimans with good success.

If you can get it over there, there's also a Yamalube carb cleaner from Yamaha that I used and is quite good too. No basket or anything though so you will need to find something to soak them in. I used a cheap sauce pan...
 
Thanks for the info Pete!! I'll keep and eye out for either of those cleaners. I forgot to mention that the gas I drained was perfectly clear. Not murky or dirty looking at all. Hopefully that is a good sign of what is to come as I dig further.
 
TimB said:
Thanks for the info Pete!! I'll keep and eye out for either of those cleaners. I forgot to mention that the gas I drained was perfectly clear. Not murky or dirty looking at all. Hopefully that is a good sign of what is to come as I dig further.
Click to expand...

Good stuff, if what comes out of the tank is perfectly clear then that should in theory mean you have no rust issues.
 
Thanks again for the info guys!! I took the petcock apart tonight. Was not too bad looking other than some gummy stuff(but VERY little of it). When I drained the tank I did note that fuel only emptied when I switched it to "Reserve". From what I read, "prime" should empty fuel no matter what the fuel level(which was about 3+ gallons!!). Any idea why?? Also any idea where to locate some new rubbers for the petcock. They appear to be in good shape but I would rather replace them while I am tearing things apart rather than after everything is assembled. Thanks!!!!

Tim
 
You sure you had it on reserve? If it's a vacuum operated fuel tap like most of them are, then it shouldn't just drain fuel on either "On" or "Res", only on "Prime".

Mine has a screw for the prime function, the tap just switches between "On" and "Res".

Sounds like either something's wrong with your fuel tap or maybe it really was in the Prime position?

As for replacing the rubbers, there are rebuild kits available for some of them at Z1 or on eBay and there have been mixed reports of success and failure with them.

My suggestion would be just buy a new one if you can, mine was less than $80 brand new from Boulevard Suzuki...
 
Thanks Pete!! After looking at it with a different perspective I think I was using the prime function. Mine looks almost exactly like this one...

http://members.dslextreme.com/users/storagecliff1/images/suzuki_petcock_rebuild.pdf

I was looking at it as if it was an arrow pointing towards "Fuel", "Res", or "pri". Now I realize that the circle end of the lever indicates the position. Good to know it's not junk!! I'm going to attempt to clean it and re-use the current rubber for now. Once I see if I can get the bike running then I will go back and replace if needed since it's an easy fix.
 
The 78 petcocks are around $300,ask me how I know.Had a good one I sent off to FC with that 79 400 tank.Really wish I had it back now:(
 
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