high tech low budget carb tuning ?

o2 sensor
if this was put in one pipe at a time, and hooked to a 12 volt battery for the heater, the readings could be taken with a dc meter and the mixture set accordingly
it may be slow to respond because of the added volume, not too big a problem
cheap enough, universal o2 from ebay about 20$ and a few bucks for the rest
somebody tell me why it won't work, before i waste my time
don't laugh at my picture :lol:

 

Makes sense to me. I had thought of this before as a method of tuning.

I also found an air/fuel meter from Edelbrock (#6593?) that according to them only draws 1.5 amps maximum and could be run all the time. I thought of using it on each pipe through welded bungs for shop tuning, and then run it on the collector for regualr riding use.

If nothing else it would give a little bit of info if something changed from the norm. It obviously wouldn't tell you what cylinder was causing a problem if hooked into the collector but any change from the norm could bring you into the shop for a full test.

I also thought it would be great for my spontaneous trips to the mountains as I sometimes see quite an elevation change and it would be interesting to actually note a change.

 

I used to have a V-Max which had removable plugs in each header. I also had a SnapOn exhaust monitor but could never get it to work properly as I could not get the exhaust gases to flow very well through the inserted tube & along to the sensor.

Have found the Colortune plug to be easy to use, though not cheap.

 

EGT gauge from a wrecked aircraft with a four cylinder engine. Probably a bit pricey as I haven't been in the flying thing since the late seventies. I'd pick up a Trade-A-Plane and look around there. Should work great though.

Cheers,

Phil

 

Polock, I have something similar with an O2 sensor installed in the largest part of the 4-1 header and a LED display on the fairing. While it doesn't allow checking each cylinder one at a time if the combined reading looks good that's usually good enough except for adjusting the idle mixture and I use a Colortune for that since I don't have 8mm bolt holes in the pipes.

 

this is sounding like it might just work
i still have stock pipes with the bolt and i think their 8mm cause 6mm would have broke

Phil, you brought up EGT for in flight mixture control, this could be doable
i have a fluke meter with a temp probe, but where to set it ?
lean mixture would be max temp, not good, so if its backed off richer it's close but how much?
hows a pilot do it?

 

Hi Polok!

I enjoy your posts, very informative reading. They make me think.

I have been thinking about idle mixture and while you could use an EGT to tune it, (which was my original thought as it would be very precise) I'm not sure you could do anything else with it. A result of my overthinking everything. I was thinking of using it instead of a ColorTune plug. But it would be far more expensive. You would have a probe in each exhaust stack, so many inches from the port, all hooked to the gauge. Then you could just tune each cylinder to peak EGT plus or minus whatever you wanted, until they were all the same temp. Then, you would need quick disconnects so you wouldn't have all that wiring and meter on the bike. You could use it to make cruise settings but to do so would require rejetting the carbs to get the temp you wanted. Way too much work, and probably better ways of accomplishing the same thing.

In an airplane there are two ways of running mixture. But in an airplane you aren't concerned with idle mixture, mostly cruise power settings. The old practice was to set up the cruise power you wanted (RPM's and Manifold Pressure), and then set the mixture to peak temp and then back off a few degrees. Later practice was to go to peak and then go a few degrees lean of peak. I can't remember how many degrees but I'll see if I have any old aircraft manuals left so I can check. I've been away from flying since the late seventies and haven't kept up with it but from what I hear everything is computer controlled now. IE, you used to have a lever to control manifold pressure, a lever to control RPM's, and a lever to control mixture, for each engine. Now, you only have one lever per engine and the computer does everything else to make it work. Its called FADEC (Full Authority Digital Engine Control if memory serves, poor memory at that!).

Anyhow, the more I think about it it may be interesting to know what all the EGT's are in a bike engine, but from a practical view, what do you do with that information?

My old brain is too tired right now to think it through any further. Like I said, I tend to overthink everything. >)

More later,

Phil

 

Phill, don't go too far into it, i just want to set the idle mixture
really i don't know why i want to do that either, it idles fine now
but sometimes ya just have to know
the garage is a little tight right now but this is going to happen

 

ya know, you can just get a colortune plug for less than what you can build an O2 or EGT setup for. Especially if all you want it for is for the idle mixtures.

I just picked up one for $50 shipped. No backyard engineering required.

 

Hi Polok,

I know what you mean. There is so much stuff in my garage right now that I can hardly move around in it.

I also know what you mean about "sometimes ya just have to know". Sometimes I go to ungodly lengths to do just that. To the point of spending unholy amounts of money. But at least, when I'm done, I'll KNOW the answer. It can be quite satisfying can't it? >)

wink,

I have an Allison V1710 engine manual that, if I remember correctly, shows the color of various flames and the associated temperatures. The Colortune is a very valuable tool, one that is on my "to get" list, but it won't show you the temperature. This is all academic anyhow, unless you JUST HAVE TO KNOW, just to satisfy your curiosity.

Cheers,

Phil