78 gs750: Where I'm at today

[Tryan31]

Hello all! So this is where I'm at with my new-to-me GS750. I've gone through BikeCliff's welcome maintenance deal and done everything I've been told and made sure not to make any of the top 10 newb mistakes.
New intake o-rings, new intake boots, valve clearance, cleaned air filter, sealed airbox, points timing, cleaned carbs with new o-rings and gaskets, and bench synched.
I bought these mufflers as the ones that came with didn't fit.

http://www.amazon.com/Bikers-Choice-Universal-Tapered-Muffler/dp/B000WKIC9O

They seem fine but are loose fitting but I do not think this is a cause for the problems I am having.
Jets: 105 main, 15 pilot. I installed +1 sized main jets to account for the new mufflers... Was that a good or bad idea?
SO... Carbs put back on, starts up 2nd or 3rd kick (since battery is totally dead, need a new one)... and this is where my problem starts. I can't adjust the idle screw to go below 1700-1800 rpms. Anything lower and the idle becomes boggy and eventually dies. I tried to tune the air mixture screw with the "highest idle" method, but can't seem to figure it out since I can't figure out my idling issue in the first place. Just for the hell of it, since I've never done it before, I tried synching the carbs with a vacuum tool. The levels were all way off and any adjustment I made sent my bike into a craze. Any slight adjustment to one carb and all four levels changed, or the bike died. I sat and experimented for a while with this. Any time I touched the slide assemblies, not even adjusting, just pushing down a little on any of them, the bike would bottom out or die unless I gave it a little throttle.

I think I am going to start over with cleaning the carbs. I want to somehow salvage the new o-rings so I don't have to order new ones. Do you think this is the best course of action? Or is there something going on that I am unaware of?

Thank you in advance for your help.
-TJ
:

[TheCafeKid]

Re-clean. It's not unheard of, nor shameful for a first timer to have to do it twice or even a third time until you know exactly what to look for and pay attention to.
I'd suggest making sure your pickup tube (the skinny brass tube that sticks out of the carb and goes into the float bowl) and the corresponding port in the float bowl are clear. A strand of copper wire works well for this, and spray cleaner into each port/jet passage and make sure the pattern coming out looks equal. Wear goggles/glasses. Some ports come right back around at your face..

[Tryan31]

Carbs re-done, gone through the works and everything looks good. Put back on the bike and it started right up but only lasted maybe a minute. When it died, I noticed carb #1 was flooded so I pulled the plugs and sure enough, they were wet. The vacuum line wasn't leaking gas, so I think my petcock is sound. My oil doesn't smell like gasoline, so that's good. I pulled all the plugs and let them dry out. Pulled the carbs back out to re-check the float measurements and made sure that needle wasn't sticking. Put it all back together and bike still won't start. Re-checked the points and they are sound. Could I be looking at an issue with receiving a good spark? I do not know how old these spark plugs are, but they do not look old. I'm thinking about buying new ones, just for the hell of it since I don't know where to go from here.
-TJ

[TheCafeKid]

So did you replace the battery? Kicking is great and all but with lights and ignition you still need a battery. Especially if your charging system isn't functioning as it should, which without the bike running its hard to fully test...

[terrylee]

Cafe kid is probably right may not be getting enough spark due to dead battery and trying to run lights, ect at same time. Replace battery, pull plugs and check each one for good blue spark (ground to engine). Go from there. Also did you bench sync the carbs, if not do that it will only help, then if you can keep it running do actually sync. with proper tool. terrylee

[Big T]

Plugs and points can look good and still fail

If you don't know exactly when the points, condensors and plugs were last replaced, replace them now. Even better, get a Dyna S

And get a battery

You need to know you have a good spark, good charging and the carbs cleaned

Also, as far as your tuning, what are the fuel and air screws set at?

[Tryan31]

New points, condensers, and now plugs and battery have been replaced.
Carbs cleaned and bench sync'd. Air and fuel screws turned to whatever was stated as a good starting point off of the rebuild guide on bikeCliff's site (I believe it was 1 1/4 turns out).
Strong spark from every new plug.
So... I got gas, I got spark, and bike turns over, but still won't start.


Noticed a small drop of fuel coming off of the bowl drain plugs on carbs #1 and #4.

I'M GOING BACKWARDS!! AAHHHH!!!!

[Big T]

Fuel screws should be less than 1 turn

Air screws about 1 1/2 turns

Do your fuel screws still have sharp tips? Tips broken off inside carbs?

All it takes is spark, fuel, air to run - I'm betting on fuel being the problem at this point

[ZakDanger]

Ain't it just the best? I have the same bike you do, been working on it for a bit now. Pretty sure my points need to be replaced, where did you get yers?

Also, the fuel pilots have flat tips on them, so they wouldn't have pointy ends. I thought I broke mine off at first.

[MisterCinders]

Ain't it just the best? I have the same bike you do, been working on it for a bit now. Pretty sure my points need to be replaced, where did you get yers?

Also, the fuel pilots have flat tips on them, so they wouldn't have pointy ends. I thought I broke mine off at first.

The pilot fuel screws are the sharp ones that go in the bottom of the carb. If yours are blunt, I too think you broke them off.

The pilot air screws are the flat tipped that go into the sides of the carbs.

If you are replacing points, the best place for new points is Z1. Pick up one of these:

http://www.z1enterprises.com/DynaS-Electronic-Ignition-DS31--Suzuki-GS-fours-with-KD-ignition-1308.aspx

or

http://www.z1enterprises.com/DynaS-Electronic-Ignition-DS32--Suzuki-GS-fours-with-ND-ignition-439.aspx

[ZakDanger]

Hm... yea yer right, I confused the air screw with the fuel screw