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Discussion Starter · #1 ·
Picked up a Koso digital air\fuel ratio meter yesterday and got it installed today. got the brute warmed up and at idle it read between 14.7-15.1 went up and down between these numbers. so its pretty good i think 14.7 is the magical number i was told. when i give it enough throttle to open up the needles it runs real lean all the way up to 16.9 so i know i need to richen up the needles a bit. but when the needles kick in and it runs lean it takes a long time after letting off the throttle for the guage to drop back down to 14.7. the motor goes right back to idleing normally after you let off the throttle. is this normal with a mixture guage to take a while to drop back down or is something wrong. if you shut the bike off right after it drops back down to idle. and start it back up again it will go back to reading 14.7-15.1.

thanks in advance
 

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14.7 is chemically perfect but tuners shoot for 12.5 to 13 everywhere.

I like letting idle be low 12's to high 11's

You are going to get a high number on decel cause the exhaust is pulling air into the engine too.
 

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Discussion Starter · #3 ·
gonna see if i can get to at least 13. I installed #40 pilots and have the mixture screw out 3 1\4 turns and that was what i was getting 14- 15 with. might be able to go another half turn but not more then that. Is it normal for the meter to take a while to come down from decel. it takes about 5 minutes after you let off throttle before the meter reads what it was before it was given throttle.
 

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I am not familiar with that gauge the one we sell is instant, NGK.

Where did you mount the sensor bung?

If you need to turn your mixture screws out more than three turns you need larger pilot jet.

Always jet backwards

Get main right at wide open throttle, then to half throttle and set you needle height then do idle.

Idle really does not matter when you do it since does not affect much above idle.

Todd
 

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Discussion Starter · #5 ·
im not to impressed with this guage. do you have a link where i could look at the NGk one. i might take this one back since its not working
 

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Discussion Starter · #7 ·
talked to koso today and they told me the voltage has to be right on with no dips or spikes. so i put it on its own battery fully charged and it still didnt work like its supposed to. even if i start it with the chokes fully on and my hand over the snorkel with the engine spitting fuel out it still reads lean. weird anybody had this problem with one of these gauges before?
 

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Discussion Starter · #9 ·
gonna call them tommorow and see if i can return it and pay the diffrence on the wideband one
 

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I assumed it was a wide band.

Two requirements on a air/fuel ratio gauge is wide band and a heated sensor.

If not wide band it won't read outside a very narrow range and if not heated it takes about 45 min of run time to get the sensor hot enough to be accurate.

Sounds weird but true.

The NGK has both.
 
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