where to buy A/F ratio meter?

stormer94

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#1
Anybody own one or know of a good one to try that works for our applications on bikes? From what I've now been reading, it would be slick to monkey with to get your carb set spot on... at least for that days conditions. ;) I realize they are likely a few bucks and I'm not worried about that, although I'm hoping I don't need to drop a grand to get a good meter.

Thanks,
-Bob
 
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#2
K&N Engineering (The filter people) have them. They aren't expensive. www.knfilters.com/airfuelmonitors.htm
 

stormer94

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#3
Mainjet,

Thanks for the link. I don't know that it has the kind of range we need for 2 stroke bikes where 12.5 is optimal. Looks like 12.5 is the limit on the low side for the ones K&N shows. Hard to tell in the picture.
 
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#4
Two problems exist with the simple narrow band unheated sensors like the K&N uses.
Major Problem 1 is the standard narrow band oxygen sensor is designed for precision at 14.7:1 . There is a huge slope on either side of the sensor output once you move away from 14.7:1.
Problem 2 is temperature. The sensor output is temperature dependent and an unheated sensor like the K&N is dependent on the exhaust gas to keep it at the proper temp. It's a minor issue but still something to consider.

A good heated wideband oxygen sensor that will read accurately over the range racers are interested in costs upwards of $250, and that's without anything to read the output. I have one of the K&N type units sitting on the shelf. It's a fun toy, but nothing more. Haltech makes a reasonably affordable unit with a heated sensor, but you'll need a fairly stout battery to power the heating element. http://www.halmeter.com/Halmeter.imgs/Halmeter_AF30_Brochure.pdf
This unit is still subject to the slope issues inherent in narrow band sensors but the display does a better job of providing feedback.

Don't forget that lead and excessively rich mixtures will destroy the O2 sensor in short order.