Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > General Motorcycles only > S4r fuelling

[rockhopper]

Termis are really no different to the cans you have got (with the baffles out) so therefore why would you get a new ECU with the termis if you didn't need it? The map in the stock ecu will be for the stock bike with standard cans, filter, etc. If you change any of those things then the ECU cannot magically change its map to allow for that. You need a new ECU or a PC3. On the older bikes like mine you just slip in a £30 JHP chip.

What is your actual MPG? Can you smell petrol in the exhaust? Does it start from cold and hot easily, with or without the fast idle?

[Lee1980]

Yeah i guess the can is the same apart from theres only one instead of 2 cans, i got can just before 600 miles service so they could tweak it after i put it on. Maybe the stock ecu just can cope. I dont want more power and dont want to spend any more, just want half decent mpg

I did the chip on my 748s from jhp so much eaiser why the hell did they change the way it works beats me, now need to spend more to get it to run better lol

not sure of actual mpg, but tank hold 15 litres and last 2 fill up have got about 60 miles till light comes on then got in nearly 11 litres so this means the light is working ok assuming reserve is around the 3.5/4 litre mark

Not sniffed will tommorow lol, doesnt start as well as 748 used to and cuts out till its low temp dissapears on guage.
It wont start with out the choke (its proper choke not like fast idle button on 748) and keep running till warm, where as the 748 never need the fast idle unless real cold.

[rockhopper]

Its not a choke although it has a lever in the same way a choke has, its still just a fast idle control.

Okay, well it shouldn't cut out like its doing, it should just run normally like you wouldn't know it was cold. Like your 748 used to i guess so there is certainly something wrong somewhere.

Rushjob has some kind of magic electric box thingy plugged into his ST4S (same motor as your bike) which does a similar job to a PC3 but is a bit cheaper i think.

I suspect something like that is the only way your bike is going to run correctly.

Might be worth letting the dealer have another crack at it though.

Of course i could be talking rubbish, hopefully someone more knowlegable than me will be along soon!

[Lee1980]

Yeah i see what u mean its not a choke but can put gradually (little bit or a lot) unlike the button the 748s.

It only cuts out when cold before it reach 40 degrees c never once warm, I dont want to buy anything really for it never thought it would be this bad

He says its to do with back pressure removing cans takes some away so it got to be richened, i think the new cans are a lot more restrictive that 748 cans. If I take of cat be even more richer 50 miles a tank anyone??

[rockhopper]

The new cans should be less restrictive than the old ones which tends to make the bike run lean. The ECU cannot richen the mixture up becasue it hasnt got the lambda sensor in the exhaust to measure what is going out of the engine, all it knows about is air temp, air pressure, throttle position etc and it matches that information to the fuel map in its memory whcih then adjusts the mixture and ignition timing to give the desired end result. If you change things then the map in the ecu needs changing to compensate. I think there is a trimmer pot which allows you to adjust the idle CO but this won't always be enough.

I would try putting the stock cans back on and see what happens.

[Lee1980]

I see Paul might just ask them to put mine back to stock settings if they will, then they might not cause of running lean

[rockhopper]

Running lean can be bad becasue the petrol actually cools the engine so if there isnt enough petrol then the engine can run very hot and eat itself in short order. It has to be excessivly lean for that to happen though.

[Lee1980]

Think i might ask them to go back to standard settings tommorow if they can fit me in

[Lee1980]

Well i'll bo foooked got 50 miles till the light came on today

Its getting worse! its booked on next Sat to have it put back to standard settings, cant come soon enough may as well pour half down the drain when filling up

As I still have the cat on there, im sure i read somewhere that to much fuel can damage the cat in some way? any one know?

[Paul996]

Lee
Fitted a full sparks system to mine with no other adjustments and still get in the 90's with fuel consumption.
Don't ride it like a pansy either