question for you dyno boys, CO v Fuel/air ratio.

[eibargum]

i,ve had bikes dyno,d on dyno,s that use the fuel/air ratio metherd, and bikes dyno,d useing the CO coming out the pipe metherd, dont know if their comparable, but if you were getting 6% CO out of the pipe, what would that eqate to on the fuel/air ratio ie 11, 11.5, 12, 12.5, anybody used both during their working life as a dyno operater, or any amatuer,s out there that know .

[Diablo]

Sos I don't know the answer to that.

[drunkmunkey6969]

I've never looked into the comparison, because i've never needed to, but its certainly an interesting question......

Isn't CO more to do with emisions for MOTs n such to show engine wear, and A/F is obviously shows the ratio of burnt/unburnt gasses to help set carbs etc??

I could be completely wrong of course, as i just deal with Air-Fuel ratios on my dyno.......

[davidblythe]

dont chislespeed use co2 readings for setting up on their dyno the figure of 6% rings a bell

[Speed Demon]

As I understand it both give a clue to jetting but neither is entirely fallible. The main problem with most CO meters is a lag of several seconds in the reading so the run can be over by the time you see what the jetting was like at full bore, but having said that its just a matter of getting used to that as a tool - it worked fine for Taffspeed for years.

The advantage of fuel/air is that the readings can be 'live' and with most modern systems this means the jetting can be checked and even printed throughout the run.

As ever - the skill is all with the operator in interpreting the results and adjusting to suit. That is a steep learning curve.

[cezeta]

this may help

[cezeta]

actualy on its own i dont think it does, http://ega.bridgeanalyzers.com/document ... r%2017.pdf this is the full article

[sean brady scooters]

surely ........if you were to go by co readings alone..........they could vary maybe according to the amount of two stroke oil ratio used..........
on car engines say...........one that is new and efficient would produce low readings.......
but older cars....with worn bores/rings..........and burning a bit of oil would give high co readings..........
and so a scoot running say 2%............would differ from a scoot using 3or 4%.oil..................?
..........i suppose what i,m saying here is that if someone was to purely go by co readings...............on a scoot using 3 or 4 % mixture..............it would naturally read high.................and if the jetting was then leaned off to compensate.............it could only lead to disaster............

[drunkmunkey6969]

This is what we use:

http://www.airfuelmeter.com/french/lsu4_fr_sensor.htm

http://www.emissioncontrols.co.uk/page. ... %20sensors

http://www.mjpdyno.com/lambda.htm

[sean brady scooters]

thats good dan................baffle them with science.................