carb/timing adjustment

[godrocksus1]

I have an 82 gs 850. It runs but I can't seem to get it right. I put a dyna ignition on it. I've synced and CLEANED the carbs. I think I need to run the air fuel screws in and back them out to what?? Also, the timing should be set to what. The marks make nooo sense!!

[BassCliff]

Hi Mr. godrocksus1,

Have a look at Mr. bwringer's excellent tutorials. Here is his guide for Where the ^%$#@! is TDC (Top Dead Center)? <<Click here.


Here are the specs for the 80-83 GS850 carbs:

Measurements = mm (in.)
Carburetor type = Mikuni BS32SS
Bore Size = 32 (1.26)
I.D. No. = 45110
Idle rpm = 1050 +/- 100rpm
Fuel Level = 5.0 +/- 0.5 (0.20 +/- 0.02)
Float Height = 22.4 +/- 1.0 (0.88 +/- 0.04)
Main Jet = #115
Main Air Jet = 1.7
Jet Needle = 5D50
Needle Jet = X-5
Pilot Jet = #40
Bypass = 1.0, 0.8, 0.8
Pilot Outlet = 0.7
Valve Seat = 2.0
Starter Jet = #32.5
Pilot Screw = Preset (actually, these can be adjusted - start with about 2 turns out from lightly seated)
Throttle cable play = 0.5-1.0 (0.02-0.04)

As you tighten the (pilot) mixture screws, don't run them all the way back in hard. You could break off the tips and that would be a bad thing. And now here is your very own magical, mystical, mythical, mind-expanding "mega-welcome"!

Here is your official "mega-welcome". Please take notice of the "Top 10 Common Issues", the Carb Rebuild Series, and the Stator Papers. Now let me roll out the welcome mat for you...

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

[Don-lo]

Did you replace the airbox and make sure it was sealed up properly? Did you run the Dyna ignition directly to the coils (bypassing the stock ignition wires)? 2-2.5 turns out should be good for the pilot screws. Ignition timing should make sense with a timing light. Do you have a mechanical advance? You may need that with Dyna S.

[godrocksus1]

yes the air box is stock. I bypassed all the stock ignition. set the scews to 2.5 turns. I payed a local shop to clean and sync the carbs. It was running pretty good but the other night I was heading down the highway and it loast about a quarter of its power. I limped home but it won't idle. It will start and run but the power isn't there. It won't Idle and when you hit the gas the rpms drop then pick up.

[BassCliff]

Hi Mr. godrocksus1,

I hate to say it, but if you paid someone to clean the carbs, it sounds like they didn't do such a great job. Or do you have rust or other debris in the gas tank? It doesn't take much to foul a carb. Did you check for spark on all four plugs?


Thank you for your indulgence,

BassCliff

[godrocksus1]

I had a guy tell me to put a good dose of marvel mystery oil in the tank, so i did. Could that be causing some of this?

[Colorado85gs550]

that marvel brakes up large chunks of stuff that may have been left in the tank and now you have run it through the carbs!!!!

[godrocksus1]

so... clean the carbs again?

[Colorado85gs550]

so... clean the carbs again?

yes.....and clean the tank and seal it!

[godrocksus1]

but but I don't wanna! again!

[Colorado85gs550]

its inevitable now

[godrocksus1]

So... is clean the carbs and seal the tank my best option and your best advice?