Talked to my cousin about making a homemade AFR. He said pretty much the same thing that Teazer has stated. He said when he tunes a car or checks the mixture, he's looking for an ocsillating voltage. If the voltage is stead high or low, then the mixture is rich or lean. He said an oscillating voltage indicates a correct mixture.
He also said that you really need the sensor up by the exhaust port for an accurate reading as it needs sufficient flow past the sensor. The WEGO site talks abour reversion and shows an alternative hook up that adds a long length of flex tube to the end of the muffler. Obviously, this is not practical for a road going version, but would work on a dyno.
If you read thru the WEGO site, you'll notice that the reversion issue can cause you to get bad readings that would indicate a mixture richer than it actually is. That is reason for concern.
regards,
Rob
Kiss my Keyster (carb kit needles)Yep, I read that part, ......not that I especially wanted to see it, but there it was anyway.
Also need to be careful with any exhaust leaks that can introduce extra air and really throw it off. The bikes I plan on using it on have mufflers with baffles, which should help minimize the reversion effects. My Dream has the much maligned Apex mufflers, which are quite restrictive with stock, non-removable baffles. I have, however, poked a 5/8" or so hole thru the perpendicular baffle plate which should be just about right for the copper tubing for the sensor to slip right thru. It would be possible to run the tubing all the way up into the header if necessary. Not willing to give up just yet...maybe later? 66 dream, 78 cb750k, 02fz1, 09 wing
I had my fuel injected Harley dyno tuned by Fred Eno after putting a V&H exhaust on it, a Power Commander and a less restrictive air filter. He took a 1/4" rod with a point on it and after asking permission, poked a hole in the baffle of my muffler. He then stuck his exhaust gas probe about 24 inches or so into the exhaust. That was over 12K miles ago and she still runs like a raped ape.
regards, Rob A near perfectly tuned carb or FI bike is a joy to ride and definitely worth the effort.
Obviously what Hotshoe was doing that prompted this thread. It's a shame there's such a short supply of jets with the correct threads to choose from. I was able to get my carb model FZ1 just right with intake mods, jetting, and exhaust and the difference was night and day. Same with my FJR, except it took adjusting the ECM by trial and error, but worth it. 66 dream, 78 cb750k, 02fz1, 09 wing
The most useful tool described so far IMHO is Brewski's "TPS". I just use a white marker or paint on the throttle housing and on the grip.
"Oscillating voltage" indicates that the ECU is cycling either side of target A/F ratio. http://www.fuelairspark.com/Products/Do ... rgetaf.htm There's lots of talk about getting the A/F to a perfect 14.7:1, but we don't want 14.7:1. What we want is richer than that for full power and leaner for cruise. http://justskylines.com/knowledgebase/t ... ratio.aspx A good article here http://www.carcraft.com/techarticles/11 ... index.html Thanks for the good links, Teazer, the info is pretty consolidated there.
When I first started using the pin in throttle, I was amazed how much riding time was actually spent at such low throttle positions on the street. What I was guessing was 1/2 throttle or more was actually 1/4 or sometimes less. That makes the transitions from one circuit to another so critical to driveability. When I bought my first fuel injected car I soon took it back to the dealer and told them something was wrong. It was like the throttle was an on/off switch at lower rpms. Of course they told me it was just right and to get used to it. My Dream runs good, but I think it could be better. I think the idle circuit is a little rich, and the transition to needle circuit is lean. The Colortune confirms that, and I have done some adjusting, but always looking for that perfect state. 66 dream, 78 cb750k, 02fz1, 09 wing
No worries Brewski.
I remember years ago when a T100 was my only means of transportation and as I rode my 75 mile commute to work I tried a little exercise. I was riding at about half throttle at 60 or so and I backed out of the throttle and realized that I could ride at the same speed at about 1/4 throttle as long as I didn't have to pass a car or go up hill. I was amazed at how little throttle it took. The converse was that when the road opened up, I could get to say 100 on about half throttle and the next half made very little difference. The jetting was spot on but what I was learning was the importance of throttle control and of the lower end of the carburation range. When I started racing the throttle was more or less and on-off switch until I had problems on a part of Calder raceway where it stuttered and stumbled around one long critical corner. I made a few crude adjustments and all of a sudden I could shave seconds off my lap time because the bike was clean around that corner at part throttle and that allowed the bike to accelerate harder and cleaner down the main straight - which is where it was saving the time. Now I take "all" the race bikes I build and ride them fast and slow and make sure that off idle and mid throttle response is clean. I'm still learning but slowly working it out. I just wish I'd learned faster.
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