83 Suzuki GS750ES won't start after carb cleaning! Please help.

[stephendotexe]

I recently bought my first bike, an 83 Suzuki GS750ES. I love it! However, it sat for a few years and ran/idled pretty rough. I had to leave the choke open for awhile until it warmed up. The owner said I should clean the carburetor.

So that's what I did! I read the guides, took the carbs off and cleaned out the guk. There was a lot of goo in the pilot jet of one of the carbs, which was what I expected from the way it ran. After that I put it all back together being extra careful.

But now the bike won't start. It doesn't even start to catch. The engine turns over but there is no combustion. I worry that maybe I screwed in a jet too much or something of that sort.

Here's the things I checked:

• Battery is good and fully charged.
• There is fuel in the float. I unscrewed the float bowl and it dripped out. So the fuel system is good.
• The sparkplugs are good and sparking. Just checked them now.
• Everything was plugged back in properly.

The carbs are off again and I'm hoping to find out some adjustment I messed up. Do you guys have any ideas? I tried compression starting it and got nothing. I'm pretty sure there is a problem with the fuel mixtures but I'm not positive. I can't find any resources that tell me how much I should screw in each jet. I should have marked them but it's too late now. Doh!

Any advice you can give me is awesome. I'll probably have to take it to the shop but I don't have any regrets doing it myself. I learned so much about my bike and its carburetor. Should wished the dang thing worked

 

[Mr Toga]

Have you adjusted the valves?

 

[Ranger]

Did you set the float height?
Did you back the mixture screws out enough?
Do you have new o rings behind your intake boots?
Are you sure the fuel is fresh?
Did you dip your carbs or just spray them?
Are you getting spark?
Do you know how many volts your getting at the plugs?

Click search and find basscliff, then look at his signature and go to his website that has everything. I would post it for you but I'm on my phone.

Answer those, look at the site and we can help more.

 

[Mr Toga]

In case you wanted to research tonight: http://members.dslextreme.com/users/bikecliff/images/GSR_Greeting.html

 

[David_510]

YOu have the Cv carbs am i correct? Check your petcock. Make sure you hooked up your vacuum line. Make sure you have fuel in your floats. If you do then you need to clean your float needles. Clean them and re-try. If you have no gas in the bowls then your floats are plugged our your petcock is no good.

 

[Guest]

YOu have the Cv carbs am i correct? Check your petcock. Make sure you hooked up your vacuum line. Make sure you have fuel in your floats. If you do then you need to clean your float needles. Clean them and re-try. If you have no gas in the bowls then your floats are plugged our your petcock is no good.

Have you turned the fuel valve to prime? you may still not have enough fuel to start the bike, put fuel petcock in prim position for alittle bit then try . My guess if you did everything correct your bowls may have some gas just not full yet.

 

[stephendotexe]

Did you set the float height?
- I left the floats alone and was careful not to adjust them. They all looked uniform but I did not inspect them.

Did you back the mixture screws out enough?
- This I think is where I messed up. I turned the mixture screws so that they were snug, but I did not measure how tight they were originally. Should I screw them in all the way and then unscrew a 1/2 turn or something? This is where I was careless and I'm fairly certain where things went wrong.

Off of the website you recommended I found the manual for the Mikuni carb my bike has (http://www.mtsac.edu/~cliff/storage/gs/BS32SS_Carbs.pdf) but I can find the specific information regarding how tight to get the screws.

Do you have new o rings behind your intake boots?
-I didn't adjust these or take them off, so the original o rings are there. The seals inside were in great condition so I assume the o rings are the same?


Are you sure the fuel is fresh?
- Fresh, high octane fuel. I turned the tank to prime and let it drip in for a few hours before trying to start it.

Did you dip your carbs or just spray them?
- I took out the carburetor, opened it up, and dipped the jets into carb cleaner. I sprayed carb cleaner into the openings of other parts and used compressed air to push it out.

