Laundry List GS850G

[Mr_Shake]

I recently traded a mountain bike for an '80 GS850G (great deal, I know!). It is pretty rough cosmetically, but runs. It has 45xxx miles indicated.
The PO put EMGO intake pods on it, as well as an unidentifiable 4-1 exhaust that is almost completely wide open, with a small hole in #3 header and one in exhaust pipe. I don't know whether it was rejetted or had valves checked, I doubt it, as the PO didn't seem to know much about bikes. It seeps oil from several gaskets.
I changed the oil with Castrol 10W-40 motorcycle, and changed the transmission and final oil with 85W hypoid oil. I couldn't find 90W ANYWHERE. I have a clymer manual that I have to change a fork seal and a few small fixes, I was just wondering what I should do to the old girl, and in what order. It runs a little rough till it is warm, and it pops in the exhaust whenever you let off the gas. I haven't done plug tests yet, mainly because I don't feel comfortable at full throttle on it yet! I'm a newb, I know. I am mechanically able, just inexperienced with engine work. Any advice would be great, Thanks!!!

[Nessism]

The bike is not going to run right until you rejet the carbs - the pods and header flow more air than stock. Dynojet kit is the easy way out http://www.dynojet.com/pdf/3306.pdf

[Mr_Shake]

Ya I figured on that, plus how difficult is valve check?

[Smokinapankake]

Valve check is super easy, but plan on replacing the valve cover gasket if you're in there. Your clymer manual should be able to walk you through this. I'd never done it before until I bought my old dinosaur and I was surprised how easy they are. Also be sure to check cam chain pin to pin length while you have the valve cover off. Your Clymer manual should tell you what this distance should be (between 20 pins or something if I remember correctly).
If you have a multimeter I suggest you read the stator papers found elsewhere and perform those tests as well. Get a good idea where she is and then you'll know better where to begin.
Welcome aboard!!

[Nessism]

Ya I figured on that, plus how difficult is valve check?

Do a search on valve adjust by the author BassCliff. He put together a first rate tutorial that will walk you through the steps. I love this forum but the admin is pretty lame about putting up stickys or loading The Garage with worthwhile stuff like this tutorial thus you have to search.

[Road_Clam]

I recently traded a mountain bike for an '80 GS850G (great deal, I know!). It is pretty rough cosmetically, but runs. It has 45xxx miles indicated.
The PO put EMGO intake pods on it, as well as an unidentifiable 4-1 exhaust that is almost completely wide open, with a small hole in #3 header and one in exhaust pipe. I don't know whether it was rejetted or had valves checked, I doubt it, as the PO didn't seem to know much about bikes. It seeps oil from several gaskets.
I changed the oil with Castrol 10W-40 motorcycle, and changed the transmission and final oil with 85W hypoid oil. I couldn't find 90W ANYWHERE. I have a clymer manual that I have to change a fork seal and a few small fixes, I was just wondering what I should do to the old girl, and in what order. It runs a little rough till it is warm, and it pops in the exhaust whenever you let off the gas. I haven't done plug tests yet, mainly because I don't feel comfortable at full throttle on it yet! I'm a newb, I know. I am mechanically able, just inexperienced with engine work. Any advice would be great, Thanks!!!

Dirty carbs, and 25+ year old GS engine gaskets. The #1 and #2 $$ frustrations $$ on GS (or any) 25+ year old bike. The decell exhaust poping is either a badly rotted exhaust sucking air, or bad exhaust gaskets sucking air. Pick your topic, use the search feature and you will archive a years' worth of reading and knowledge on these exact issues. Oh yea, and read the "Stator Pages" in the garage.......