Exhaust Sensors

[oldnortonrider]

?? Anybody, (?) have any advice or suggestions about
"which" one to use; "how" to use an emissions monitor .
.....(?) what results to maybe expect from one.
I see K&N shows that they've got one.
I know threre's others.
I'm curious to know if any of our members/or other have used
any kind of sensor/monitor, to check air/oxygen , emissions%, etc.
of these ratios, of the exhaust, before it gets to the muffler.
There's probably a thread on this somewhere.......

[Mike F]

I used one on my car on a few occasions but that worked ok because it only had one carb and one exhaust pipe. If you use it on the XS, you'll be trying to adjust two carbs at once without thinking off the problems of the balance pipe between the exhausts and also if your's has YICS. Probably better off using Colourtune.
By the way, I've just noticed that they've started selling the colourtunes in 4 packs - 1 per cylinder!

[oldnortonrider]

... check again .....?

......Each of my exhaust pipes has a hex head screw/bolt
screwing up into the pipe, before you get to the muffler.
I'm sure that's what they're for , >> (??) ; ..... ain't they ?
Whut else , could they be for .

Interesting news , about the Colortune .
I've always wanted to try it. ; I'll delve into it.

[Mike Hart]

a/f ratios

The hex taps on the individual pipes are where the factory set up the idle mix before capping it off, I'm guessing they used a special four-sensor setup with four readouts.

If you have a 4-into-1 exhaust, you can avoid the expensive K&N a/f rig - an inexpensive 2-wire (or 1-wire w/ ground) O2 sensor can be threaded into a bung in the collector after the four pipes join together. For a readout, Intellitronix (among others) makes relatively inexpensive LED units. (Summit Racing sells them)

For the electronically inclined, here is a schematic for DIY LED readout.

That 'solution' won't help you tune the idle screws though.

Also, a CO reading can be converted to an equivalent a/f ratio. The colourtune folks make one of those, I think. The drawback there is the lack of feedback under real-world operating conditions.

14.53:1 = 0.02% CO
14:1 = 1.00% CO
13:1 = 4.00% CO
12:1 = 6.60% CO
11:1 = 9.60% CO
10.7:1 = 10.00% CO

If the goal is to get all the jet/needle circuits operating properly together, it's hard to beat an on-board a/f display so you can see the effect of jetting/needle changes at all throttle positions and rpm ranges.

I suppose one could get two sensors and get/build two readouts for a 4-into-2 system...