Tuning my carb'd bike with a wideband?
 

Does this sound feasible to you guys?

I was thinking about using my wideband, which is currently installed in my car for tuning the carb on my GY6 scooter. (New 30mm hi performance carb)

I would install the wideband sensor on the scooter's exhaust, turn the key on in the car so the gauges will work, warm up the GY6 engine, and adjust the idle mixture on the scooter so that I will see 14.7 AFR on the car's gauge.
Then, I would do a steady state check on 2500, 5000 and 7000 rpm levels, and look for appropriate AFR numbers such as 14.7@2500, high 13s in the 5000, and 12s in the 7000 rpm range.
Finally, I would do acceleration tests to see enrichment.

It will involve getting a bung welded on the scooter's exhaust, but that's no big deal. I can cap it once I am done.

What do you think, good idea, or a waste of time?

Definitely worthwhile. I would use engine vacuum at idle, AFR elsewhere. Setting by engine vacuum at idle, you'll likely end up richer than stoich. Not familiar with that particular carb, but I assume you have a selection of jets, needles, springs, etc. (whatever it uses).

So, I should set idle mixture to best engine vacuum?

It'll give a really smooth idle.

Thanks a lot, Rick. I'll keep you posted.
I'm in the process of installing a big bore kit on my scooter these days.
(and props to you!)

I know when I looked into doing this on my atv (haven't gotten around to it yet) I read that the exhaust pulses out of a one cylinder engine tend to give erratic readings on WB sensors. I still want to give it a try though.

I tuned the idle on my pitbike with this method after installing a big carb.

Just stuck the o2 sensor in the end of the exhaust and tried to get close to 14:1. It was way off at first, but I didn't know if it was rich or lean. Stuck the wbO2 sensor in and then adjusted the idle jets from there.

Go for it...

Convert to EFI.

Having never tried it, I'd assume that placing the sensor as far forwards (away from the tailpipe) as possible might tend to protect it from this effect?

Or looking at it another way, is the muffler of a design that would permit the sensor to be installed in it, relying upon the muff to act as a sort of exhaust plenum?

https://www.miataturbo.net/attachmen...ine=1361222573


https://www.miataturbo.net/attachmen...ine=1361222573


https://www.miataturbo.net/attachmen...ine=1361222573


https://www.miataturbo.net/attachmen...ine=1361222573


https://www.miataturbo.net/attachmen...ine=1361222573

You know, I have been thinking about the EFI conversion.
I even sent an email to MBE for info.

It's just a bit tough to make that call right on the very cusp of the dreaded tax season.

I would hook the wideband up to a laptop and have it datalog while the laptop is in a backpack on your back.

I know somebody who has a little microsquirt kit hes going to put on an old Honda cingle cylider bike. Were planning on using bluetooth so we we can drive along with him and tune on the fly... you know, like a bawse.

Well, I contacted MBE, and pulled the trigger on the EFI kit!

I will break the engine in with the carb first in the name of dealing with one variable at a time.

I am building a frankenmanifold for the carb now.

A funny thing, that.

The picture I posted of the manifold was from a company that makes turn-key EFI kits for scooter engines. Here is a full image of the entire kit:

https://www.miataturbo.net/attachmen...ine=1361317008

Notice the little bluetooth module in the picture?

What's even scarier is that everything pictured in that kit costs only $403.16CAD.

They sell all sorts of tiny little injectors. This one is 38 grams/min, which translates to approximately 29 cc in our world:

https://www.miataturbo.net/attachmen...ine=1361317008



:bigtu:

Wow, man. I was actually joking when I first suggested it, but that's awesome!

Joe, the price is actually 299.98 CAD.

THAT's what got my finger itchy. (And my wife said I could...)

oh snap didn't think you'd just go ahead and pull the trigger.

this thread is about to get a whole lot more fun

Hmmmm . . . . I've got a carb'd quad that is kind of a pain in cold weather. Hmmmm . . . .

What type and what size engine?
Go for it, we could compare notes...

The base kit is $299. I added in the necessary options to make it equivalent to the kit shown in the picture, and arrived at $402.

I see a very small turbocharger in your future.

https://www.miataturbo.net/attachmen...ine=1361328152

This is the very same kit my neighbor (the guy Full_tilt is speaking of) has.

<- Has physically touched said big bore kit. I have been graced by coolness by association.

/bro's cool story