GS Wont Run After Newb Jetted Carbs?

[Guest]

Bike tries to turn over and will go for a second with starter fluid. Checked to make sure the fuel lines weren't mixed up so expecting it should start right up. Any tips on where the air screws, pilot screws should be?


Trying to cafe a gs 750 bike so far have just jetted the carbs and put a 4 into 1 exhaust.
Looking for info to change lights and speedo.

[chuck hahn]

Well....seeeing that there were 750s with VM carbs and 750s with CV carbs, we need to know what year first.

[Prescot]

Sorry for the delay,
Its an 1981 GS.
Priming is fine, set to reserve, no vacuum line?

Thanks

[Steve]

Did the bike run (well) before the carbs were "jetted"?

What jetting changes were made?

Any changes to the intake side, or just the 4-into-1 on the exhaust side?

We can play "20 questions" all day long, but let's get a few of them answered at one time, instead of dragging it out.




It's like walking into a doctor's office and saying "I'm sick, please heal me."
The first thing the doctor is going to do is ask for symptoms and how long you have been experiencing them.

.

[Prescot]

image.jpgYes it started right up before. And didnt kill batteries trying that was last summer. Usally adjusting the air screw a little after warming up, now i dont even remember what position it was in. upgraded to the stage three kit. Pulled the air box and went with pods,got the small ones but now the carbs are uncovered until i can get it to idle.
Also added new levers clutch is wired, brake is not, and new regulator.

photo shows where needles sits now. Also tries plugging vent tubes didnt help.

idk might just see if i can get it to a shop.

[Prescot]

image.jpg

Had trouble finding new fuel line 3/8 so connected with this fitting, cc carbs, and a line connected to a vent on the gas tank? To a vent on the top air filter side of the carb rail behind the fuel intake which also might be backwards?

[Nessism]

Check the newbie mistakes thread linked in my signature to see if anything applies.

[Steve]

I see several things going on here. Any ONE of them is not going to keep the bike from running, but they are all ganging up on you.

Sorry for the delay, ...

You may have noticed by now that this is a QUICKLY-moving forum. Don't ask a question and come back tomorrow to see if anybody has seen your post. There have been times that we have had a couple dozen replies and settled the issue within an hour or two.

Its an 1981 GS.

Thank you. Now put that in a signature so we don't have to ask again.

Priming is fine, set to reserve, no vacuum line?

Without a vacuum line, it will only work in PRIme.

Yes it started right up before. And didnt kill batteries trying that was last summer.

And has the bike run (well) since then? I mean, ... have you ridden it or has it even left the garage?

Usally adjusting the air screw a little after warming up, now i dont even remember what position it was in.

First of all, you don't have "air screws". They adjust a MIXTURE, and the proper term (according to Suzuki and Mikuni) is "Pilot screw". You should not have to do any adjusting on them on any kind of regular basis. After cleaning/rebuilding the carbs, start with them about 3 full turns out (those are full 360-degree turns, not 'flips' of the screwdriver). After the bike is warm enough to run off-'choke', do a carb sync, then adjust the pilot screws for the best running mixture. After that, DON'T TOUCH THEM.

upgraded to the stage three kit.

Good to know, but only necessary if you have pods and a pipe.

Pulled the air box and went with pods,got the small ones but now the carbs are uncovered until i can get it to idle.

OK, now we know you have pods. Put them back on, you will be amazed at how much better the bike will run, even at idle. Sorry you settled for smaller (cheap?) pods, but it will work anyway.

Also added new levers clutch is wired, brake is not, and new regulator.

Not sure how you "wire a clutch", but none of those will keep the bike from starting.

photo shows where needles sits now.

On the contrary, it only shows that needles are installed. You can not determine from that photo where the height is set. If you have your Stage 3 kit installed, it should have told you which groove you put the clip in.

It might be the lighting, but it appears that the air jet (in the 8 o'clock position in the intake throat) might not be fully-seated. That should be SNUG in the carb body.

Also tries plugging vent tubes didnt help.

Plugging the vent tubes will NEVER help, not sure what you were trying to accomplish.

... idk might just see if i can get it to a shop.

Good luck with that. Your bike happens to be older than 10 years, many shop have a cut-off at that age. Your bike is probably older than most of the parts-changers that work there, many of them probably have never even seen a carburetor, let alone worked on one.

