Bogging in mid range

[Guest]

On my 1980 GS750E I put on K&N individual filters and jetted the carbs to stage 3. I also raised the needle and drilled the hole on the top of the slide. I then put in new NGK plugs gapped at 28.

At low RPMs it runs great and great power. When I get up to about 4000 RPMs I am noticing it is bogging. If I pull the choke about half way out it takes off.

Does this mean that I am not getting enough gas?

What can I do to correct this issue?


Thanks in advance,

2Stroke

[tkent02]

On my 1980 GS750E I put on K&N individual filters and jetted the carbs to stage 3. I also raised the needle and drilled the hole on the top of the slide. I then put in new NGK plugs gapped at 28.

At low RPMs it runs great and great power. When I get up to about 4000 RPMs I am noticing it is bogging. If I pull the choke about half way out it takes off.

Does this mean that I am not getting enough gas?

Yes

What can I do to correct this issue?

Give it more gas.

[2Stroke]

Hey Kent,

I just filled it up. (joking)

What I need to know is should I increase the jet size or raise the needle some more?

Thanks

[tkent02]

How much throttle was this bogging at?

Wide open go bigger main.

Part throttle, raise the needle.

[2Stroke]

It is on fairly rapid acceleration at mid range so I guess I will raise the needles.


Thanks,

2Stroke

[chef1366]

Stage three? Dynojet?

[2Stroke]

Stage three? Dynojet?

It was actually Six Sigma equivalent.

[tkent02]

Yeah you're on your own then. Bogging at 1/4 or 1/2 throttles is a needle thing. Bogging if you hold it wide open and that's a main jet thing. But really before you change anything spend some time reading, how to tune Mikunis is old stuff, the information is out there.

[2Stroke]

Thank you for the replies.

Tomorrow I am going to adjust the needles as see what happens.

I have also been reading about doing plug readings so I may do that as well.

2Stroke

[tkent02]

On BS carbs start with the main jet, get it right first as it effects the lower power mixtures too. Always perfect the main jet first on them. But really read about it first.

[2Stroke]

I have the CV carbs.

[tkent02]

Yes, Mikuni 32 BS carbs are the ones I'm talking about. CV carbs. Main jets first.

[2Stroke]

Ok

I got two larger jets when I ordered my Six Sigma kit because I told them I was planning on getting a pipe. I have not got that yet so at this point it is just individual air filters and the other adjustments I mentioned earlier.

Do you think I should go ahead and put in the larger mains and see if that takes care of the bogging?


Thanks,

2Stoke

[tkent02]

Yes, then fine tune the needle, pilot jet, and mixture screws.

Just follow Mikuni's procedure.

[2Stroke]

Ok

I will let you know how it goes.


Thanks,

2Stroke