86 FJ1200 Hanging Idle, Poor Off Idle Perf

[Prototype4342]

Hello all. So I finally got around to adjusting the valves on my FJ. Not too bad with the tool in all honesty. Sync'd the carbs and I'm trying to get them adjusted/tuned. The issue is it hangs up the idle when you do the blip the throttle test at around 2500 rpm. Tried adjusting around this [screws in to lean it out] but it doesn't seem to help. Also when I ride it it's pretty unhappy until you get up above 3000/3500 rpm or so. Do I need smaller pilot jets or am I doing something wrong?

[Bones]

Screw the mixture screws all the way in then back them out about 3 turns and try again. Turn the screws in or out about a quarter turn at a time while blipping, if it gets worse turning one way like bogging down, stop and turn the other way until you find a happy medium. If that doesn't fix it you might have a vacuum leak somewhere.

The screws on mine are about 3.5 turns out and runs well, but every bike will be different.

[FJmonkey]

Did you have this problem before you did the valves and balance?

[Firehawk068]

Usually a hanging idle means that it's already too lean.
By turning the screw further in, you are making it worse.

Bones gave some good advice.
Start with them all around 3 turns out, and see what that is like.

[Prototype4342]

Did you have this problem before you did the valves and balance?

Yes I did a bit. I also checked the intake boots and replaced the o-rings for them as well.

Usually a hanging idle means that it's already too lean.
By turning the screw further in, you are making it worse.

Bones gave some good advice.
Start with them all around 3 turns out, and see what that is like.

Screw the mixture screws all the way in then back them out about 3 turns and try again. Turn the screws in or out about a quarter turn at a time while blipping, if it gets worse turning one way like bogging down, stop and turn the other way until you find a happy medium. If that doesn't fix it you might have a vacuum leak somewhere.

The screws on mine are about 3.5 turns out and runs well, but every bike will be different.

Thanks I will try it. I should also mention I recently moved from Washington to New Mexico and about 2500 ft more of elevation. There is a chance I need new jets simply because of that

[FJmonkey]

Thanks I will try it. I should also mention I recently moved from Washington to New Mexico and about 2500 ft more of elevation. There is a chance I need new jets simply because of that

If you were set up lean (too much air in the Air/Fuel ratio) then that will reduce the problem a little bit. The higher elevation has slightly less Oxygen per volume of air. A 2500 foot rise from sea level has a 2% drop in Oxygen.

http://www.altitude.org/air_pressure.php

[Prototype4342]

So I got to where it seems pretty happy today. You guys were right and I was adjusting it backward [FJ tuning guide I read said if it hangs you are too rich] went out to 3.5-4 turns out and it idles good and doesn't hang up any more. Once I got it adjusted properly the idle I had it set at was at like 2500  so I dropped it back down to right around 1000/1200. Didn't get a chance to test ride it yet because I had to head to work but it felt much happier than it has since I got it. Will keep you all posted.

[Flynt]

A 2500 foot rise from sea level has a 2% drop in Oxygen...

Anyone riding near me at the RR smelled this in action.  Wizard is tuned well for sea level and 85 degrees.  The flatsides don't compensate for air density the way the stock carbs do, you have to adjust them and change jets if you want it perfect.  I choose the lazy path and run very rich in the winter and at altitude.

Today on the way home from work it was 87 degrees and Wizard was one happy machine.

Frank