Had trouble finding new fuel line 3/8 so connected with this fitting,

The proper size fuel line is 7mm, which is smaller than 5/16", but larger than 1/4", DEFINITELY smaller than 3/8". Using the wrong size line and adapters is not helping anything.

cc carbs,

You "carbon copied" your carbs? What do YOU mean by "cc"?

and a line connected to a vent on the gas tank?

There is no "vent" line on the tank. There are three hoses connected to the tank. The larger one on the petcock is for fuel, it goes to the "T" in the center of the carb rack. The smaller one on the petcock is the vacuum line that turns on the petcock when the engine is running. It connects to a nipple on the engine side of #2 carb. The third line is a safety drain that goes to a catch funnel around the fuel level sending unit. It should be routed along the frame, behind the engine, where it will drain anything away from hot exhaust pipes.

To a vent on the top air filter side of the carb rail behind the fuel intake which also might be backwards?

My English teacher would have told me that this is not a complete sentence. I agree.

Check the newbie mistakes thread linked in my signature to see if anything applies.

I have a sneaking suspicion that pretty much all of them are hitting close to the bulls-eye here.

Sorry if this is sounding harsh, but you have asked for help, we are telling you like it is.

Where are you? There is a chance that a member might be close enough to help.
Please update your profile with a location and a signature that shows what bike you have.

.

[Prescot]

And has the bike run (well) since then? I mean, ... have you ridden it or has it even left the garage?

garaged

First of all, you don't have "air screws". They adjust a MIXTURE, and the proper term (according to Suzuki and Mikuni) is "Pilot screw". You should not have to do any adjusting on them on any kind of regular basis. After cleaning/rebuilding the carbs, start with them about 3 full turns out (those are full 360-degree turns, not 'flips' of the screwdriver). After the bike is warm enough to run off-'choke', do a carb sync, then adjust the pilot screws for the best running mixture. After that, DON'T TOUCH THEM.

intially reset at 3 turns out but after having trouble turned them all the way back in where they were?

OK, now we know you have pods. Put them back on, you will be amazed at how much better the bike will run, even at idle. Sorry you settled for smaller (cheap?) pods, but it will work anyway.

saw video mentioning to cut out the lining that seats the pod to intake side because it blocks vacuum port?

On the contrary, it only shows that needles are installed. You can not determine from that photo where the height is set. If you have your Stage 3 kit installed, it should have told you which groove you put the clip in.

started somewhere in the middle
It might be the lighting, but it appears that the air jet (in the 8 o'clock position in the intake throat) might not be fully-seated. That should be SNUG in the carb body.

Good luck with that. Your bike happens to be older than 10 years, many shop have a cut-off at that age. Your bike is probably older than most of the parts-changers that work there, many of them probably have never even seen a carburetor, let alone worked on one.

Yes there is a custom shop not too far from here but it could be "lots on money plus tax"

The proper size fuel line is 7mm, which is smaller than 5/16", but larger than 1/4", DEFINITELY smaller than 3/8". Using the wrong size line and adapters is not helping anything.

7mm line found on ebay

You "carbon copied" your carbs? What do YOU mean by "cc"?

error

There is no "vent" line on the tank. There are three hoses connected to the tank. The larger one on the petcock is for fuel, it goes to the "T" in the center of the carb rack. The smaller one on the petcock is the vacuum line that turns on the petcock when the engine is running. It connects to a nipple on the engine side of #2 carb. The third line is a safety drain that goes to a catch funnel around the fuel level sending unit. It should be routed along the frame, behind the engine, where it will drain anything away from hot exhaust pipes.

got it


My English teacher would have told me that this is not a complete sentence. I agree.

I have a sneaking suspicion that pretty much all of them are hitting close to the bulls-eye here.

Sorry if this is sounding harsh, but you have asked for help, we are telling you like it is.

Where are you? There is a chance that a member might be close enough to help.
Please update your profile with a location and a signature that shows what bike you have.

Best

Thanks, will give it another go.

[Prescot]

Does it matter if when drilling out the hole bigger here for the stage three kit, catching metal and leaving a gash or bigger than normal going to effect the perfomance, how?

thanks in advance