82' GS 650 Problem...Soooo close!

PancakeShake

PancakeShake

Been Around the Block
Alright.

We have ANOTHER project bike going.

82 GS 650 L. We bought it running. Brought it home and did a few laps around the neighborhood. Seemed to run pretty decent. We didnt have a key for it so we had to wire up a switch to make it run, which meant we also couldn't get into the gas tank.

After about 20mins on the bike is started sputtering.

So we decided seeing it had been sitting for a while before we bough it, we would clean the carbs and ge into the tank.

- Got the tank open with force, looked good inside'
- Got the carbs off, nice and clean
- Put air through the carbs to make sure they were all free'd up
- Put the carbs back in the bike, new gas, brand new plugs..........bike wouldnt start

We put some starter spray in the heads and the bike fires up immediately, but then dies out quick.

So we determined the gas isnt getting into the heads.

The float bowls are full of gas, so the floats arent stuck or jammed. And all the jets were cleaned.

WHY WHY WHY would there be no gas getting to the engine?
 
Swivel said:
Drain all the carbs a lot out the drain screws and put in fresh gas.It could be a tiny amount of water in the float bowls.Take of the gas tap and clean the filter.....
Click to expand...

we have drained the carbs and re-tried this whole thing 3 times now with new clean gas. The floats have plenty of good clean gas in them. I dont understand how the gas wouldnt be making it to the headers if there is plenty of gas in the float bowls...

i would say maybe its the float height, but there seems to be alot of gas in them, and the bike ran before and we never adjusted them so i dont see why they would be off now...
 
Swivel said:
You haven't given enough info,it's like stabbing ghosts in the dark.

Have you put the tanks vacuum and gas lines on the wrong way around? Is the choke jammed on? it there a birds nest (or rag) in the airbox? Have you got the spark plugs all gummed up with starter spray?(don't use starter spray with bike motors,its not a Jeep or a tractor!).Have you wrecked the CDI or Coils by wiring it to start wrong? GS Suzuki motors can be very hard to start if the valve adjustment is tight.....A small propane torch is the best way to clean oily or gummed up spark plugs,get them very hot right down into the ceramic for about 45-60 seconds and let it cool to cold somewhere safe.....
Click to expand...

- Choke is free to move and smooth
- Air box has been open, clean as a whistle
- Gas line and vacuum lines are in the right spot
- Spark plugs are great, we took them out after using spray and they looked perfect
- Wiring is fine

Its a damn mystery.

Bike has spark and fires up immediately with a bit of gas in the heads, but once that small amount of gas runs out, the bike dies.

The gas isnt being sucked up out of the bowls, so the needles arent doing there job right? I feel like that means there is a vacuum problem.
 
It's not a mystery at all.
Bike was running, you did something, it doesn't work.
Re-do what you did and put it right.
Check all the wiring under tank/seat as you may have displaced something.
 
crazypj said:
It's not a mystery at all.
Bike was running, you did something, it doesn't work.
Re-do what you did and put it right.
Check all the wiring under tank/seat as you may have displaced something.
Click to expand...

Well we didnt do anything but pull the carbs out and re install them. We cant "redo" anything because we never changed anything.

Can someone explain to me how the needles work? And what/where/how many vacuum systems there are on a bike?

I really think its a vacuum issue because there is good spark, carbs have plenty of fuel and are clean, and the air is free. But the gas doesnt make it from the carbs to the engine. SO that's vacuum right?
 
OK, so 'another project' implies your building something for sale?
If your a bike tech, fix it, if not, stop selling shit you know nothing about
You obviously DID do something
Bike was running and now it isn't, they only thing that changed is you took cabs apart and re-fitted them
ergo, you fucked something up\no one here can point you in any direction until you admit you caused problem.
If you changed nothing, (even by accident?) it will still run at least the same as it did before you screwed with it
BTW, it's not vacuum that moves air, it's pressure differentials that PUSH air into cylinder
Bernoulli principle will explain things on how caburettor works
http://en.wikipedia.org/wiki/Bernoulli%27s_principle
 
Not selling anything.

Just 4 of us, and our 4th bike.

I mean we obviously messed something up, but we have reinstalled carbs like 1000 times and its pretty simple. And we didnt even rebuild anything. Took them off, looked at them, looked clean, put them back on.

I feel like were missing a simple part that is keeping it from going.
 
You need to poke all the jets and emulsion holes with a copper wire.
It's softer than the brass so will clean out any corrosion but not enlarge holes
You need to look at jets/drillings with a x10 jewelers loupe
You need to check float levels and set them to minimum spec.
Pilot jets may need changing as 650 ran real lean (depends on model/year/carb number)
I was working as service manager in Suzuki dealer when 650 was launched
 
crazypj said:
You need to poke all the jets and emulsion holes with a copper wire.
It's softer than the brass so will clean out any corrosion but not enlarge holes
You need to look at jets/drillings with a x10 jewelers loupe
You need to check float levels and set them to minimum spec.
Pilot jets may need changing as 650 ran real lean (depends on model/year/carb number)
I was working as service manager in Suzuki dealer when 650 was launched
Click to expand...

