Need some Carb Advice

[RoZuki1100]

Hello everyone! Recently acquired a 82' GS1100GL, gorgeous bike! Well I've done a lot to the bike since I acquired it, I've done tank clean, carb clean, rebuilt the carb, cleaned airbox, new air filter, all the oils and brake fluids, new petcock, new fuel lines, new battery, and I'm running into issues tuning the carb. To begin I got the bike running on Saturday, 4/6 and she ran great for 20 mins, I rode her around great it just had starting problems because I drained the battery trying to start her. On the last 5 mins of that ride I got into 3rd gear and gave it throttle and she just bogged and had no response and had a little backfire, took her home threw her on the trickle charger and noted that all four pipes were hot and I would just check the carbs again on Sunday. Well Sunday comes around and I get the bike started and it has no power when in neutral and I give it a little throttle, rough idles like fluctuating up and down, and I noticed cylinder 2 and 3 are luke warm to the touch after idling for 10 mins while 1 and 4 are normal hot. Just looking for some advice, this is my first bike and its also the first real bike I've gotten the chance to tinker with and take apart and work on.

 

[Nessism]

Info in my signature can help you. Be sure to turn on the feature in your profile to view signatures, if you can't see the links.

Newbie Mistakes thread.

Carb rebuild thread.

New O-rings thread.

That said, be sure to check charging system voltage. Get a volt meter, set to DC volts, put a probe on + and -, and rev up the engine to 5000 rpm. You should see 14-14.5 VDC, if your charging system is working correctly.

 

[RoZuki1100]

The Links are on. Thanks Nessim. I'm going to check the voltage next, I ended up replacing all 4 spark plugs with new ones and all cylinders are firing. Silly me decided to do this last. Starts and Idles fine but as soon as you touch that throttle it goes to like 3k, 4k rpms and then nothing just bogs down, I've been adjusting my fuel/air mix with no avail. Tomorow I'm going to take the carbs off again and attempt to bench tune and set the mix. Unless someone can tell me if I'm doing something wrong or missing something but I'm going to keep tuning and trying until something good happens.

 

[Big T]

Read the carb rebuild tutorial Ed posted
If you didn't follow that, do so
Check the intake boots and replace those O rings
If it's not the carbs, it's the ignition.
The ignitor is a known failure point

 

[KiwiAlfa156]

...I noticed cylinder 2 and 3 are luke warm to the touch after idling for 10 mins while 1 and 4 are normal hot. Just looking for some advice, this is my first bike and its also the first real bike I've gotten the chance to tinker with and take apart and work on.

There's a huge clue. Before you pull your carbs off again, check the leads to the coils. The coil system is wasted spark with one of the coils firing 1 and 4 (approaching TDC with one cylinder on compression the other at the end of its exhaust stroke) and the other coil firing 2 and 3. With each coil firing 180? of crank rotation apart. So any issue effecting a pair of cylinders (1 and 4, or 2 and 3) ignition is your first port of call

The ignition runs like so: There is a signal generator with two poles 180? apart triggered by a magnet on the Automatic Timing Unit (ATU) on the LF end of the crank. The pulses are are used in a solid state "Ignitor" which in the early 80s Suzukis is in reality a glorified relay. 12V from the battery flows through the Ignitor to the coils and though to earth. Upon receiving a signal from the signal generator the Ignitor cuts the current to the appropriate coil, and the coil fires both plugs attached to it. If it were me I'd be checking all the connections to start with, and looking for broken wires or wires missing insultation, along this chain, especially the orange, and the black and white wires connecting to the spades on the coils.

If it is running only on two cylinders (possibly intermittently) you'll get a lot of the symptoms you describe.

 

[RoZuki1100]

Thanks Kiwi ill be checking all the wiring tonight after work, I did end up buying some new plugs because I swapped cylinder plug 1 into cylinder 2 and it began warming up right away. Definitely still having Fuel/Air mix issues but I know I just need to fine tune and sync them to fix that issue.