Are you getting spark? Do you know how many volts your getting at the plugs?
- Sparks are good. I don't know the voltage but I took off each one and tried it and there is a good, visible spark. I could check the voltage later

Any ideas?

 

[Ranger]

Turn those mixture screws 2 1/2 turns out from lightly seeded., 1/2 turn is wayyyyyy off. You won't even fire without a good enough mixture. I would guess this is your main problem but if it still refuses to start atleast we can eliminate problems easier.

After this you may want to pull your carbs off and just keep them on the rack and pull the float bowls off and measure the float height and will need to check your valve clearances.
All your jets will be screwed in until snug, the only one to adjust is the mixture screw on top of the carb body on the intake side.


So turn the screws out, try and fire it up and report back.

 

[SVSooke]

Down load this to http://www.mtsac.edu/~cliff/storage/gs/GS750E-ES_Shop_Manual_1983.pdf may answer more questions you have.

 

[Guest]

Did you dip your carbs or just spray them?
- I took out the carburetor, opened it up, and dipped the jets into carb cleaner. I sprayed carb cleaner into the openings of other parts and used compressed air to push it out.

If you didn't dip each carb body for 24 hrs then they likely aren't clean... didn't see where you replaced the o-rings either.

Basic maintenence needs to be done completely (no short cuts) or you'll just chase your tail around trying to troubleshoot your issues.

Valve adjustment & carb dip/rebuild with new o-rings will get you started.

http://www.cycleorings.com/

 

[stephendotexe]

Turn those mixture screws 2 1/2 turns out from lightly seeded., 1/2 turn is wayyyyyy off. You won't even fire without a good enough mixture. I would guess this is your main problem but if it still refuses to start atleast we can eliminate problems easier.

I'm a little new to this. When I said mixture screws I really meant the pilot, needle, and main jets -- all of the jets inside the carburetor. Anything inside the actual carburetor is screwed in snug. I didn't change the synchronize screw. Is the pilot screw the same thing as the pilot air jet? I did take that off and screw it in snug -- is that a problem?

Just to clarify, what needs to be turned back a few turns?

Sorry if what i say sounds confusing. This is the first time I've tried this and I'm doing my best to identify all of these parts. I didn't know to replace the o rings! Oops. I ordered a new set of o rings off that site and I'll put them on when they arrive but can that be the reason the bike suddenly won't start?

Thanks for all your help, guys!

 

[Ranger]

I'm a little new to this. When I said mixture screws I really meant the pilot, needle, and main jets -- all of the jets inside the carburetor. Anything inside the actual carburetor is screwed in snug. I didn't change the synchronize screw. Is the pilot screw the same thing as the pilot air jet? I did take that off and screw it in snug -- is that a problem?

Just to clarify, what needs to be turned back a few turns?

Sorry if what i say sounds confusing. This is the first time I've tried this and I'm doing my best to identify all of these parts. I didn't know to replace the o rings! Oops. I ordered a new set of o rings off that site and I'll put them on when they arrive but can that be the reason the bike suddenly won't start?

Thanks for all your help, guys!

Some people call it the pilot screw but it should be your mixture screw not the big idle one

It'll look like this but on the top of the carb where your airbox connects to the carbs. You have to take your tank off if its on the bike to get to them.

All the jets should be snug so if you did that your good, even the pilot next to the main.

As for the o rings, yes and no. It would run but it would run horribly and be leaking fuel and air within the body. The o rings behind the intake boots are important because you want a nice seal or you have an intake leak. You also wanna check your vaccum hose for any leaks.

Not sure if you did look at this yet but it tells you everything in order step by step pretty much http://www.mtsac.edu/~cliff/storage/gs/mc_maint/GS_CV_Carb_Cleaning_Series.pdf

Also put your bike info in your signature and your location in the top right. Go to USERCP and it'll say edit location, edit sig etc then it'll help out and someone might be near if needed.

