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Tuning the Fat Duc on GT1000

9767 Views 18 Replies 14 Participants Last post by jlduck, Jul 27, 2015

bmwson

Discussion Starter · Jul 29, 2009

I just installed the Fat Duc O2 manipulator on my 2008 GT1000 last night. It has a Euro ECU and standard exhaust, a stock bike for Singapore. I felt like I was riding a different bike to work today. Here in Singapore stop and go driving is a way of life during the daily commute. I have really been suffering with the chattering and chugging of my GT1000 in low speed manuvering. The transformation brought about by the Fat Duc is truly amazing. Even more amazing when you consider it costs only US$80 and a mechanical idiot like me could install it in about two minutes.

Under 2000 RPM running in 1st, 2nd and 3rd is almost smooth and regular. Also on the freeway I could never cruise in 6th below 4000 RPM(120 km/hr) or below 3500 RPM in 5th (90 km/hr) without feeling like I was chugging the engine to death. Now I actually have a smooth power band from 2800 RPM up in 5th and 3500 RPM up in 6th.

All I did was install the Fat Duc with the default setting between 13.5 and 13.2 air to fuel ratio and I got these results. My question is: can I improve my results by further tuning of the ratio? How will I know if I have made it too rich? I guess if I make it too lean I will go back to the perfomance I had before I installed it. But is there somewhere between the default setting and no enrichemnt that is better? I have seen many threads on the Fat Duc but I have not been able to find one that gives a tuning procedure for mechanically challenged guys like me.

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tsmgguy

· #2 · Jul 29, 2009 (Edited)

I started with the default ratio, as you did. Rode the GT with it that way for well over a year before getting a wild hare to try other settings. The first one I tried was full rich (fully clockwise). I noticed no difference except that the check engine light was on, almost constantly. I backed off (leaned) the setting until the CEL stayed off, and stopped fiddling at that point. I'd say that I'm back to 13.5, or so.

I have the US ECU and stock pipes.

DUCeditor

· #3 · Jul 29, 2009

I find the bike runs best with the Fatduck at the as-delivered setting. Technically I expect it is a little rich - evidenced by the smell of unburned fuel. But for the style of riding I currently prefer it is perfect.

That said I presently have mine set a little leaner, and that to boost the mileage. Without the Fatduck I was averaging about 52 MPG. With the standard, as delivered, setting on the Fatduck it dropped to the mid to high 30s. With my present compromise setting I am seeing mid to high 40s. The price of this is a loss to taht oh so right creamy smoothness at low RPM.

Truth is that mid to high 30s is pretty normal fuel mileage for a 1 liter displacement bike. But with gas stations few and far in between on NH's back roads getting another 8 to 10 MPG is helpful, and the $s saved is a nice added benefit.

As to tuning your own Fatduck, just play around until you get the compromise that works well for you. You won't hurt anything. When the bike feels "right" you've got the best set up and if MPG is important you can simply mark that place on the dial and go leaner when you need the extra mileage per tank.

-odn

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jcasella

· #4 · Jul 29, 2009

DUCeditor said:
I find the bike runs best with the Fatduck at the as-delivered setting. Technically I expect it is a little rich - evidenced by the smell of unburned fuel. But for the style of riding I currently prefer it is perfect.

That said I presently have mine set a little leaner, and that to boost the mileage. Without the Fatduck I was averaging about 52 MPG. With the standard, as delivered, setting on the Fatduck it dropped to the mid to high 30s. With my present compromise setting I am seeing mid to high 40s. The price of this is a loss to taht oh so right creamy smoothness at low RPM.

Truth is that mid to high 30s is pretty normal fuel mileage for a 1 liter displacement bike. But with gas stations few and far in between on NH's back roads getting another 8 to 10 MPG is helpful, and the $s saved is a nice added benefit.

As to tuning your own Fatduck, just play around until you get the compromise that works well for you. You won't hurt anything. When the bike feels "right" you've got the best set up and if MPG is important you can simply mark that place on the dial and go leaner when you need the extra mileage per tank.

-odn

Hey Duceditor, I have pretty much the same setup as you on my SC with your exhaust mod using just 2 holes. The fatduc is amazing for an $80 part, will try slightly leaner after I put a few more miles on.

cDiddy

· #5 · Jul 29, 2009

Any thoughts on whether or not installing the FatDuc would have any impact on the factory warranty? I'm not sure how truthful my dealership is, but they basically told me any mods, other than a dealer installed termi system, could impact/void the factory warranty.

Any basis of truth to that?

Thanks!

tsmgguy

· #6 · Jul 29, 2009

cDiddy said:
Any thoughts on whether or not installing the FatDuc would have any impact on the factory warranty? I'm not sure how truthful my dealership is, but they basically told me any mods, other than a dealer installed termi system, could impact/void the factory warranty.

Any basis of truth to that?

Thanks!

If you are concered about the above, remember that the FatDuc can be removed just as quickly as it was installed. That is, in under five minutes. There would be no evidence that it was ever installed. Hook it back up when you get the bike back from service.

koucki

· #7 · Jul 29, 2009

bmwson: It would be a great idea to play around with the setting, up until you find your favorite. The default setting didn't work for me. I had to change it (can't remember which setting, but I think it's around 3 o'clock), and ride the bike a few miles to notice a big difference.

DUCeditor said:
Without the Fatduck I was averaging about 52 MPG. With the standard, as delivered, setting on the Fatduck it dropped to the mid to high 30s.

