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SCORE!!!!!
by: rcq92130 - Jul 3, 2016 18:49:17 GMT -5
Post by rcq92130 on Jul 3, 2016 18:49:17 GMT -5
I'm just sayin ---- but the "retro" looks an awful lot like my scooter, a BMS Heritage. Parts easily available from BMS.
And if that's the case, Dan Martin discovered it's a Znen - better engine than others that come out of "The Land With That Already Has A Nice Wall 3,000 Miles Long".
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Post by rcq92130 on Jun 23, 2016 18:04:58 GMT -5
Was rummaging thru the garage, found an old volt meter, needle type. I could do an arch with O2 readout markings, and bend the needle for a perpendicular mount, mounting wouldn't be too difficult provided there's enough space under there. It's an old method to get a horizontal readout using a needle type gauge. Lots of fuel gauges used to use this mounting style, as well as older hi-fi equipment (that's high-fidelity for you youngsters). Would that be Amplitude or Frequency Modulation?  on that there hi-fi And then, just today, on a vintage movie site, I saw this:  |
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Post by rcq92130 on Jun 23, 2016 13:25:42 GMT -5
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Post by rcq92130 on Jun 22, 2016 21:52:05 GMT -5
That'l work. Just make sure it will read very low voltages. The sensor puts out between 0.2 volts (very lean) and 0.8 volts (very rich). I had trouble finding a cheat voltmeter that read tenths accurately (most seem to read something like "12.1 volts"), which is why I went with a f/a gauge. But a volt meter that has 2 decimal places will do just fine.
ps: I even have the guts of a brand new voltmeter (got it just for the can) - LED about 1/2 inch tall. Yours for free if you want it. But I think it only reads to 1 decimal place
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Post by rcq92130 on Jun 22, 2016 18:10:36 GMT -5
Yeah, yeah - you just want to make fun of the pimpmobile. Again. Anyway - took a video of the a/f gauge thinking ti would show how quickly it responds (much faster than the analog tach sitting to the left of it). This is with an old, used O2 sensor - one that was no longer good enough in my car to pass smog. But the car computer calculates 100's of times a second, and needs the sensor to respond fast. We only need it to respond in a 1/10th second. We want the engine to run "slightly" rich. I found the needle valve to be INCREDIBLY sensitive. Something like 1/16th turn would swing the gauge a LOT to either rich or lean. So, I think these gauges are pretty valuable for tuning. There is no way you could get anywhere near that close by ear. View My Video(I don't know why the TinyPic app makes the video all distorted like that. Anyway, I hope you get the gist of it.) |
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Post by rcq92130 on Jun 22, 2016 14:30:10 GMT -5
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Post by rcq92130 on Jun 22, 2016 12:49:10 GMT -5
Jerry If for some reason you wanted to buy a new O2 sensor, rather than just using a used one (some folks feel better spending more $$ !), this "manufacturer's closeout" from Rock Auto for $20 should work fine  You just want to make sure you don't get one of the new-fangled 'wideband' sensors, and want to make sure it's heated (4 wires, not only 1 or 2) |
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Post by rcq92130 on Jun 19, 2016 13:46:17 GMT -5
Particularly, P-Guy, Dan Martin, Jerry, George, and all others who shower their children in love !  |
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Post by rcq92130 on Jun 16, 2016 1:39:00 GMT -5
Yep.
There are only 2 generic forms of O2 sensors. The one i used was a discard from my BMW - it no longer switched fast enough to allow the engine computer to pass smog, but is blinding fast for our needs. Needle on the gauge fluctuates VERY fast to changes in throttle.
The one thing you need to avoid (with the gauge I showed) are "wideband sensors", the more modern kind that give output voltages ranging from a few tenths NEGATIVE volt to a few tenths positive, depending on the O2 content. These do NOT work properly with that kind of gauge.
The older, more traditional sensor (used on most cars up until 10 years ago or so, gave output from about 0.2 volts (super lean) to 0.8 volts (super rich). The meter properly and accurately interprets this signal. So - get a cheap, NON-wideband O2 sensor ... and get one that is used and considered no good for a car so the price is cheap or maybe even zero. Should work fine.
A note: sensors generally have 4 wires - 2 pairs. One pair is for the heater element (sensor needs to get hot). These connect to +12v and -12v, no particular order. The other pair is the sensor output you will connect to the gauge. The gauge I used had a +12v and a -12v wire (ground), and only 1 sensor output wire. So, I connected one sensor output wire to it and the other sensor output wire to ground.
It's very interesting to see air/fuel at mid-range, then WOT, then as the throttle is closed. I think with some thought you can really zone in on the best combination of low end jet - and mixture at idle thru mid range, and also main jet (for mid range and wot). You just need to ride, watch, and think through what is happening at different engine settings and what can move it all into a "slightly rich" result under all conditions.
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Post by rcq92130 on Jun 15, 2016 23:32:22 GMT -5
I know you saw this (b/c you wrote a response), but the second best thing I've ever done, scooter-wise, is put together a fuel-air mixture gauge. Without this you are literally just tuning with eyes closed. Even the best of ears makes this hard and inaccurate. If it were me .... with the top notch engine you now have .... I'd invest the $25, put together a gauge, and then tune accurately. Even if you then threw the contraption out it would be well worth it. Yours isn't any longer a lawnmower but a Caddy.
about 2/3 of the way down
ps: I've found I actually watch my gauge all the time, and find it very interesting to see what part of the RPM and torque range the engine runs lean or rich. It turns out to be a pretty complex issue.
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Post by rcq92130 on Jun 13, 2016 23:29:36 GMT -5
Way cool project!
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Post by rcq92130 on Jun 9, 2016 12:15:46 GMT -5
You just may be the very first person here who has thought of putting a SMALLER (i.e., LESS airflow, and thus LESS power) carb on their scooter!
If your idle mixture screw is that far out to get decent performance, it means you are running too lean. To fix this you put in a larger JET, not a smaller carb.
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Post by rcq92130 on Jun 4, 2016 17:08:04 GMT -5
I notice that Steve has not responded to anyone, and has not posted since April 22. Probably he got this resolved. At any rate, it's not easy to help without a response from the person you are trying to help.
Just saying, folks ..........
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Post by rcq92130 on May 27, 2016 19:34:41 GMT -5
When you do get around to firing this up, don't run it for more than a short, short time without the shroud around the cylinder head. As it is you have no air flow over the fins, and the thing will overheat in short order w/o the shroud.
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Post by rcq92130 on May 27, 2016 14:31:09 GMT -5
Blow harder?
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