S4r fuelling
 

I have an S4r with an akrapovic slip on with baffles removed, and have had fi tweaked by dealer to suite first time round it ran real bad lots of flat spots. The mixture was then richened runs much better but im getting the fuel light come on at 60miles and getting in about 11 litres which mean the fuel light is working ok to.

Is this cause they can only adjust it so far? or are they just not good at it? i was planning on replacing the udder for spareshack pipes but he said this will make it even richer

He said it was something to do with there not being enough back pressure? when they are straight through cans etc?

Think you'll get the best results with a PC3 fitted and set up on a roling road if you fit cat bypass, thats what I intend to do when I can afford it ;)

Darren

Don't you need to change the whole ECU on those bikes if you change the cans? Might be wrong though.

The Ecu would be changed if i had termis with the ecu, im sure u can buy just the termi slip ons and not the ecu though:puzzled:

I never thought a slip on would make so much diffrence:o:o

There should be enough tolerance in the stock ecu.You only need to go the PC3 route is if you are playing around with the intake with different filters etc.
I'm runng a full Arrow system and it is perfect,with no other mods.Baffes in
though,its toooooooooo loud with them out!

I would suggest that the different exhaust will have more effect than changing the air filter etc mainly becasue the FI system doesnt have a lambda sensor. As daz rightly says, a PC3 is a subsitute for the DP ECU.

Logyk got really good results from a PC on his S4R. Open pipes, no cat. DynoJet used his bike for there downloadable map.
Very smooth with good hp and torque.

Thanks for replies guys:D:D

Im sure a Pc3 would give good results but im not prepared to spend that amount yet ( any one got one cheap lol) maybe later if i take off the cat.

Mine goes well enough just a bit dissapointed with fuel consumption/tank range:o:o

Will making it richer mean it doesnt make so much power? As i find it hard to power wheelie when i thought it would easily come up on the power, i can rev to 8k in first and it still dont come up:o

Who did the work?

Only main dealer in Bristol (those that dont know Riders of Bristol) oooops

Maybe its the stock ecu not being good enough etc or because i haven't got termis:o:o

[Edited on 6-10-2005 by Lee1980]

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?

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:D

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.

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!

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 :lol::lol:

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 :lol: 50 miles a tank anyone??

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.

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:sniff:

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.

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

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

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:lol::lol:

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?

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:sing::)

You know, my bike never ran all that well until I took it to a specialist. Neil at sigma performance set all that ecu, chip, cans, idle, trim, level, flux capacitor stuff out and it was sweet after that. If it's not under warranty then take it to your nearest specialist (Nelly, Sigma, ProTwins, TecMoto etc etc). Well worth it in the end.

Hehe I don't ride lika pansy either :lol::lol: its lots of stop starting commuting u know gassing it from the lights so prob get around 80 till light comes on but 50 is so low:o:o

If my dealer wasn't going to put it back to standard i was going go to luigimoto and as its still under warranty best stick with main dealer for now:D:D:D

Yay been put back to near standard as possible with 4% co2 i think feels alot better like its burning fuel cleanly sounds good on the overun to, pop, pop pop pop :D

Not sure how much power not opened it up yet due to crappy weather :mad:

Think a 14t will be needed next :D

Glad its sorted i think, was starting to get fed up with it :eek: