82 gs850g needs help

[Joeullmer]

I just got a 82 gs850g, gas was two years old. Drained, cleaned tank, refilled, and got two cylinders running... I'm 50 / 50 that carbs need to be rebuilt. Where should I buy, where should I not buy, carb rebuild kits? Bike has a Vance and Hines header, but still has stock airbox!!!???

[Rich82GS750TZ]

I think you’ll find your answers and some direction in the top 10 Newbie Mistakes thread. Linked in my signature.

[Brendan W]

Hi Joeuilmer and Welcome
Like Rich says. You have to be methodical and take it from the top. The chances of guessing the whole problem(s) on a machine of unknown history are slim.
That said, two cylinders not firing points strongly to an ignition issue like a bad supply to a coil.
The general consensus here is that carb rebuild kits suck. The link below is our library and has a lot of bought and paid for experience including carb rebuild tutorial and a source for the o-rings needed.

http://members.dslextreme.com/users/bikecliff/

[cowboyup3371]

Welcome Joe. I’m just down the street from you in Miamisburg while Steve, the resident whisperer, is in Centerville. Drop a line if you would like any help.

Carb rebuild kits are not the way to go. Pick up new orings from www.cycleorings.com instead, the owner is a member here, and new bowl gaskets from your favorite parts house. Grab a can of Berrymans carb cleaner and the instructions on Basscliff’s site.

[maisf]

Hi Joe,

I just bought a '79 GS850 about a month ago, I went through quite a few things. I had a case of no fire in cylinder 1-4 that was resolved by buying a new electronic ignition thingy from Dynatek.

Best advice I got since on the forum:
- go read BikeCliff's pages. All you will ever need is in there somewhere. Service manuals are there too.
- Read top 10 newbies errors. Most common failures on our bike is in there.

Haven't had much luck searching on the forum themselves. There's so many models of GS that it's like searching a needle in the ocean...

Here's what was my diagnostic:

- Remove gas tank
- Find the connectors going in the coils (mine had 2 oranges positives 12 volts and white on coil for cyl 1-4 and black on coil for cyl. 2-3)
- You should have nearly 12 volts between the oranges and the battery ground
- If not, un do all connectors, brush them, clean them with contact cleaner and replug. This include kill switch, key switch, connectors in the front light as the path of those oranges goes through it all. You'll likely find the wiring diagram for your bike in BikeCliff's.
- Then you have to test the ignition signal. The black and white on each coil has to go from nearly ground to nearly 12 volts at some point when you turn your crankshaft.
- Mine didn't had any voltage movement on the left coil so that was the culprit.
- You'll need to figured out how to change the ignition on your bike if it is what cooked. Mine had already a replaced electronic thing instead of the originals points.

Good luck and keep us informed!

Frank

[maisf]

Another thing is checking the coils:

- you should mesure around 4 Ohms between the orange and the black (or the white) going in the coils (this is the primary)
- You should have around 15 000 Ohms between the two spark plug boots of the same coil (left coil is cyl 1 and 4 / right coil is cyl 2 and 3) this is the secondary.

Anything else should read like an open circuit (infinite resistance).

If this read ok, your coils are likely doing fine.