Don: I'm riding an '07 SC Biposto, with the FatDuc 02 manipulator and a stock exhaust (no holes). The bike is running better than ever, and the highway consumption is approximately 51mpg (usually running between 4K to 7K RPM).

~k

Biz

· #8 · Jul 30, 2009

I was running 55-57 mpg before installing the FatDuc. After installing it and setting it to about 13.5 (1/8 turn richer than standard), the mileage hasn't dropped much - maybe a couple mpg. If I do a lot of 80+ hiway riding, it will dip into the low 50's. It definitely is working, because the stalling is gone and it runs great at all rpms. The bike runs so good I haven't bothered to richen it up more to see what happens. I need to check the plug color. I can see that the exhaust pipes inside are darker than before so it's richer but I'm surprised the mileage hasn't dropped more. Maybe it was originally so lean that it was less efficient before?

tsmgguy

· #9 · Jul 31, 2009

Biz said:
I was running 55-57 mpg before installing the FatDuc. After installing it and setting it to about 13.5 (1/8 turn richer than standard), the mileage hasn't dropped much - maybe a couple mpg.

I can see that the exhaust pipes inside are darker than before so it's richer but I'm surprised the mileage hasn't dropped more. Maybe it was originally so lean that it was less efficient before?

Same results. MPG is reduced, but it's a good trade off for the bikes suddenly improved manners.

IIRC, it's the low engine RPMs where the problems manifest themselves that originally led to the FatDuc's development, that is, the ultra lean mixture. The FatDuc richens the mixture in this regime. Mixture for RPMs above about 4,000is hardly effected, so the MPG reduction mostly happens in stop and go riding.

Maybe Jason will add to this.

Blacked Out

· #10 · Aug 1, 2009

What grade fuel are you guys using?

jcasella

· #11 · Aug 1, 2009

I agree, your highway mileage should stay about the same..

bmwson

Discussion Starter · #12 · Aug 2, 2009

First Fat Duc Adjustment

After a week of riding I went to another 1/8 of a turn clockwise (richer). Low RPM throttle control even more smooth than with the default setting. I will start to take more careful measurements of fuel consumption.

quidpro

· #13 · Aug 4, 2009

This is a timely thread for me as I was about to declare the my FatDuc wasn't working any more...I had lost the "smoothness" at lower speeds/rpm and was getting the "bucking" again that had disappeared when I put it in. I'll tinker around with it..perhaps it needs "tinkering." Not sure why it is misbehaving

bmwson

Discussion Starter · #14 · Aug 11, 2009

Fuel consumption

After two tanks of fuel at my current Fat Duc setting (1/8 turn richer than default) I am getting 18.7 km/litre or about 43.9 mpg with 50/50 mix of highway and city riding. I use Shell V-Power fuel and I have Bridgestone BT-021 tires.

JT992

· #15 · Aug 12, 2009

I can tell you guys this

Last saturday during dyno days we had a 08 hyper all stock running above 18 A/F ratio tell 5500 rpm then it would start to drop down to 13 A/F by about 6300 rpm. The next day I put my 08 multi all stock on my buddys dyno just to see and it did the exact same thing. I ordered a 02 manipulator this morning. When it gets here I am going to tune it on the dyno. Hope it will pull down to 13 A/F way before 5500 rpm. According to ducati there head and valve angle now lets them burn lean and not hurt anything must be true.............Cause 18 A/F is not ideal

johnnydanger

· #16 · Aug 17, 2009

My experience: I'm running Staintune and have a drilled airbox with the standard (lean) ECU. I installed the FatDuc to richen up the low rpm to smooth out performance around town, and also to get rid of the damn popping on/off throttle while in closed loop. It did both things excellently but required some tweaking over time.

I'm quite a ways past the stock setting now -- turned clockwise to straight left/right. I realized early on the once a new setting was chosen I needed to leave it alone for a couple days before it all settled into the new settings and the ECU rethought out it's fuel map. Basically I kept turning it up until the popping and lean running conditions went away. Now it's awesome. Runs great.

One note of caution: I originally installed it and left the FatDuc in the center area under the seat over the ... rectifier? The hot finned thing. At one point during a longer ride, the yellow check engine light came on and the popping had come back. Weird. I thought I'd set something wrong, but I quickly realized that the intense heat coming off the finned box was cooking the FatDuc and making it go wonky. I realigned the FatDuc with the wires on the right side of the underseat and immediately all was good again. No more check engine light, no more popping. Ahhh, nirvana.

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ShuSiFu

· #17 · Jul 27, 2015

Bringing this one back.

I jut got the Fat Duc and installed it on my 2007 GT1000 as per image below.

But, there are two pieces it can connect to. I put it in the red one. Anyone know if that's wrong and it should go in the blue one?

Advice appreciated.

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bill1960

· #18 · Jul 27, 2015

ShuSiFu said:
Bringing this one back.

I jut got the Fat Duc and installed it on my 2007 GT1000 as per image below.

But, there are two pieces it can connect to. I put it in the red one. Anyone know if that's wrong and it should go in the blue one?

Advice appreciated.

One is the fuel pump wiring harness. Its easy to trace since its just a short cable going to the fuel pump mounted in the bottom of the tank.

The other harness goes to the O2 sensor mounted on the exhaust header pipe. Connect it inline with that one.

This may help

jlduck

· #19 · Jul 27, 2015

What Bill 1960 said. Find the 02 wiring coming out of the exhaust and trace it back. Didn't your FatDuc come with instructions?

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