1980 GS1100LT Cleanup

[Guest]

I stumbled across this video of carb install....the fun starts around 20 minutes in
https://www.youtube.com/watch?v=cPKH4VGBkd4

 

[Guest]

Remaining parts I needed came in and I installed carbs yesterday but could not get my GS to start. I had an "IV" aux full tank set up with the tank slightly higher than what my gas tank would be.
1.) GS was running prior to working on it but was running roughly.
2.) Disassembled carbs, dipped in ultrasonic, simple green, and cleaned per the GS tutorials.
3.) I think the only thing I did not do from the tutorials was to check/reset float height.
4.) Installed new o rings and reassembled.
5.) Bench sync with a small wire and pilot screws were set to 2 1/2 turns (360 degrees) from lightly seated.
6.) Installed new spark plugs.
7.) Installed airbox and carbs. I did use my old boots which were still fairly soft. I'm certain that the carb/intake boots are sealed with no leaks and certain that the 2 outside carb to airbox boots are sealed with no air leaks....I think the 2 inside boots are sealing OK but not 100% sure.
8.) Air cleaner was installed prior to testing.
9.) Engine turns over fine but other than a backfire from exhaust the engine has not even fired/tried to start. I have OEM gas and vent hose and the vent is plugged...I checked it when turning over engine and there is good suction.
10.) After trying to start for some time I pulled the plugs and they were clean and dry. I checked the full level in aux tank and the level had dropped slightly.
11.) Tried several different pilot screw settings and didn't seem to make any changes and still got the loud backfire through exhaust.
12. Checked carb bowls by opening the carb drain slightly and they have gas.
13.) Pulled plugs again and they are still clean and dry so I added a small amount of gas into each cylinder but still will not even try to run. I pulled the plugs again and checked each one to make sure the are firing and yes they all spark. Plug wires should be correct with left coil going to 1-4 and right to 2-3.

I took a break and searched GS forum and saw that the popping when trying to start could be an exhaust leak. I have new donuts/seals in the exhaust and they looked good going into the engine but I did find a loose clamp on the exhaust pipe to muffler and tightened it up and the backfiring/popping pretty much stopped. The engine will just crank and crank with no hint of trying to start...as much as I hated to try, I even shot a little starting fluid in the airbox and still would not try to start. The choke and throttle cables seem to be functioning properly and pretty sure I have them set within recommended specs.

My plan for today was to do a little more research here and then work on my GS a little more this morning but like a dumba$$ I left the aux fuel tank hooked up to the carbs and looks like it drained about a quart of gas through the carbs and into the crank so looks like I'll be changing 3 day old Castrol oil first.

Any suggestions? I've had the carbs on and off enough times that I don't mind pulling them to check floats or any other parts.

 

[posplayr]

Congrats on getting this far. Check the timing (timing light or test light).
check coil voltage it needs to be over 11.0 v when cranking.
my gs1100ed would not start with only 10.5v till I did the coil relay mod even with new harness.
i know people will jump on this but shoot just a little starter fluid in a carb to make sure it is firing so you can rule out electrical. Do not do this repeatedly.

 

[Guest]

As a last resort I did try a shot of starting fluid and still would not fire or even hint that it was going to try and start. The plugs are all sparking when checked but the spark doesn’t seem real bright...daytime out though.

i am a novice mechanic but this just feels like some kind of electrical issue....is there any way that the kill switch can be stopping the engine from starting when it is in the run position?

 

[Nessism]

Bummer. You might want to check if the coils are hooked up right. Maybe 1-4 feed is switched with 2-3?

 

[Guest]

Bummer. You might want to check if the coils are hooked up right. Maybe 1-4 feed is switched with 2-3?

Put new oil in and switched coil to plug wires and she started right up.....left coil goes to 2 and 3.

time for some fine tuning now

 

[Guest]

Let my GS run about 2-3 minutes then shut it down to check for oil and gas leaks and all was good. I had to keep the choke slightly open or it would not idle but that was because I had my idler set too low.

After checking for leaks and problems I started my GS right up and adjusted idle and she ran fine with no choke for several minutes more. When I rev the rpms there is a slight “crack” noise from the exhaust but the throttle is very responsive and I’m surprised it sounds this good already. Pilot screws are back to 2.5 turns (360 degrees) out and I’ll fine tune in the morning when it is cooler.

I have a new petcock to install on the tank and after fine tuning I’ll add the tank but not going to get in a big hurry at this point.

Why would the coils be switched? I’m the original owner and have never had the coils replaced so it would of had to come from Suzuki like this.

 

[Nessism]

Only thing I can think of is the wires from the harness to the coils were switched for some reason. Did you disconnect them during the frame painting or other work

 

[Guest]

Only thing I can think of is the wires from the harness to the coils were switched for some reason. Did you disconnect them during the frame painting or other work

i never disconnected any of the main wiring harness....lights,horn, accessories was all. When I pulled the plug wires off I labeled each one of them and about 6-8 months ago when I was a little more informed on my GS I noticed that the numbers on my label didn’t match the manual but I just thought I somehow wrote down the wrong number on the label....I guess not now

 

[Guest]

Started my GS this morning (still on IV fuel supply)with the intention of adjusting carbs a little more but it was running and starting so well I left as is for now. Next I put the tank on, hooked up fuel and vacuum and hit the starter and she started right up and ran beautiful. I shut her down and installed the headlight fairing, side covers, and put several cable ties on the hoses and switch control cables on the handlebars. Dropped the hoist down and pushed her 15 feet out the door and set up on the kickstand and finally I was complete......turned the key on and hit the start button and nothing happened...gear sift indicator numbers are the only thing that works. No horn, turn signals, nada.....must be a dead short or bad ground somewhere and off comes the fairing, cable ties on bars, and tank.....looks like I’ll backtract all the progress from this morning

 

[Guest]

The problem didn't fix itself overnight so I first started checking for pinched wires since everything was working fine until I installed seat, fairing, cable ties, and wheeled out the door. The digital gear indicator was still the only thing working.

First thing I checked was the battery and ground is connected and this is a new battery and fully charged....should add that fuses were the first thing checked the previous day.

Didn't find any pinched wires so I removed the left and right horn/starter/turn signal controls and didn't see any problems with pinched wires and the contacts (which are new) looked to be working properly. I disconnected rear turn signals/brake light and still no power to anything else so I started removing all the cable ties and factory wire holders to expose connections better.

I had the key in the off position when pulling the electrical connections out for access...some I disconnected to expose easier but then re-connected after moving around. I also took the headlight loose for better access. Once I had most of the connections easy to get to I turned the key on and the digital gear indicator did not come on as before. I checked all the connections and everything seemed good so I tried to isolate the problem and disconnected the rear turn signals/brake light...still no change.
Somewhere around this time I pressed the horn button and digital gear indicator light came on but only when horn button was pressed....checked connections again and everything looked good so I pulled one horn connection loose, pressed horn button and gear light came on...pulled other horn wires off and no power to gear indicator.

In my limited electrical knowledge it looks like the horns are acting as the ground and since gear indicator light takes very little power to run it is the only thing that will "run"...

Any suggestions? I do not have a 12 volt circuit tester but probably should buy one to have around.

 

[Guest]

Any suggestions? I do not have a 12 volt circuit tester but probably should buy one to have around.

I'd start with that, or buying a test light so you can see where you have power and where you don't. No sense in asking for suggestions on where to start if you don't have the tools to do the diag suggested. Just sayin.

 

[Guest]

I did find my 12volt tester but didn’t need it. I was convinced there was a bad ground somewhere and I was looking for an excuse to tidy up my wiring anyway so I started at the handle bars and visually and physically checked every connection.....pulled most of the wiring away from the frame/side covers so I could easily access. I got all the way to the battery and there is one harness going towards the front/bars and there are 2 grounding eyelets coming off the harness....one eye goes to ground near the solenoid and the other eylet was broken off and not connected. I grounded/touched the eylet to the frame and everything worked. Still need to find out where it should be grounded but needed a break.
While the wiring is easy to get to I’m going to clean most of the connections and tidy up the wire routing....I’ll do a quick search and see what (if any) spray is recommended for wiring and connections.

I have learned to have a lot of patience from this and if I can rebuild carbs and trouble shoot electric issues then pretty much anyone can with the help from this forum.

edit: The ground that was disconnected should be grounded to my battery box...can’t believe I didn’t catch that sooner

 

[eil]

What a great thread! That bike is starting to look like a work of art. Glad to hear it's just about ready to hit the road.

I?ll do a quick search and see what (if any) spray is recommended for wiring and connections.

Spray the terminals with electronic contact cleaner and wipe them clean. Use compressed air or q-tip for the female connections. DeoxIT is widely regarded as the best brand but I would bet most any brand will work fine. I inherited a can of DeoxIT that's probably as old as I am, it still works great.

Make sure to work the terminals back and forth a little when plugging them back in. If any are loose, squeeze the female end slightly with pliers and try again.

Some people swear by dielectric grease but I find it just makes a mess when you go back to troubleshoot or repair something later.

 

[Guest]

Thanks eil!!

 

[Guest]

Got most everything back together this morning and all electrical is working as it should. There are several miles of good blacktop county roads by my house so I took her for a couple of mile road test with 45 mph top speed. Carbs are still set at 2.5 turns out and don't see any reason to make changes yet...idles and runs almost perfect.


I'll slap the headlight fairing on in a couple of days and then probably get licensed next week if all continues to go well.


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[jsandidge]

That sure is a beauty! If you ever want to sell that seat, let me know!

 

[Rob S.]

I love a happy ending!

That's 2 valves, correct? Do you know what the exact cc is, in the manual or stamped on the engine?

That seat, the white-lettered tires, etc., sure take me back.

 

[Guest]

That sure is a beauty! If you ever want to sell that seat

The seat was on her when I bought my GS and it was brand new on the showroom floor....don’t remember if it shipped to the dealer like that or they added the seat.....don’t think I’ll be parting with that seat anytime soon

 

[Guest]

I love a happy ending!

That's 2 valves, correct? Do you know what the exact cc is, in the manual or stamped on the engine?

That seat, the white-lettered tires, etc., sure take me back.

It is a 16 valve DOHC engine and not sure what the exact cc is....carbs and engine is stock.