the "oh so tricky mid range"

[stockGS]

Alright, I am going to try and trouble shoot my mid range problems and I wanted to start this post to track my progress. Also, to bounce ideas off the group and take suggestions.

My issue is a choppy ride at 55 to 60, running at 4k to 5k rpm. I have looked up this issue on the forum and have read a ton of different solutions and I plan on going through them till I find the right one for my bike. The back ground is this, I have cleaned the carbs fully twice in 1k miles. I had a pinched vent hose and was hoping that was it. No such luck. So on to the next. I know float height and needle height can solve this issue. I was going to try float height first as it makes more sense to me. I read to raise the float height for better suction, is that right? Will that help smooth out the mid range?

[tkent02]

I read to raise the float height for better suction, is that right?

Umm, no.

If it were me, would get every single adjustment on the entire engine perfect before I stated changing things you don't understand.

[tom203]

Your post title says it all; to get the mid range running right, lots of things have to be correct as bike transitions off idle circuit to main circuit. You cleaned carbs-the proper way? Have you reviewed Mr. bwringer's issues on this link...... lots of items come into play

http://members.dslextreme.com/users/bikecliff/images/GSR_Greeting.html

[boingk]

Hi there mate, for any tech info like this we'll need a detailed setup of your bike to give any relevant info. I'll give my last GS850 as an example:

*****

1984 GS850
Stock engine
Valves set to factory
Oil and filters service 2k ago
Running pods and 4-1 exhaust
Running Mikuni #125 mainjets and 2.25 airscrew settings
No air, oil or fuel leaks anywhere.

Then give a description of your problem, eg I have great acceleration from 2000rpm upwards but tend to pop a lot on deceleration.... whats wrong?

Answer: You may need to up your mainjet, as if its fine everywhere else you are running lean up top. Try 130's.

Fix: I put in 130's. It solved the issue.

*****

Note that in the example above all other considerations were taken care of - the bike was well serviced and there were no fuel or air leaks anywhere. You need to rule those out.

After that, you may need to get a more thorough description of the problem. Is it midrange everywhere, any gear? What is throttle response like? Does it have a good, solid idle? What is your acceleration and topend like?

If it has a hanging idle and weak topend then you are most likely lean and need to tweak both mainjet and airscrew settings.

Cheers - boingk

[stockGS]

Good call boingk. Tkent02, the needle height is one I don't get at this point. Everything else I can wrap my brain around. Though I would hate to buy new jets as an experiment, so I would like to try everything else first.

I have a straight stock set up on a 1982 GS850G.

Stock air box
Stock exhaust
Jets are 115 (biggest, main?) 40 (under the rubber cap) 180 (air jet)
Air/fuel screws are set at 3 turns out.
Oil changed 1400 miles ago
Sprayed starter fluid around all 8 boots and no air leaks, engine is tight.
Idle is a smooth 1k, with a good throttle response.
Start up is fine, acceleration is strong in any gear. Top end is smooth.

I seam to have problems at cruising in any gear. When accelerating I have no issues, but when holding the throttle at 1/4 turn is where it gets choppy. I also smell gas in the exhaust and I have backfire on warm up and compression braking. That's a sign I am running rich right?

Thanks for the direction.

[stockGS]

Oh, and I have done a complete tear down with a 24 hour dip for each carb. New rubber throught out the carbs. Floats are set to 22.4m.

[xxBenJamminxx]

Have you tried plug chops with some new plugs after riding at that speed making it feel choppy for a couple miles, then pull in clutch and hit kill switch immediately? Then just pull right over and pull ALL the plugs to get a good reading on each one. At least that would give you a starting point to know whether you need to lean it out or richen it up where the problem lies.