 

[bluewool]

Follow the link Mr Toga left for you in post number 4. You can probably find a manula for a 750 in cliff's collection so at least you can straighten out the which carb parts are which.
The pilot screw is seated gently then turned out 2ish turns back depending on model etc..
When looking down at the carbs it's the screw at the front centre on the carb body, it is not the balance screw.

 

[BassCliff]

Greetings and Salutations!!

Greetings and Salutations!!

Hi Mr. stephendotexe,

In the links below you will find a couple of maintenance lists which are very important. It's very, very important to have properly cleaned carbs. Make sure there are no leaks in the air intake system (you might need new intake boots and intake boot O-rings). You'll also want to set the "idle mixture screws" according to the "highest idle method". Listen to the engine, it will tell you where they should be set. They should not be snugged up all the way. Start at 2.5-3 full turns out and adjust from there. All of the internal jets should be snugged up as there are no internal adjustments other than float height and perhaps needle shimming (if necessary). Float height is very important. Adjust them right in the middle of the spec range. Proper valve clearances are very important. Make sure the carbs are clean. Make sure the valves are properly adjusted. Then vacuum sync the carbs. Then set the idle mixture screws using the "highest idle method". You'll find many details on my little website. Let me share some GS lovin'.

I just stopped by to welcome you to the forum in my own, special way.

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", "Top 15 Tips For GS Happiness", the Carb Rebuild Series, and the Stator Papers. Now let me roll out the welcome mat for you...

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

 

[salty_monk]

It seems like it's carbs on this occasion but if you also washed the bike check the pipes aren't full of water... That can stop a perfectly good bike from starting... so I hear from a friend ahem

 

[stephendotexe]

The pilot screw is seated gently then turned out 2ish turns back depending on model etc..
When looking down at the carbs it's the screw at the front centre on the carb body, it is not the balance screw.

In that case I'm pretty certain I didn't remove that, which explains why I didn't see any o rings the first time. I'll double check when I get home to make sure though.

Just to verify, should this air jet be screwed in snugly or turned back?

 

[Ranger]

In that case I'm pretty certain I didn't remove that, which explains why I didn't see any o rings the first time. I'll double check when I get home to make sure though.

Just to verify, should this air jet be screwed in snugly or turned back?

Snug it up.

 

[stephendotexe]

Shoot. Well I'm out of ideas for now then. I think I'll pop it back on and try to start it one more time. If it still doesn't work I'll take it off, disassemble it, and do a complete dip and try again.

Thanks for all your help, guys. I'll give an update in a few weeks after its dipped and reinstalled.

(It's hard to go back to commuting by bus after I've had this baby)

 

[Ranger]

FEW WEEKS? No. Worst case you can get it fired up and rideable.

Had I still lived near you I'd just come up and help so I could mob up to Tiger and have fun along the 90 til Seattle in all the snow my lady says is up there right now . Theres some guys that live near you on here that may be able to help if you need a hand or a visual.

Just try what we've said, update on what its doing and go down the line. Shouldnt take but a hour or so to find the problem if you're updating us. I'll subscribe to this so it'll pop up for me whenever you update that way you can get a quick answer.

 

[jetta90]

Just out of curiosity .........when you cleaned the carbs out did you by chance open up the diaphram/needle portion of the carburators? You would access the diaphram of each carb by removing 4 screws found at the top of each carburator. Rubber diaphram and needle come out as a unit.
If you pulled these out and proceeded to disassemble the needle from the diaphram make sure you reassembled them with the tiny c-clip in the right groove on the needle!!

Heads up - some CV carbs from that era provide the option of several slots on the needle where the c-clip can be installed.............while some of these same CV carbs have only one slot. It had to do with emissions and the EPA.
The carbs off my 84 GS 750E came with the needles providing several slots (4 I think) on the needle......I'm also in Canada so the carb set up on Cda versus US models may differ.
Hope my ramble makes some sense.