Bogging between 1000-3000rpm

[DallasDude]

Got my carbs back after a professional ultrasonic clean and rebuild. I have the dynojet needles installed at clip 3 position in middle. I have the DJ94 size jets installed as recommended for using stock airbox and stock exhaust. The airbox has a uni filter in it all new and clean. I thought since the needles might run a little richer than stock then I would allow just a little more air. No vacuum leaks new rubber airbox boots everything is sealed up. I have to feather the throttle to get to 4000rpm and from there on it wakes up and can handle full throttle without bogging out. I did not drill out any holes in the carb as the dynojet manual says and just left that part alone. I’m trying to think if I’m lean or rich to make a bogging out between 1k-3k rpm’s. I’m rulling out dirty carb and vacuum leaks as that is not the issue. The one last thing I think that could be causing it is that I recently de rusted the tank and it’s now all grey inside and clean. After cleaning it I added gas with some two stroke oil in it not a lot to prevent flash rust after the tank cleaning. I know two stroke oil lowers octane so I went ahead and added 93 even though the bikes designed for 87 also I know the gas would sit a few weeks. It’s been about 3-4weeks and I’ve heard of stories of gas or octane going bad in 3 weeks time. My plan of action is to try to get through this tank of gas and refill with some fresh 87 gas soon to see if the problem goes away with different gas and no more two stroke oil in the gas. I’ll have to feather the clutch to engage at higher 4000rpm to avoid a stall out bogging and hopefully not burn out the clutch in one tank of fuel time. Also running slightly choked seems to help a little but not much so I’m thinking if it’s too much air. I really want to wait to see what happens after a new tank of gas though. Any ideas? Maybe go to notch 4 or 5 on the needle clip?

[DannoXYZ]

Try both #1 and #5 notch on needles and see which improves. Then you'll know for sure if it's too rich or lean.

If neither improves, then something else is wrong. Perhaps ignition. Make sure you're not using countrefeit spark plugs.

https://www.ngkntk.com/newsroom/blog/emea/fake-or-not/

ONLY use factory OEM parts! Especially electronics! So many crappy 3rd-party parts are bad right of box and needs to be tested to verify functionality before using. Here's guy that spent YEARS battling his mid-range surging problem. Was getting ready to put his bike up for sale. Turned out he had used non-OEM parts in his earlier desperate parts canon.

https://www.st-owners.com/forums/thr....177612/page-9

[DallasDude]

Well I went ahead and moved the clip down to position 4 and instead of putting two shims I put one only because 2 mysteriously disappeared after having my carbs rebuilt but no big deal just one shim would be a little richer than the dynojet manual. Well it turned out perfect. No hesitation through all the rpm’s to redline. It pulls harder than my previous Pregen ninja. It almost feels like it has the stock 14 45 gearing that’s how hard it pulls. It’s geared at 15 43 with a lighter tire 120 size. Anyone searching this looking for a perfect mild tune setup you can do one time and be finished with here it is. Factory airbox with uni filter inside. No holes in airbox. No snorkel removed. Factory exhaust. No baffles removed. Oem carbs. No holes drilled anywhere on the carbs (dynojet manual says to but I skipped that). DJ 94 main jets. Dynojet needles clip position 4 from top and only one shim not two. (Dynojet manual says 2) oem pilot jets. That’s it. Duplicate this setup you’ll be a first time go. Really impressed with how hard it pulls at 5000rpm. I remember my last Pregen pulling no where as hard at that rpm but it had oem needles.