bogging down on top end?

[robgusto]

My 81 gs750 with pods has been rejetted. I went 2 sizes up on main jet to allow it to run richer. Since I went up the problem seems worse. When I'm toward the top RPM (can't tell for sure I don't have tac) the bike bogs down. It will actually accelerate a slight bit when I throttle back. So Im good through idle and mid range but I will bog down, then I let off throttle, the bike will bump forward a slight bit, then slow down. I know I read a post that that is indicative of where to look next for rejetting but can't find it. Any ideas?

[BassCliff]

Hi,

Have you done plug chops? What do the plugs look like? Most of the time a change to pod filters will require going up 4 or more sizes. Do you have a modified exhaust too? If so, add a couple more sizes. Do more plug chops and check the mixture.

For reference, I found these on some guy's website:

For CV Carb jetting, see the very informative article at Factory Pro. Also see the carb jetting tips at Motorcyclecarbs.com, Inc.



Thank you for your indulgence,

BassCliff

[robgusto]

Thanks for the quick reply! I am currently up 4 sizes on main jet and my dynojet kit only had my bike (with current config) up 2 sizes. I hesitate to go up more sizes as the condition seems to have gotten worse with the last upsize? I am still searching for the post that references the condition where the bike slightly accelerates after coming off throttle. I have not tried a plug chop but I will give it a try later this week. I have tweaked a lot but I'm going back to the dynojet kit recommended components and then will chop to see where I'm at.

[OldVet66]

That sounds like a lean condition gaining power when you roll off. I would run some plug chops so you would know exactly. Dynojet jets do not have the same numbering system as stock jets.

[MisterCinders]

Or his mains are too big making WOT rich and boggy. Easing the throttle puts it back to mid range before fouling the plugs. Do a WOT chop to be sure.

[Kaiser Sosei]

When it starts bogging down, hold the throttle steady and give it some choke. If it improves you're lean.

[chef1366]

Did you go up with mikuni jets or dj jets?

[robgusto]

They were Mikuni jets. Thanks for the replies! I was running lean..I replaced the (diaphram?)needles with slimmer ones and now I'm running perfectly. I just ran through all the gears on a test ride and was preparing to do a plug chop and choke test. I was sure that the needles would not fix the problem but they did and now just fine tuning. I have a colortune that I've been waiting to play with!!

[blowerbike]

They were Mikuni jets. Thanks for the replies! I was running lean..I replaced the (diaphram?)needles with slimmer ones and now I'm running perfectly. I just ran through all the gears on a test ride and was preparing to do a plug chop and choke test. I was sure that the needles would not fix the problem but they did and now just fine tuning. I have a colortune that I've been waiting to play with!!

so you installed a jet kit?