Sweet deal, I try all this.
 
Update:

Pulled the carbs again.

- Took out every single jet, soaked them all in carb cleaner then ran compressed air through them. Nice and clean.
- Cleaned out the gas line with a little gas and air, Nice and clean.
- Adjusted float heights to 22.4mm as said in the manual.
- Made sure the rest of the carbs were clean and ran air through every jet/hole/port I could find.
- Carbs looked great, re-installed them.

- Carbs to carb boots
- Carbs to air box boots
- Gas line to gas line port, big center on on carb.
- Vacuum line from rear of petcock to the 2nd carb's vacuum port
- Choke installed

New gas in tank, petcock on prime, hit starter with choke on....Nothing.

Is there anything else it could be other than carbs?

And sorry if I came across like I was insulting anyone, new to this whole thing and just trying to learn. I really appreciate the help form you guys.
 
Swivel said:
Take the carb diaprams+slide out and check for pin sized holes by stretching them very carefully and looking up to the daylight.....Shitty old plug leads and caps won't help the running at all.....Clean the slides and slide hole in the carb body to make sure there is no dust making the slide sticky under vacuum.....I think you may have a wiring shorting out somewhere on frame affecting the ignition....Old bikes can be full on cans of worms.....
Click to expand...

I did the slides when I cleaned the carbs tonight. But I will def check for small holes tomorrow.

Now, when I put a small amount of gas in each head and hit the start, the bike fires up IMMEDIATELY and runs until that gas is burnt out, so like 3 seconds. Would that still happen if there was a bad ground?

***All 4 heads have spark and new plugs in them
 
Have you accidentally turned the butterflies closed when you cleaned the carbs? Are you giving it some throttle when you are trying to start it?


Sometimes a rag over the air box inlet can help draw fuel into the motor too.
 
hillsy said:
Have you accidentally turned the butterflies closed when you cleaned the carbs? Are you giving it some throttle when you are trying to start it?


Sometimes a rag over the air box inlet can help draw fuel into the motor too.
Click to expand...

The butterfly's are very close to being closed, should I turn up the idle a bit to increase the opening size?

And as for the air box, this may be really stupid, but we have had the front part off because its a pain to remove every time we have to get the carbs out, so there is a big gaping hole where the cover is supposed to go. Could this be causing the problem because there is no vacuum or suction to get the gas flowing?
 
Butterflies only need to be open a few thousandths of inch.
The further they ar closed the higher the depression through enrichener system
Blowing air through jets does not verify they are clean, it just means there is a hole that lets air move, it may be the wrong size hole
Pilot jets are only about 0.012"~0.018", reduce it by 0.002" and its a major reduction in fuel flow
Does it have air cut valves (transient enrichener system?)
Post a couple of pics of carbs.
Do you have service manual for it?
One thing that is an issues with all the 2 valve GS motors, exhaust valves too tight because people don't have shims changed.
clearance is only 0.001" to 0.003", always set exhausts as close as you can to 3 thou (it's really simple to change shims when you have the valve depressor)
Parts are easy to get hold of as it's same shim/adjuster tool as GS500 twin
 
I did the copper wire approach and cleaned out every jet and ole i could find, then ran carb cleaner through all the ports and jets, then used air.

Its just funny to me that it ran before we cleaned them and now it does run...

Im looking through the manual right now and reading up on all the trouble shooting for a non-starting bike.
 
Swivel said:
Telling yourself this over and over will not help get the bike running.
Click to expand...

Haha, yeah thats the message I have been getting.

Swivel said:
All this talk about vacuum is nonsense,really.It is not a crown vic.....
Click to expand...

I have read in the manual that if there is any sort of air leak that there could be "vacuum issues".

Also, one of the possible problems stated in the manual is that there could be a leak in the "vacuum gauge joint". Where is that?
 
http://www.motorcycleforum.com/showthread.php?t=102982

So this is my exact problem.

Seems like when he re-assembled the air box nice and tight it started. We have the air intakes open to atm. right now because the air box is suck a pain in the ass, but it looks like that might be our problem.

Gonna tighten up the air box securely and hope thats the problem.
 
The Japs have been setting up their carbs to run with airboxes for 30 years or more.

It still surprises me to see people throw the airbox away and then scratch their heads as to why their bike now runs like crap.
 
hillsy said:
The Japs have been setting up their carbs to run with airboxes for 30 years or more.

It still surprises me to see people throw the airbox away and then scratch their heads as to why their bike now runs like crap.
Click to expand...

All I can say is BINGO.

Put the air box back on nice and tight, close up the butterfly's just a hair....BRAP! Fired right up!

Got another runner in the shop 8)
 
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