running rich and afr questions.

[kamkamdac]

sorry for the long post guys. got this bike a few years ago. 1990, 600cc, kerker exhaust, dynojet kit with 110 main jet installed (if i remember rite), clip position at 3 from top, and float hight at 16

wot @ >7.5k: 13.0 AFR
wot @ <7.0K: 12.8 AFR
cruising ~45mph: 12.8 AFR
cruising ~75mph: 13.0 AFR
idle: ~14.5 AFR

rides great at >3.8k rpm. pulls hard, good acceleration and engine runs smooth all the way to redline.

2.5k-3.5k runs ok. distinctive sound change in engine (sounds soggy) and a noticeable power drop but no bogging or complete loss of power. only notacable going up hill or under load.

idle-2k if i give it to much gas on take off and release the clutch to fast it will sometimes bog a little. when slowly driving up a steep hill (~15mph) if the rpms drop around 2.5k and i give it gas the bike will immediately bog then stall when i let off the gas. takes a few terns of the engine to turn it back on like its flooded. When the bike is bogging down afr is steady at 12.5. lowering float hight makes the problem allot worse, thats why there slightly out of spec.

Questions:
It seems to me that the main drooping down a main jet size would fix my low end richness, but I dont think its safe to go much higher that 13.0 AFR at wot. what do you guys think?
Ive heard that dynojet needles dont work in in our carbs for some reason. is this true and could it be causing my low end problems?
looking to possibly switch to factory pro kit, i noticed theres a 90-92 kit and a 93-97 kit. anyone know the difference?

[Kat-the-Ripper]

DO NOT LOWER YOUR MAIN SIZE! If anything you could go to a 112.5. My Katana/Bandit 1200 i run low 12 AFR. Dyno'd @ 145hp. with a smooth consistent band.

You are right about the DynoJet needles.....chuck em in the garbage!! factory pro makes a good kit....what stage are you looking for? What have you done to the engine to warrant a jet kit?

Before you scrap the DJ needles raise the clip 1 notch..(lower the needle) this will help with the bogging of the throttle.....but you will see the ARF lean out at cruising speed. This means your taper on the DJ needle is wrong, and that is why they need to be thrown out! This is just a little test for yourself so you know what your bike is doing.

Also what air filter are you running?

""Remember you can't believe everything on the net and alot of "carb settings" you hear about are situational and will not work for you. Or they are race settings which are crap for the street!""

[arsenic]

Factory Pro is superior to Dynojet, that is true. However, to say that "dynojet needles dont work in in our carbs", or being advised to "chuck em in the garbage". That's just ignorant. Are Dynojet needles the best option? No, but they work just fine. DJ just requires more trial and error than Factory Pro.

[kamkamdac]

thanks for the feed back, i appreciate it.

What have you done to the engine to warrant a jet kit?

full exhaust, stock air box and air filter.

Before you scrap the DJ needles raise the clip 1 notch

I tried that a few weeks ago and it did help the bog problem, but i noticed a dead spot in the throttle after making the adjustment. rite at the sweet spot around 1/4 throttle my afr gauge would go to >15 afr (which is its lean limit) and stay that way till i passed 7k. back off or give it a bit more throttle and the afr would drop back to normal. no noticeable power change though, would have never knew it was there if i didnt have an afr gauge.

with the needle clip back to the original position ive noticed the dead spot is still there but the throttle sweet spot is much smaller and harder to hit and i almost never hit it. even when i try to hit it it takes me a few tries.

thanks for the feed back guys. i think im going to stop trying to fine tune this thing and and start over with a factory pro kit.

any one know the difference between the 90-92 and the 93-97 kit?

[arsenic]

any one know the difference between the 90-92 and the 93-97 kit?

The Katana 90 and 91 600 had tappet shim valves, 8 lobes per cam. the 92-97 600 has tappet screw, 4 lobes per cam. Factory Pro has two different kits because the cams are different. However, the cams changed in 92, not 93. I just use the CRB-S22 (93-97) kit for everything 90-97. You're not going to notice any difference.

[92xjunker]

FYI you can have either shim or screw on a 92 600, change over stocked parts thing.

[arsenic]

FYI you can have either shim or screw on a 92 600, change over stocked parts thing.

I don't doubt that for a minute. I do believe the "official" change was technically in 1992, not 1993.