Bad bogging after half throttle

[Guest]

I have a '77 GS750 running pods, straight pipes, jetted to 117.5 and air screws out just over 1.5 turns. Was running ok this morning but now it's bogging down really bad after about half throttle. Feels like it has about a third of its power. Figure it's a fuel mixture issue. I'm at about 1100 ft above sea level. Any ideas on what I need to adjust? Smaller mains, more air, less air, etc. Appreciate the help.

[mmattockx]

If you pull the choke while bogging what happens?


Mark

[R3lease1t]

If you pull the choke while bogging what happens?


Mark

If I pull the choke it seems to make it worse and start to sputter

[mmattockx]

If I pull the choke it seems to make it worse and start to sputter

Then you are rich. Does it clear out if you keep opening the throttle or stay the same no matter what? Does it pull through the bog in the lower gears but not the higher gears? If you are at 1/2 throttle (to really know put a piece of tape on the throttle housing and mark the throttle opening in 1/8 increments, then go test riding) then you are getting well onto the main jet and you will have to come down on its size.


Mark

[R3lease1t]

Then you are rich. Does it clear out if you keep opening the throttle or stay the same no matter what? Does it pull through the bog in the lower gears but not the higher gears? If you are at 1/2 throttle (to really know put a piece of tape on the throttle housing and mark the throttle opening in 1/8 increments, then go test riding) then you are getting well onto the main jet and you will have to come down on its size.


Mark

It pulls through but I don't have any power. I accelerate like I'm driving a 10 speed truck, not a 750 motorcycle. I might see if I can drop my mains. I talked to a mechanic who suggested I look into needle and air screw adjustment as well

[BurntKittyForge]

Might be a stupid suggestion, but I had that problem due to the fuel filter once.
Whenever I read a classified ad that states the bike bogs at highway speed I usually think it probably needs a new filter.

[Big T]

If it ran well before, it's probably not a fuel mixture issue, the mixture doesn't change overnight and become too rich
Maybe it's running on 3?
117.5 shouldn't be too rich

What do your spark plugs look like?
Where are your fuel screws set?

[chef1366]

Do you have a rusty tank?