Dynojet A/F Meter

brewsky · Post by **brewsky** » Thu Apr 07, 2011 5:25 am

Jensen,
The reason I asked so many questions about dyno operation is so the next time I go, I want to be able to tell the operator what I want.

The fact that he told me the RPM readings were "about 1,000 RPM off" the last time I went didn't sound right to me, and the curves that resulted were obviously incorrect.

Remember this thread?
http://www.honda305.com/forums/viewtopi ... light=dyno

The module I just purchased should allow me to post A/F vs RPM over some period of time, but since there is no TPS signal to input, I will have to rely on visual info and try to overlay it if possible.

Most importantly for me, I will be able to watch the A/F readings as I feel the engine respond to on road conditions.

I will post any results when available.

jensen · Post by **jensen** » Thu Apr 07, 2011 7:20 am

Hi Brewsky,

I know, that why I mentioned it :

The other thing is that I’m interested in what other bikes look like on the dyno, because now, I have only my bikes as a reference. I have never seen any other dyno chart of a standard CB72 or a CB450 K0, or a CB400F, not on this forum, and not on other forums. The only curve I can compare is the dream, but I guess something went wrong while measuring.

Jensen

brewsky · Post by **brewsky** » Fri Apr 08, 2011 7:26 pm

Work in progress......don't laugh, it's all temporary, then on to another bike.
Decided against riding down the road with a bunch of wires hanging out of the tailpipe, so a trip to the local muffler man netted a bung, plug and weld-in job for $10.00.

brewsky · Post by **brewsky** » Mon Apr 11, 2011 7:01 pm

Stage 1:
Got the meter operational (no RPM read or Data Logging hooked up yet).

Haven't had a chance to road test, or even check for exhaust leaks yet either.

I installed a cut out switch for the headlight, so I could run full magneto power (Ig Switch on lights position) and turn the HL off, and run the meter, box and heated sensor off the HL circuit.
I was going to do this anyway, since the dimmer switch has no middle "off" position on mine.

Pics:

brewsky · Post by **brewsky** » Tue Apr 12, 2011 5:14 am

Video Links:
http://s193.photobucket.com/albums/z313 ... 77Idle.mp4
http://s193.photobucket.com/albums/z313 ... V00451.mp4

brewsky · Post by **brewsky** » Tue Apr 19, 2011 6:55 pm

Finally got a chance for the first road test today.
Some initial observations:

Steady state idle........11.5 A/F ratio

Just off idle to 1/4 throttle jumped around from 11 to 13.5

Steady uphill load, steady speed:
1/2 throttle............11.5
3/4 throttle............12.5
wot.......................11.5

It was also interesting that under steady load, wot, A/F, as the bike slowly increased RPM, got leaner with RPM increase.

Also, on decel the A/F really got leaner. but rarely past 16.0.

These numbers are from memory, so are subject to verification.

teazer · Post by **teazer** » Wed Apr 20, 2011 12:51 am

Fascinating results. 12.6 is max power as a rule. The bike is generally rich but leans out as you crack the throttle and is perfect for power at 3/4 and too rich on the main jet alone but getting leaner as it revs up.

What happens to A:F and performance if you screw the air screw out slightly say 1/4 to 1/2 turn?

And with one size smaller main jet and the needle raised one clip position?