An accidental discovery re O2 sensors

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Aussie Dave
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Year: 2017

An accidental discovery re O2 sensors

Post by Aussie Dave » Thu May 16, 2019 12:35 am

G'day all,

Re; O2 fuel dongles ...... I was testing my SDGT because it recently lost a significant amount of fuel economy and one of the options i tried was - Slip a washer under the O2 sensors :idea:

I had read on a car forum that mechanics often put a spacer under the O2 sensor to cure lean running, so when I took my fuel dongles off, I left the 12mm x 2mm copper washers in place when I refitted the O2 sensors. A good ride (200kms) through the hills and I thought the GT was as smooth as when I had the dongles fitted. I also thought the cat converter didn't get as hot at slow traffic revs..... but I'll retest that after I find the economy as returned to normal (I'm thinking it's stale fuel at servo's - so when I get a "fresh" tank of 95 octane and the GT yields it's normal economy, I'll have the opportunity to do more testing).

So, early days, but it looks like a 2mm washer under the O2 sensor has a similar effect as the O2 fuel dongles.

;)

PS I have no idea why this should work..... just had the thought bubble and tried it..... might all be a coincidence.... I will put the paper airfilter back in and run some injector clean to eliminate maintenance (GT has only 12,400kms up). Bike is running perfect, oil is fresh M5100 10w50..... our fuel price has recently been very high (for Aus) so I'm thinking car drivers are using more 91 or E10 94oct due lower prices, so the 95 stock has gone 'off' from low volume sales.
Current delights...1290GT-2017, CBR1100XX-2005

Prev loves...Capo1200TP-014, CBR11xx-002, 2xFZR1000genisis-94, FJ1200-89, FJ1100-84, XS1100P, VF1000F-83, CX500, VF750S, KZ1000J1-81, KZ1000ST-79, CB750F2-77, CB360T-74, CB175.. started it all in 1974 ;)

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Aussie Dave
990cc
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Posts: 827
Joined: Sat Mar 04, 2017 7:30 am
Country: Australia
City: Brisbane
Year: 2017

Re: An accidental discovery re O2 sensors

Post by Aussie Dave » Wed May 22, 2019 7:58 am

Here's a pic for info..... most have probably spent a fortune on dongles.... so this is probably only good info in case the dongles develop a fault or cause problems - so you don't need to buy or even spend time finding a new 330k or 1000k Ohm resistor for repair...... just shove some washers under the O2 probe & oem washer and install.

Also, I am reading on the KTM forum that there might be software upgrades being downloaded at service time as the factory finds a few tweaks to make things that bit nicer...... I haven't had a chance to verify this with my local KTM guys, but it sounds plausible. In any case my GT has always run nice, I only tried the fuel dongles because I could get them for under $50 and thought I'd try them for myself..... the 40T rear had the biggest effect for city traffic conditions - though the dongles reduced exhaust header temps (-30C) they increased the cat heat very noticeably....... a bit of a trade off that is not too hard to live with.
Copper washer under O2 sensor .jpg
Copper washer under O2 sensor .jpg (44.47 KiB) Viewed 411 times
I am about to re-test the oem closed loop system - on Tuesday I ran with full stock paper airfilter and O2 closed loop system...... next ride with Cu washer (it's about 1.5-2mm thick... whatever came with the O2 removal kit).

In full standard trim with some Caltex 95 octane fuel I got 17.5k/ltr dash readout on a 150km jaunt, and some minor drive sprocket jiggling in low speed traffic. The paper airfilter felt slightly more restrictive than I remembered for the K&N, so that will be the next stage of the test.

I have read (thanks DaveNZ) that the fuel dongles can carbon up the plugs, and my GT has had a year of garage starts only (while I was recovering from surgery) so I'll run some Valvoline Injector cleaner in the next tank of fuel to see if that was an issue........ :lol: ,though I mostly run above 4-4500 rpms (except slowing for red lights near home ;)), my GT has never been hard to ride..... it's just another V2 and likes the clutch pulled sooner than a 4cyl turbine.

12,600kms now..... that's 1,300km so far this autumn after that awful 2018 and a sweaty start to 2019 :roll: .

:mrgreen:
Current delights...1290GT-2017, CBR1100XX-2005

Prev loves...Capo1200TP-014, CBR11xx-002, 2xFZR1000genisis-94, FJ1200-89, FJ1100-84, XS1100P, VF1000F-83, CX500, VF750S, KZ1000J1-81, KZ1000ST-79, CB750F2-77, CB360T-74, CB175.. started it all in 1974 ;)

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Aussie Dave
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Re: An accidental discovery re O2 sensors

Post by Aussie Dave » Sun May 26, 2019 11:31 pm

OK, my fuel economy has returned to it's usual...... I get 20k/ltr in 5th at 100kph...... so it was most likely fuel, though I did run a half tank mix of injector cleaner on yesterday's 200km ride...... I still have the paper filter in with the Cu washers under the O2 sensors....... I retested the header temps Front was 143C Rear was 153C (on the insulation) so I guess they do richen up the afr's like the fuel dongles.

Maybe I'll install my K&N again when next on reserve fuel..... could try the dongles again, but my GT doesn't really need them with the Cu washers seeming to do the same thing...... :D
Current delights...1290GT-2017, CBR1100XX-2005

Prev loves...Capo1200TP-014, CBR11xx-002, 2xFZR1000genisis-94, FJ1200-89, FJ1100-84, XS1100P, VF1000F-83, CX500, VF750S, KZ1000J1-81, KZ1000ST-79, CB750F2-77, CB360T-74, CB175.. started it all in 1974 ;)

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