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Hi, Anonymous it should be noted that the "AIR FUEL" mixture screw adjustment "ONLY" manages your idle and has no effect on any other circuit also any intake leaks must be repaired before the A/F adjustment procedure can be performed otherwise you will never obtain a proper idle and you will waste a lot of time chasing the impossible. The A/F mixture screw's purpose is to fine tune the fuel charge entering the combustion chamber. The following applies to both 2 and 4 stroke engines:
1. The mixture screw may be sealed at the factory with a Welch Plug please review the following video for removal. https://www.youtube.com/watch?v=wAXcksgvDkM
2. The mixture screw manages a range of 3 complete 360-degree counterclockwise turns from the bottom/closed position.
3. The mixture screw should have a spring and o-ring for tension and sealing integrity.
4. Turn the mixture screw clockwise until it gently bottoms out, this makes the fuel charge very lean and the engine should not idle if it does then the pilot/idle jet is too big and needs to be replaced with the next size smaller.
5. Turn the mixture screw 1 and 1/2 turns counterclockwise to establish a baseline for starting the engine.
6. To fine-tune the idle circuit, adjust the mixture screw 1/4 turn in or out to achieve maximum idle RPM, wait 15 seconds between each adjustment for the idle to settle.
7. Never go past 3 full turns out this will make the fuel charge rich, foul plugs, and produce black smoke out of the exhaust, if the engine RPM keeps increasing past 3 turns the pilot/idle jet is too small and needs to be replaced with the next size larger.
8. After achieving maximum idle back out the mixture screw another 1/8 of a turn then adjust the throttle cable idle stop screw to 950-1050 RPM.
9. This procedure works great on 99% of all engines, for the 1% that demand a more robust throttle response on aftermarket monster fuel delivery systems additional tweaking outside the box may be necessary.
For more information about your issue and valuable "FREE" downloads that you will need for viewing or printing please click on the blue links below. Good luck and have a wonderful day. Need carb help rough rich Suzuki 800 Adjusting the pilot jets in the carbs 1998 Suzuki Intruder 1500 SUZUKI VZ800 Manual OEM parts for Suzuki http://mybikemanuals.com/suzuki
Here is specs for those carbs
- AISAN AS27VW
I.D. No. - 04A10
Bore - 27 mm
Idle r/min - 1300+/-100 r/min.
Fuel level - 9.0+/-0.5 mm
Float height - 20.5+/-1.0 mm
Main jet - #94
Main air jet - 1.2 mm
Jet needle - 5B10-3rd
Needle jet - 2.60 mm
Throtlle valve - 11.0
Pilot jet - #34
By-pass - 0.8,0.8,0.8 mm
Pilot outlet - 10.8 mm
Valve seat - 2.5 mm
Starter jet - GS1 #60, GS2 #54
Pilot screw - PRE-SET (2 turn out)
Pilot air jet - 1.35 mm
Throttle cable play - 0.5 - 1.0 mm
Choke cable play - 0.5 - 1.0 mm
Sounds like you have a clogged pilot jet in the front carburator. Have the dealer remove the pilot jet and clean it. They can also adjust the pilot fuel mixture and synchronize the carburators to make it run properly. If they can not do that, you should find another shop.
Sounds like a lean condition. Particularly a transition from a lesser jet to the main jet in the carbs.
Depending on how severe the problem is it could be as simple as adjusting the the main jet needles and synchronizing the carbs and richening up the idle air screw a bit.
Remember that all general service basics should be checked before adjusting carbs. Valve clearence, spark plugs, air filter, cam chain tension, etc. should all be checked/ adjusted/ serviced/ replaced before adjusting a carb.
122 outer and 125 inner main jets, 3rd clip from the top on all needles and from 2 to 3 rounds out on the pilots should give you a good mixture setting. Adjust pilots as needed for smooth idle and to allow for any intake or exhaust mods. Good luck...i hope this helps.
you don't! set pilot two turns out from fully in on carb pilot jet, start engine and set throttle adjuster screw on carb to fast tick over, adjust pilot to get even firing and readjust throttle screw to @1000rpm
You should be able to drill out the A/F caps on the mixture screws if they are still in place. It sounds like you still have a blocked pilot jet circuit though if it runs well at higher revs when the main jet takes over.
No one can tell you what jet size to use unless they know exactly what exhaust and jets you have now. The best thing for you to do is go back to a known good configuration. If it has never run right since you had it, go back to stock (make sure it runs right with stock settings now!) and start your adjustments from there. Change one thing at a time and do performance testing between each change. Dyno runs are best, but timed runs might work too, depending on your application.