Did some carb tuning.

Robert Mose

Robert Mose

True Classic
I borrowed a friends wideband A/F meter today. Wow does this thing really take the guess work out of jet selection. It took about an hour and now the carb runs about 12.5 - 13.0: 1 under most conditions. The final jet selection for my 34 DMTR 53/250 carb is Mains 120/140 Air Corr 175/ 200 and Idle 50/50. It goes a little lean on the transition between the primary and secondary opening but I think I can solve this by changing the seconday Idle jet to a 75 or 100.
 
Which wideband A/F?

Robert Mose said:
I borrowed a friends wideband A/F meter today. Wow does this thing really take the guess work out of jet selection. It took about an hour and now the carb runs about 12.5 - 13.0: 1 under most conditions. The final jet selection for my 34 DMTR 53/250 carb is Mains 120/140 Air Corr 175/ 200 and Idle 50/50. It goes a little lean on the transition between the primary and secondary opening but I think I can solve this by changing the seconday Idle jet to a 75 or 100.
Click to expand...

nt
 
Ive given it back already and can't remember what brand it was. I was thinking of buying one but then figured $300 was too much for something you use once or twice in a lifetime. I might try to build one with some leds and a LM3914.


AFMeter.jpg
 
Robert... what do you estimate the cost...

... in parts to be?

Ya think Bob Brown has one built already from stuff he has laying around? I imagine the IC is the costliest part...
 
Tony,
The parts only cost about $10 plus whatever you spend on the O2 sensor and mounting hardware. The IC is only about $3.

Nick,
That looks interesting. I will keep it in mind.
 
Thanks Robert and Nick...

Looks like a great tool to have... much better than tuning by "ear", I would say.

I'm really not in the market to build to buy one at this time... but was just curious as to what the basic cost of the componants might be like.

As expected, the overall value is about 100 times greater than the sum of its parts.
 
I actually do have these parts

laying around. They amount to a couple bucks total. (literally!)
The only thing I'm missing is time lately. (on the road the past couple weeks)
Maybe for some Moxie... :D
 
Check out Innovate

Innovate sells one that you leave in the car. Comes with a gauge, sensor, bung, and harness. You can also datalog with it. You can find them for under $200.
 
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